Understanding Addiction: From Linguistic Roots to Contemporary Perspectives

Addicere, the Latin word from which addiction derives has the original meaning of being “bound to” or “enslaved by” something (Maddux & Desmond, 2000), not specifically a substance or behaviour. However, in today’s society, this term is most strongly associated with drugs, alcohol and certain behaviours. The current definition from The American Society of Addictive Medicine classifies addiction as a continuing disease wherein dysfunctions in brain-rewards, memory, motivation and related circuitry lead to alterations in an individuals’ psychology, biology, spirituality and social status (“ASAM Definitions of Addiction”, 2018). The primary and current definitions are collaborated by Love, Laier, Brand, Hatch and Hajela (2015), to define addiction as the pursuit of a neurochemical reward which is uncontrollable and preventative of activity disengagement, similarly Alavi et al., (2012) suggests that an individual has developed an addiction when their habit becomes an obligatory act, they are fundamentally consumed or enslaved by it. Most voluntary human behaviours provide us with stimulation and gratification, for example; food, sex, love, shopping or gambling, and the need for this reward can result in the development of a compulsion and addictive tendencies (Widyanto & Griffiths, 2006). The same neuropathways are activated during the development of alcohol or drug addiction, where clinical diagnosis primarily focuses. For those exploring the psychological aspects of addiction in their research, seeking psychology dissertation help can provide valuable insights and guidance.

Over recent years, the drug crisis in the United Kingdom has become more prominent, with a 10% increase in the number of drug misuse connected deaths from 2014-2015, followed by a 6% increase in hospital admissions associated with poisoning of illicit drugs and drug-related mental health and behavioural disorders between 2015-2016 (NHS Digital, 2017). On a global scale, substance use disorder resulted in the deaths of 307,400 individuals in 2015, with opioid use disorder and alcohol use disorder instigating the largest number of fatalities (Wang et al., 2016). The data shown both nationally and worldwide suggests an increase in the number of substance use disorder diagnosis, a condition associated with a multitude comorbidities, including both behavioural and psychological disorders (NIDA, 2018), therefore advocating further research into these comorbidities in order to advance early intervention and therapeutic treatments beyond pharmaceuticals such as methadone or buprenorphine.

When identifying addiction, the key diagnostic tools used are the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5; APA, 2013) and the International Classification of Disease 10th Revision (ICD-10; World Health Organisation; WHO, 1992) although the ICD-11 (WHO, 2018) will be published in 2018, it’s draft copy shows developments in this diagnostic criteria which will be adopted in this discussion. The DSM-5 titles addiction as “Substance-related and Addictive Disorders”, listing ten categories of addictive substances, these include: alcohol; cannabis; inhalants; opioids; sedatives, hypnotics or anxiolytics; nicotine; caffeine; stimulants (including; amphetamines, cocaine and other stimulants); hallucinogens (including phencyclidine, arylcyclohexylamines, and other hallucinogens, such as LSD); and other unknown substances. Each category consist of the same diagnostic criteria (Hasin et al., 2013), formed of eleven pathological behaviours, divided into four categories: 1) impaired control; the increasing of substance dosage more frequently than intended; 2) social impairment; the prioritisation of substance, resulting in the neglect of important social and occupational occasions due to the substance; 3) risky use; involves the continuing use of the substance, regardless of the legal or physical dangers one might me experiencing; 4) pharmacological indicates; the experiencing of cravings when absent from the substance (Hartney, 2016).

The ICD-11 has substance dependence as the central diagnosis of addiction, defining it as a clinical disease composed of behavioural, cognitive and physiological qualities manifesting an internal driving force to use a substance (Saunders, 2017), categorising addictive substances in a more specific way than the DSM-5. The categories include: alcohol; cannabis; synthetic cannabinoids; volatile inhalants; opioid; sedatives, hypnotics or anxiolytics; nicotine; caffeine; stimulants (including amphetamines, methamphetamine or methcathinone); synthetic cathinones; cocaine; dissociative drugs (including ketamine and phencyclidine); hallucinogens; MDMA (and related drugs including MDA); other specific psychoactive substances; and unknown or unspecified psychoactive substances.

With the use of the DSM and ICD to provide a clinical diagnosis of substance use disorder in a categorical way, alternative measurement tools are used by researchers and medical professionals to determine whether an individuals is suffering of an addiction to a substance and the severity of this problem, using an alternative paradigm approach. With the development in research and knowledge surrounding drug and alcohol misuse, a variety of measuring tools have come into production, measuring either alcohol, drug, or combined abuse of these substances. The Externalising Spectrum Inventory (ESI; Krueger, Markon, Patrick, Benning, & Kramer, 2007) and ESI-brief from (ESI-bf) was created by Patrick, Kramer, Krueger and Markon (2013) to measure a variety of problematic behaviours relating to diminished impulse control, including: alcohol use and problems; drug use and problems, and general substance abuse. Though this tool has been found useful in much research of impulse control, this measure is not solely related to drug and alcohol problems, and therefore does not measure the magnitude of substance misuse in a dimensional way, but scores for a range of risky outcome behaviours. Aa alternative measure used for both alcohol and drug use is The Clinician Rating Scales for Alcohol and Drug Use (CRS–Alcohol and CRS–Drug; Drake, Osher, & Wallach, 1989), wherein statements were responded to using a 5-point Likert scale, reflecting levels of alcohol or drug use over a timeframe of the previous 6 months, these responses revealed a problem level ranging from none to problems of extreme severity. Within the populations used, this tool produced high levels of reliability and validity (Carey, Cocco & Simmons, 1996; Drake & Wallach, 1989).

However, one of the simplest measures for substance misuse is the Drug Abuse Screening Test-28 (DAST-28; Skinner, 1982a). Though an old measure, this simple 28-item self-report measure, which can also be administered by a clinician, has frequently been used in research, measuring substance use over a 12-month period. Since its creations, the DAST-28 has been adapted to create the shorter DAST-20 (Skinner, 1982b), DAST-10 (Bohn, Babor, & Kranzler, 1991) and DAST-Adolescence (DAST-A; Martino, Grilo & Fehon, 2000). Each alteration of these tools has maintained statistical reliability and validity, making it a useful and trustworthy gage of addiction within research.

Addiction often goes hand-in-hand with other psychological disorders, for example, Gudonis, Derefino and Giancola (2009) argue a high level of comorbidity between psychopathy and substance use disorder, with this dual-diagnosis showing an increase in incarcerated individuals (Hopley & Brunelle, 2012). Research by the National Institute of Drug Abuse (NIDA, 2008) determining that individuals which classify as having substance use or dependence disorder, as diagnosed by the DSM-5, in comparison to a control group, are two times more likely to have a personality disorder, such as psychopathy. Similarly, Neumann and Hare (2008) uncovered an increased level of alcohol use in individuals displaying psychopathic traits, with a prevalence increase for alcohol abuse 1-2% in individuals scoring highly for psychopathy using the Psychopathy Checklist-Revised (PCL-R; Hare, 1996). However, the direction of this relationship is often questioned, some psychologists argue that psychopathy may lead to substance se disorder aa a coping mechanism, whereas other researchers have put forward the idea that drugs and alcohol reduce inhibition, thus preventing the individual from controlling and burying their antisocial behaviours associated with this diagnosis.

Psychopathy is a personality disorder which manifests itself through emotional deficits (e.g. lack of remorse or empathy, shallow affect or callousness) and behavioural characteristics (e.g. manipulativeness and grandiosity), in addition to increased disinhibition which can lead to reckless behaviour (Hare, 2003). Although clinically classified as a personality disorder, with central focus on inadequacies in emotionality, rather than behavioural factors (Buzina, 2012; Hare, Neumann, & Widiger, 2012), Cornell et al., (1996) argued a combined approach to psychopathy, defining the disorder as one which produces both behavioural and social problems. Cornell et al., (1996) also suggested that individuals with mental health disorders were poorly diagnosed with this disorder (Anderson, Sestoft, Lillebaek, Mortensen & Kramp, 1999; Hare, 2003).

With an estimated prevalence of psychopathy in >1% of the general population, (Coid, Yang, Ullrich, Roberts, & Hare, 2009), however the frequency of this personality disorder rises significantly within prison populations (Coid et al., 2009; Kiehl & Hoffman, 2011). Due to the increasing portrayal of film and television dramas depicting the stereotypical “psychopath” committing unforgiveable crimes, this concept has become highly colloquialised in society today’s, consequentially resulting in a loss of meaning and disillusioned definition. Individuals diagnosed with this personality disorder often display symptoms such as; superficial charm, impulsivity, the ability to manipulate others, along with inadequacies in levels of nervousness, remorse, shame, mendacity and empathy (however they are able to exploit the empathy of others; Buzina, 2012; Hare, Neumann, & Widiger, 2012; Kiehl & Hoffman, 2011; "The Worlds Most Experienced Hypnotist", 2017; Ullrich, Farrington, & Coid, 2008).

Originally defined as “mania without delusions” (“mania sans délire”), Phillipe Pinel first devised the term psychopathy, suggesting it be an accumulation of three characteristics: impulsive sanity with moral idiocy, hypomania and melancholic activity (Millon, Simonsen, & Birket-Smith, 1998). Conversely, a more current explanation of psychopathy is provided by Cleckley (as cited in Buzina, 2012), who presented sixteen defining criteria of the psychopathic personality, depicting diagnosed individuals as having: lack of remorse or shame and mendacity, absence of nervousness, superficial charm and qualities useful for white collar businessmen (Ullrich, Farrington, & Coid, 2008). Cleckley’s theory is still used in research today and has been used in the development of the Psychopathy Checklist Revised (PCL-R; Hare, 1991), an adult tool which measures traits of psychopathic traits using a 20-item questionnaire. This diagnostic measure took a dimensional approach to the personality disorder, denoting that an individual may present one facet of psychopathy, whilst being absent or exhibit low levels of another, presenting them along a spectrum, rather than a categorical diagnosis. The categorical diagnosis method adopts a medical perspective, wherein individuals are labelled as having psychopathy or being non-psychopathic (Edens, Marcus, Lilienfeld, & Poythress, 2006; Guay, Ruscio, Knight, & Hare, 2007). This approach is used by the American Psychological Association (APA) who produce the Diagnostic and Statistical Manual for Mental Disorders (DSM), meaning a specific number of certain characteristics must be presented for a diagnosis to be given. With deception playing a role in the difficulty of determining the degree to which these traits must be displayed, consequentially, psychopathy was removed from the DSM-5 (APA, 2010; APA, 2013). Now containing the category “Antisocial Personality Disorder” (ASPD), the DSM-5 enlists psychopathy as a smaller and less prevalent disorder, suggesting only 1 in 5 of those diagnosed as having ASPD display traits of psychopathy (Kiehl & Buckholtz, 2010).

Despite the clinical reliance of the DSM for diagnosis of many psychological disorder, the dimensional approach is still favoured by many researchers and found to be most effective for diagnosis (Skodol et al., 2005). A dimensional approach to this phenomenon allows the divergence and expansive nature of psychopathic traits to be placed along a spectrum between adaptive and maladaptive characteristics, permitting the degree and severity to be determined, along with the monitoring of diagnosis over time (Tyrer, 2004). This approach coincides with other theories of personality, including the Five Factor Model of Personality (FFM; McCrae & Costa, 1996), which provided five characteristic domains (Neuroticism, Openness, Agreeableness, Conscientiousness and Extraversion), which have been shown to mirror within psychopathy (Derefinko & Lynam, 2013). This research found that individuals diagnosed with psychopathy displayed show low levels of agreeableness, conscientiousness, self-consciousness (within neuroticism), positive and warm emotions (under extraversion), in conjunction with high levels of hostility, impulsivity (part of neuroticism) and excitement seeking (within extraversion). The fundamentals of the FFM have been embraced into the development of other measures of psychopathy, including Hare’s Self-Report Psychopathy Scale (SRP; Hare, Harpur, & Hemphill, 1989), the Psychopathic Inventory (PPI; Lilienfeld & Andrews, 1996); Hare’s Psychopathy Checklist- Revised (PCL-R; Hare, 2003) and the Elemental Psychopathy Assessment (EPA; Lynam et al., 2011). These tools measure the maladaptive trait variants across the construct of psychopathy, without sacrificing the association to broader-scale personality traits.

Regardless of its removal from the DSM as a singular diagnosis, this disorder has become of focus by researchers (Buzina, 2012), Neumann (2015) uncovered a 143.9% increase in published research papers on PubMed between 1990-2010, regarding psychopathy and their association with an assortment of outcome behaviours, including substance misuse and criminality (Hemphill, Hart & Hare, 1994; Konicar et al., 2015; Smith & Newman, 1990). Included in this research is the development of the most recent approach to psychopathy, Triarchic model of psychopathy (Patrick, Fowles, & Krueger, 2009), wherein the construct of psychopathy has been divided into three distinct constructs: Boldness, Meanness and Disinhibition which can be reflected from the work of the FFM. Upon the development of this novel approach to psychopathy, The Triarchic Psychopathy Measure (Tri-PM; Patrick, 2010) was developed using the work of previous measures and the theory in hand, this tool produces an overall score for psychopathic traits, in addition to scores for its three constructs. Poy, Segarra, Esteller, López and Moltó (2014) conveyed that, in regards to the FFM, boldness correlated with high levels of openness and extraversion, but low levels of neuroticism, consistent with previous theories of social potency, fearlessness, narcissism and aggressive pathology. In relation to previous measuring tools, the boldness facet mirrors fearless dominance of the PPI-R (Drislane, Patrick, & Arsal, 2016; Esteller, Poy, & Moltó, 2016) showing prominence to the positive-adjustment mechanisms within psychopathy which both theories behind these measures display. Similarly the PCL-R (Hare, 2003) also shows to support for the boldness facet by encompassing similar traits within Facet 1 (interpersonal) (Patrick, 2010; Venables et al., 2014).

Like Boldness, Meanness is related to external personality traits, intersecting with the lack of empathy and fearlessness traits of boldness, meanness also encompasses FFM traits of low conscientiousness and agreeableness (Sellbom & Phillips, 2013; Stanley, Wygant, & Sellbom, 2013). Utilising both interpersonal-affective and behavioural traits of psychopathy, meanness correlates positively to both Factors of the PCL-R (Factor 1: selfish, callous and use others without guilt or remorse; Factor 2: antisocial, chronic instability and socially deviant) (Venables et al., 2014). Also relating to Impulsive Antisociality and Fearless Dominance aspects of the PPI-R (Esteller et al., 2016).

The third component of the Triarchic Model of Psychopathy is Disinhibition, argued to be unequal to psychopathy on its own (Partrick et al., 2009), disinhibition is reflected within psychopathy in combination with dispositional Boldness and Meanness. This component has been comprehensively portrayed by Facet 3 (Lifestyle) of the PCL-R (Hall et al., 2014; Venables et al., 2014), including characteristics such as recklessness, impulsivity, irresponsibility and self-indulgence. This trait is associated with increased levels of neuroticism, anxiety, sensation-seeking and reward sensitivity (Poy et al., 2014), depicting the Impulsive Antisociality dimension of the PPI-R (Esteller et al., 2014; Hall et al., 2014; Sellbom &Phillips, 2013).

There are various neurological differences in those with psychopathy in comparison to controlled populations, with psychopaths displaying a hypersensitivity towards rewards, resulting in a pathological drive for anything which gives reward or pleasure, regardless of the consequences (Buckholtz et al., 2010). Including a desire towards sex, money, egocentric status and drugs (Buckholtz et al., 2010). For individuals with psychopathy, this increasing of activation in the dopamine circuits occurs when anticipating a reward, creating a more impulsive personality. Seara-Cardoso, Sebastian, Viding and Roiser (2016) found that in this populations, the amygdala and anteria insula, areas involved in emotion and empathy, showed reduced levels of activation when triggered. Similarly, Blaire (2008) found below normal functioning in the amygdala and ventromedial prefrontal cortex (vmPFC) in psychopathic participants, areas of which are highly interconnected (Price, 2006), explaining the decreased levels of fear processing and thus risky or dangerous behaviour performed by those with psychopathy. Buckholtz et al (2010) used Positron Emission Tomography (PET) scans and Functional Magnetic Resonance Imaging (fMRI) to measure activity levels in the brain, and map these areas in response to reinforcers. Their research supported previous findings, showing how dopamine release from the nucleus accumbens (NAcc) along with reward anticipation can be predicted by impulsive-antisocial psychopathic traits, preventing normal self-regulation, displaying how the increase in dopamine levels in psychopathic individuals increased the risk in the development of substance misuse problems (Smith & Newman, 1990).

With psychopathy’s classification as a personality disorder, the two main brain deficits are in the amygdala and vmPFC (Blaire, 2008), these areas are key in learning the differences of right and wrong through socialisation (Wootton, Frick, Shelton & Silverthorn, 1997), and as individuals exhibiting psychopathic traits have deficits in these areas, they are ignorant to these morals, unable to learn through social interaction, they can become more antisocial to achieve their goals. The amygdala plays a fundamental role in stimulus-reinforcement learning, allowing neurotransmission of information regarding stimulus-reinforcement expectancies to the vmPFC, for decision making to take place (Schoenbaum & Roesch, 2005). Research of individuals displaying traits of psychopathy has revealed reduced amygdala activity during aversive tasks, involving punishing or unpleasant stimuli (Birbaumer et al., 2005), in addition to a reduced response to fear cues and emotion (Hare, Frazelle & Cox et al., 1978) and emotional distractors (Christianson et al., 1996; Mitchell, Richell, Leonard & Blair, 2006). Similarly, as activity of the vmPFC is triggered by the amygdala, debilitated activity subsequently occurs here also. This impaired connectivity has shown to display a lessening in the differentiation in these two area during the completion of tasks involving loyalty or allegiance (Rilling et al., 2007). This evidence supports the outcome behaviours of those with traits of psychopathy, including; poor moral decision making, rebellion, superficial charm and disregard of others emotions.

With its main identifier centring on diminished emotional affect, and reduced ability to understand the emotions of others, psychopathy can be mirrored against Autism Spectrum Disorder (ASD). The paralleling traits in these two disorders can be explained by the similarities in neurobiological differences to the neuro-typical brain, with both disorders exhibiting atypical amygdala dimensions and functioning (Blaire, 2008; Jones, Happé, Gilbert, Burnett & Viding, 2010). Likewise in psychopathy, a diminishment of amygdala activation occurred during social tasks involving emotional decision making in individuals with ASD (Hennessey, Andari & Rainnie, 2018). In addition, neuroimaging studies showed a reduced number of neurons in adults with ASD, averaging a 17% reduction in comparison to neuro-typical controls (Auino et al., 2018).

This evidence supports that Psychopathy and ASD are connected by distinct neurocognitive foundations (Blair, 2008; Gillespie, McCleery & Oberman, 2014), imitating in their reduced ability for normalised human social interaction. This is exemplified through research on psychopathy and ASD and their relationship with the Theory of Mind (ToM; Gillespie, Mitchell & Abu-Akel, 2017). Defined as the capability to understand the mental states of others, ToM comes in two forms: cognitive ToM, allows one infer the beliefs, intentions and thoughts of another individual, whilst affective ToM consists of the ability to recognise the emotions and feelings of others, unlike empathy, ToM signifies the skill of understanding the emotional mental states of others, rather than adopting their affect and what they feel (Preckel, Kanske & Singer, 2018; Shamay-Tsoory, 2010). Research has shown that both psychopathy and autism are both associated with problems in affective ToM functioning (Baron-Cohen, Wheelwright, Hill, Raste & Plumb, 2001; Gillespie, Mitchell & Abu-Akel, 2017), with errors of affective ToM correlating positively, and in a unique manner to psychopathic tendencies (Gillespie, Mitchell & Abu-Akel, 2017). This evidence is supportive of existing diagnostic characteristics of psychopathy and ASD wherein impaired emotionality and ability to understand the emotions of others has a subsequent impairment on social interaction (APA, 2013; Hare, 2003).

As with psychopathy, the neurological basis of addiction has been associated with the amygdala in addition to the Ventral Tegmental Area (VTA) and Nucleus Accumbens (NAc). The most prominent neuro-circuitry system involved in addiction is the Mesolimbic Dopamine Reward Pathway, when engaging in rewarding behaviour, this area is activated and instructs the brain to repeat the occurring behaviour in order to receive the same reward again. Addiction is vastly connected with the flooding of dopamine into the reward pathway (mesolimbic pathway) in this brain. This dopaminergic pathway is combined of the ventral tegmental area (VTA) within the midbrain, which connects to the nucleus accumbens (NAc) in the ventral striatum (Dryer, 2010). The dopaminergic neurons are located within the VTA, this area responds to external stimuli and informs the organism as to whether it is aversive or rewarding. The neurons then target the NAc, wherein the rewarding effects of the stimuli are mediated. Dopamine in this system plays a regulatory role for movement, desire, emotional regulation, and motivation for rewarding stimuli, reinforcing behaviours which give pleasure (Berridge & Kringelbach, 2015).

Although not the primary brain area associated with addiction, recent research by Warlow, Robinson and Berridge (2017) had found that the amygdala also plays a key role due to its role of forming emotional memories bases on learning through reward and punishment, forming a motivational connotation to a particular stimuli (Warlow, Robinson & Berridge, 2017; Yasoshima, 2015), in this research the stimuli was cocaine. The amygdala, though not directly involved in the reward pathway, regulates the mesolimbic dopamine system, including the activity of the nucleus accumbens (Ahn and Phillips, 2002; Janak and Tye, 2015; Reppucci and Petrovich, 2016), in addition to converting a preference into a compulsion by biasing choice (Tom, Ahuja, Maniates, Freeland & Robinson 2018). Result of this study concluded that activation of the amygdala in rats, when administered liquid cocaine, intensified the motivation to receive the drug again. This motivation was three times higher than the normal levels of motivation in drug users, consequentially trembling their measure of hard work.

Similarly Wassum and Izquierdo (2015) uncovered that long term drug use caused damage to the amygdala, this subsequently implicates the functioning of this brain area, diminishing signalling from the amygdala and therefore devaluing reward from the drug. The devaluation of this drug plays a role in the development of addiction, wherein the individual increases their dose or frequency of substance consumption to achieve the same outcome as their first usage.

Structural differences in specific regions of the brain has shown to predispose individuals towards substance abuse (Joseph, Jiang, Lynam & Kelly, 2009; Society for Neuroscience, 2016). Specifically research has found that individuals susceptible to seeking stimulation and impulsive behaviour have these neurological variants (Zuckerman, 2008), suggesting a relationship between the two behaviours. Sensation seeking is defined by Zuckerman (1994) as a personality trait wherein a person pursues a variety of novel, complex and intense experiences and sensations, in addition to willingly partaking in financial, legal, physical and social risks to achieve the stimulation which they seek. Individuals who produce high sensation seeking scores generate a stronger skin conductance response to sexually explicit and violent stimuli (Smith, Davidson, Perlistein, & Gonzalez, 1990), meaning a theoretical link can be made between this personality trait and those of psychopathy, wherein violence is highly correlated. Studies have suggested that personality traits of impulsivity, including sensation-seeking enhanced an individual’s susceptibility towards drug-seeking behaviour and relapse (Ersche, Turton, Pradhan, Bullmore & Robbins, 2010; Everitt et al., 2008), with supporting research from de Castro, Fong, Rosenthal and Tavares (2007) and el-Guebaly et al (2006) who found that in 63% of individuals seeking treatment for Gambling Disorder, also produced a positive screening of Substance Use Disorder at some point in their life (Grant & Chamberlain, 2010). Similarly, a study by Grant, Potenza, Weinstein & Gorelick (2010) in a clinical sample, established a 50% comorbidity of substance abuse in participants with Gabling Disorder. Stimulant dependent persons, when compared to controls have reported significantly higher levels of impulsivity, with particular focus on sensation-seeking (Ersche, Turton, Pradhan, Bullmore & Robbins, 2010), however, it can be questioned whether this heightened level of sensation-seeking is an outcome of stimulant drug use, or whether stimulants are used due to the individual seeking a novel and exciting experience.

Research giving evidence for the comorbidity of addiction and sensation-seeking can also be supported by looking at the neurological underpinnings of the traits of sensation-seeking in abusers of heroin by Cheng et al (2015). This study found a differing in cognitive control and reward processing between heroin abusers and non-abusers, in which the midbrain, an area critically involved in the movement of head and eye gaze (Mihailoff, Haines & May, 2018), of heroin users showed decreased volume, with increased traits of sensation seeking. These findings indicate a potential association between the brains neural reward system and the excessive compulsion to seek sensations. Further neurological variances have been uncovered in individuals displaying increased levels of sensation seeking. Holmes, Hollinshead, Roffman, Smoller & Buckner (2016) revealed areas of cognitive control, which play a role in the desire to seek sensory experiences (Cheng et al., 2015; Mihailoff, Haines & May, 2018) where covered by a cerebral cortex of reduced thickness. These areas where therefore limited in their function, subsequently leading to atypical performance and decrease in self-regulation towards thriving for increased sensations, putting the individual at an increased risk of turning to substance abuse and other risky behaviours.

Since the proposal of the sensation-seeking personality traits, by Zuckerman in the 1960s (Zuckerman & Aluja, 2015), several psychometric measures have been developed to conceptualise this characteristic. Zuckerman developed several forms of the Sensation Seeking Scale (SSS) with the most recent being Form V (Zuckerman, 1996). This tool was developed from the psycho-biological model, along with the idea that sensation-seeking does not always involve risks such as substance abuse. This 40-item measure places emphases on four facets of sensation-seeking: Thrill and Adventure Seeking, Experience Seeking, Disinhibition and Boredom Susceptibility. The Brief-form of the Sensation Seeking Scale (BSSS; Hoyle, Stephenson, Palmgreen, Lorch & Donohew, 2002), maintains focus on the four facets of sensation-seeking tendencies, whilst avoiding acts like drug and alcohol misuse. Contracted into a simple 8-item tool, Chronbach’s alpha scores varying from 0.74-0.79 suggest this measure is reliable and still appropriate irrespective of its minimal behavioural coverage.

In continuation from the biological approach to personality which the SSS was developed on, the Novelty Seeking Scale (NSS; Cloninger, Svrakic, Bayon, & Pryzbek, 1999), a part of the Temperament and Character Inventory Revised (TCI-R) again puts focus on: Exploratory Excitability, Impulsivity, Extravagance and Disorderliness, measuring these aspects across 60-items. However, unlike the SSS, this measure has showed to behold problems with psychometric factor validity, regardless of this, the NSS has been used commonly within research (Zuckerman & Aluja, 2015).

All measures and approaches to sensation seeking consider centrality of perusing novel experiences to achieve new feeling, this factor corresponds with one of the five factors of Hare and Neumann’s (2008) theory of psychopathy. With research suggesting sensation seeking is related to traits of a psychopathic personality (Blackburn, 1969), support is found within the Tri-PM, wherein disinhibition stands as one of the three facets of psychopathy. Disinhibition coincides with the idea of sensation seeking as both can involve the disregard for consequences of the actions, in addition to a need for immediate gratification (Dickey, 2014). Hopley and Brunelle (2012) found that high impulsivity, related to sensation seeking, acted as an indirect facilitator in the development of stimulant dependence in individuals displaying traits of psychopathy.

Although existing research between psychopathy and addiction is limited (Werner, Few & Bucholz, 2015), and even more so with the addition of sensation-seeking, the correlation which have been observed open the door for further investigation. With individuals with psychopathic traits displaying an increased risk of misusing certain drugs due to underlying personality-based differences, including increased sensation seeking (Hopley & Brunelle, 2012), this is suggestive of a potential three-way relationship. Consequently, in consideration of the literature reviewed and the developments of theories and knowledge in the field, the objective of this exploratory research is to build upon this area, investigating the correlations between psychopathy and substance addiction, examining whether specific traits of psychopathy correlate more highly with specific drug types, create an advancement in knowledge around addiction and its correlational traits with psychopathy and sensation-seeking and to observe if the three facets of Psychopathy, based upon the Triarchic Psychopathy Measure, correlate with the three constructs of Sensation-Seeking proposed by the UPPS-P. This research has the potential to develop the awareness around individuals scoring highly for psychopathy and how to best encourage and treat their substance misuse problems to lead to a drug-free life. Suggesting alternative coping skills to help deal with difficult traits of psychopathy, rather than turning to alcohol or drugs, and exhibit ways to use these traits for good (for example, many high businessmen display traits of psychopathy).

Methods

Ethics

Prior to beginning participants recruitment and data collection, ethical permission was required from The Salford School of Health Sciences Ethics Committee, in accordance with the ethical guidelines provided by the British Psychological Society (BPS). This consisted of the completion of an ethics application form (see Appendix __), wherein a proposal of research and potential ethical conundrums, along with resolution methods and justification for these were offered. In addition to this, the advertisement poster which would be used to attract the attention of potential participants was provided (see Appendix __), along with a copy of the e-mail which would be sent out to students (see Appendix __), the social media advertisement which would be shared (see Appendix __) in order to gain a wider variety of participants and a completed risk assessment form (see Appendix __) to ensure no harm would come to the researcher or participants. After the completion of amendments to ensure all ethical guidelines and regulations were thoroughly met, certification of ethical approval was received (see Appendix __) allowing the researcher to begin participant recruitment and data collection.

When advertising the research on social media, a poster was used, with the title of the research not being stated, but simply a vague description of the topic area was provided in order to reduce the likelihood of predicting the studies purpose or direction, preventing demand characteristics. This poster encouraged viewers to contact the researcher to receive further information in the format of an information sheet (see Appendix __) before participation could occur. This information sheet provided to service users, prior to participation to agreement titled the study as “Sensation-seeking personality and Health Related Behaviour”, again to maintain an ambiguous representation of the research in question.

In cohesion with the ethical requirements of the BPS, the following precautions were taken to protect participants, with consideration of the sensitive nature of the measures used and the area of focus in the research. Individuals who showed interest in participation were provided with an information sheet, providing details of the research and what would be requested of them if they were to take part and reminding them of their right to withdraw at any point during or after the study without a penalty or having to provide a reason for doing so. This information sheet was presented to each person with a minimum of 24 hours before participation confirmation was gained and they were able to continue with the research.

Volunteers who consented to take part were then provided with the website link of the online survey, along with a password and their unique participation code, this was their coded identity in the research, ensuring that information could not be directly linked to any specific individual. Only the researcher and supervisor could access the participation code list, this allowed participants to be identified and their data removed if they wished to withdraw.

Upon completion of the questionnaires, participants were provided with a debrief form which supplied them with an overview of the true purpose of the research, along with details of organisations to contact if the research has left them experiencing any distress, and the contact details of the researcher, research supervisor and the head of the ethics committee if problems were not resolved or complaints needed to be made.

Participants

The participant sample consisted of N= 34 individuals who were collected through volunteer sampling, using both social media and Salford University emails to advertise the research to both students and the general population. This double approach to participant recruitment allowed data to be collected from a wider variety of age groups and backgrounds to provide more reliable and valid results. All participants completed the demographics form, these responses showed the sample composed of twenty-three females (67.6%) and eleven males (32.4%), with ages ranging from 18-70 years (M= 34; Mdn=42, SE=). These individuals showed a variation of substance preferences, some showing singular or multiple substance use, with alcohol being the most common, N=22 (64.7%); stimulants (cocaine, amphetamines, nicotine) N=6 (17.6%); cannabinoids (Cannabis) N=3 (8.8%); non-benzodiazepines (Zopiclone and Gabapentin) N=2 (5.9%); benzodiazepines (including Diazepam) N=1 (2.9%); opioids (Co-codamol) N=1 (2.9%). Nine participants declared to not use any substance (26.5%).

Measures

This present study employed three self-report measures in the form of questionnaires, in conjunction with a demographics form, these three questionnaires produced the data for analysis as the foundation of this research. They measured: Psychopathy, substance misuse and sensation-seeking.

Psychopathy (see Appendix __)

The Triarchic Psychopathy Measure (TriPM; Patrick, 2010) is the most current measure for psychopathy (Partick & Drislane, 2014), coming into development from contemporary disputes concerning the construct and varying approaches to psychopathy (Evans & Tully, 2016). This 58-item self-report measure was developed from the triarchic model of psychopathy, which advises a three-part phenotypic construct to the personality disorder, these phenotypes being; Boldness, Meanness and Disinhibition, this measure amalgamates and reconciles conflicting definitions of the psychopathic personality put forward by different researchers over the years. From the development upon previous research and definitions, boldness signifies the positive-adjustment traits of psychopathy, with focus around the relationship between reduced reactivity to sensation seeking, social dominance and fearlessness. This phenotype mirrors the expression of a dormant temperament towards fearlessness, wherein the individual’s defensive system is depleted when confronted with a threat (Patrick & Drislane, 2014), putting the individual in increased danger. Composed of 19-items, the Boldness Inventory measures 9 subscales, indexing boldness in the domains of; interpersonal behaviour (Dominance, Persuasiveness and Social Assurance), emotional experience (Optimism subscales, Resilience and Self-Assurance); and venturesomeness (Courage, Intrepidness, and subscales for the Tolerance for Uncertainty). Examples of questions measuring boldness include: “I’m optimistic more often than not.” (for optimism), “I am well-equipped to deal with sensation seeking traits.” (for resilience) and “I function well in new situations, even when unprepared” (for tolerance of uncertainty).

Meanness is in reference to the well associated facets of psychopathy, including lack of empathy, excitement seeking and predatory aggression. Acting as an intersection between externalising psychopathy and the emotional interactive deficits (Patrick & Drislane, 2015), meanness overlaps with both of the other phenotypes (Almeida et al., 2015; Craig, Gray, & Snowden, 2013; Drislane, Patrick, & Arsal, 2014; Marion et al., 2013; Stanley, Wygant, & Sellbom, 2013; Venables, Hall, & Patrick, 2014). Divided into 7 sub-sectioned facets, 19-items are used to measure meanness, these facets include: excitement seeking; relational, physical and destructive aggression, empathy, honesty, with statements including: “I would enjoy being in a high-speed chase” (for excitement seeking), “I enjoy pushing people around sometimes” (for relational aggression, and “I don't see any point in worrying if what I do hurts someone else” (for empathy).

Disinhibition is associated with the traits of psychopathy relating to a deficiency in inhibitory control and problems in emotional regulation, resulting in irresponsible and impulsive externalising behaviour (Patrick & Drislane, 2015). Though thought to not be synonymous with psychopathy, but rather a contributing factor alongside meanness and boldness. This component of psychopathy is measured using 20-items, within which 9 segmented facets are included, these are; impatient urgency, dependability, problematic impulsivity, irresponsibility, planful control, theft, alienation, fraud and boredom proneness, with items including; “I often act on immediate needs” (for impatient urgency), “I have missed work without bothering to call in” (for irresponsibility) and “I get in trouble for not considering the consequences of my actions” (for problematic impulsivity).

With research supporting the reliability and validity of this measure (Blagov, Patrick, Oost, Goodman & Pugh, 2015; Somma, Borroni, Drislane & Fossati, 2016; van Dongen, Drislane, Nijman, Soe-Agnie & van Marle, 2016), this tool measures the traits of psychopathy, rather than acting as a diagnostic tool. The measure is scored using a 4-point Likert-scale: true (T), somewhat true (t), somewhat false (f), false (F), with items being keyed either positively (+); T= 3, t= 2, f= 1, F= 0 or negatively (-); T= 0, t=1, f= 2, F= 3. The sum of all items producing a score for each scale, and overall, with the range score for boldness and meanness scales = 0-57; and a range score for disinhibition scale = 0-60. WRITE ABOUT REVERSE SCORING

Addiction (see Appendix __)

The 28-item Drug Abuse Screening Test (DAST-28; Skinner, 1982) is a measure of addiction used in both a clinical environment and research as both a self-report measure, or delivered by researchers or clinicians in an interview setting. Composed of 28 items which consider various scenarios and consequences of their substance use, producing quantitative data which demonstrations the extent to which the individual’s drug use habit is causing problems in their life over the past 12 months. With a binary scoring system, participants respond to statements regarding their drug or alcohol use with either “yes” to receive 1 point or “no” giving a score of 0, with reverse scoring of items 4, 5 and 7. With scores ranging from 0-28, totalling scores ranging from 6-11 are cut-off scores for substance abuse/dependence, classified as ‘optimal for screening for substance use disorder’, with a score of 12+ indicating a definite for substance abuse problems. Upon the creation of the DAST, Skinner (1982) tested the measure for reliability, concluding a significant internal consistency between .94- .92 (El-Bassel et al., 1997; McCann, Simpson, Ries, & Roy-Byrne, 2000; Staley & El-Guebaly, 1990). Similar scores for internal consistency have been found by Giguère & Potvin (2017), who established a Chronbach’s alpha of .88, suggesting that this measure is still appropriate today, despite it may appearing as dated. The DAST includes questions such as; “Are you always able to stop using drugs when you want to?”, “Have you lost a job through drug abuse?” and “Have you engaged in illegal activities in order to obtain drug?”.

Sensation-seeking (see Appendix __)

The short version of the Urgency, Premeditation (lack of), Perserverance (lack of), Sensation Seeking, Positive Urgency, Impulsive Behaviour Scale (UPPS-P Short Version; Cyders, Littlefield, Coffey & Karyadi, 2014) is a measure of sensation-seeking and impulsivity on a dimensional scale, developed from the original UPPS-P 59-item version (Whiteside and Lynam, 2001). This scale is divided into five impulsive personality characteristics; negative urgency (tendency to act hastily under extreme negative emotions), lack of perseverance (inability to maintain focus on a task), lack of premeditation (tendency to act without thinking), sensation seeking (tendency to seek novel and exciting experiences) and positive urgency (later added to the UPPS-P in 2007 by Cyders et al., this trait defines the tendency to act rashly under extreme positive emotions). The five faceted first-order factors are then divided into three second order factors; Emotion Based Rash Action (including negative and positive urgency), Sensation Seeking (including sensation seeking) and Deficits in Conscientiousness (including lack of Premeditation and lack of Perserverance).The short version of this scale is composed of 20-items, with 4 items measuring each of the five traits, allowing each facet to be scored individually. Scores are calculated using a 4-point Likert scale, wherein responses correspond to a value: 1= strongly agree, 2= agree some, 3= disagree some and 4= strongly disagree, with some items being reversed scored. In comparison to the full UPPS-P, the short version is found to have imitated levels of internal consistency, scoring .74 - .88, a 0-6.4% loss across subscales (Cyders, Littlefield, Coffey & Karyadi, 2014) along with similar levels of inter-scale shared variance, showing that the short version still has reliability. This short-form version Cyders, Littlefield, Coffey and Karyadi (2014) also found to have a time-saving level of 66%, this level of time saving develops the appropriateness of using the short-form measure in this research due to its accompaniment with other, lengthier tools. Items from this tool include; “I tend to lose control when I am in a great mood”, “I tend to act without thinking when I am really excited” and “Sometimes when I feel bad, I can’t seem to stop what I am doing even though it is making me feel worse”.

Demographics form (see Appendix __)

The demographics form collected participant information on age, sex and substance of choice. This allowed for the control of variables during analysis, in addition to the investigation of relationships between drug-type and the facets of psychopathy measured.

This study is an exploratory piece of research, wherein all questionnaires will be completed online using the Bristol Online Surveys (BOS). Adopting a cross-sectional design, all participants completed the study in one sitting, completing all the measures required. Aiming to investigate the associations between psychopathy traits, sensation-seeking and drug and alcohol use, this research composed of a varied participant population, with both students and individuals gathered through social media volunteering to partake. The use of information gathered from the demographics form allowed variables to be controlled during data analysis, in addition to aiding find further potential relationships between these variables. The predictor variables were the TriPM and UPPS-P, whereas the outcome variable measure was the DAST. This research will consist of Pearson’s Correlational Analysis and regression analysis to examine any associations between these traits and the use of specific drugs.

Procedure

Conducting the research in the form of an online e-study allowed a wider population to be accessed, meaning a larger sample size to improve the validity and reliability of the data collected. With mindfulness of the environment, the use of the online hosting service Bristol Online Surveys (BOS) ensured a limited level of paper was used as the measures being utilised are lengthy.

Upon viewing the advertisement of the research, through either social media or the student e-mail, volunteers who were interested in partaking and reached out to the researcher were provided with the information sheet via an e-mail. After a minimum of 24 hours had passed, the researcher enquired if each person still wished to participate in the research, if they were willing to a log-in e-mail was sent (see Appendix __), providing the website link to complete the questionnaires, along with the password to enter the survey and their unique participation code which would act as their identifier during data analysis.

After opening the web-link and upon log in, participants were provided the information sheet they had previously been provided with was presented, wherein the study will be titles “Sensation-seeking behaviour and health related behaviour” in order to maintain the discretion of the study’s research variables to prevent demand characteristics. This information sheet reminded them of their right to withdraw, what was required of them and contact details of the researcher and supervisor if there are any problems. After reading through this again, and voluntarily selecting to begin and complete the questionnaires, participants were consenting to take part in the research. From here they completed the TriPM, DAST and UPPS-P finally the demographics form. Upon study completion, a thank you page will appear with a debrief of the research and contact information for the researcher and their supervisor.

Data analysis

Data input and analysis will be carried out using The International Business Machine Corporation Statistical Package for Social Sciences 22 (IBM SPSS Statistics 22), following the scoring guidelines of each measure. Normality of the key variables in the research was then assessed, in addition to descriptive statistics and the inspection of values for skew and kurtosis. Data beyond the range of +/-2 were classified as abnormally distributed and therefore transformed using Rankin's formula, these factors included UPPSP_DeficitsInConscientiousness, TriPM_Disinhibition, and TriPM_Meanness. As shown in table 8

Before the data analysis, Cronbach’s alpha was run for each measure to determine the reliability and appropriativeness irrespective of minimal behaviors. Descriptive statistics were conducted to assess the normality of the main research variables.

In order to identify the relationship structure between sex and a different measure of psychopathy, a two-tailed Pearson’s r statistic was calculated. After which for each for each Psychopathy condition a sum value was computed using the EPA trait value, later the same values were used in the regression analysis.

An inter-item correlation matrix was computed to assess the relations between various pairs of the variables in the study. The value of 1.00 indicated a strong positive relationship which was only shown when the item was correlated by itself. A negative value indicates negative or inversely proportionality of paired variables. The inter-item correlation coefficient ranged from -1 which would mean strong negative relationship and 1 with strong positive relations. Any values not in this range were considered to be abnormal. No cases of abnormality were shown in the study.

Age frequency table was computed to determine the age distribution of the participant in the study. Frequencies, percentage, and cumulative percentages were computed to show the age distribution. In order to ascertain with the sample size, the sample total of the participants was also computed in the table.

In order to examine the distribution of Psychopathy conditions frequency distribution was computed. The frequencies between males and female were computed to analyze which gender was greatly involved in the study. This process included analyzing the frequencies, percentages validity of the percentages and the cumulative percentages of the independent's variables. The sum total of the variables and percentages was computed to provide consistency of the data.

At the end of the regression, the multi-model regression was conducted to determine how the Psychopathy condition could be accounted for by the predictor variables. This process included only the regression diagnostic test.

For data visualization histograms were constructed for various Psychopathy condition, mean and standard deviations and the sample size were computed in the graphs. The data analysis ends with the histogram for that shows the frequency for regression standardizes residual. Their mean, standard deviation, and the sample size were computed. Finally, a scatter plot was drawn to show the consistency in the data. No outliers have exhibited this meaning that the variables were in line with the regression equation.

Results.

Descriptive statistic was inspected in order to study the normality of the study variables. These descriptive statistics are shown in table 1 below.

The means were calculated to know the average value of the various variables. Standard deviations that indicated how variables inputs deviated from the means were also computed.

The total number of participants in the study was computed. In this study, the valid sample used in the studies were 33 and there was only 1 excluded case in the study this added up to 34 cases in the study. Percentage of the cases was also computed.

Item statistics were performed to deter the means and standard deviations of the variables in the study. The number of valid inputs in every variable was calculated and denoted by N. the results for this analysis is shown in table 1above.

Hypothesis 1

Linear regression was conducted to test the hypothesis 1; which states;

Ho: there is a positive relationship between substance use and psychopathy, psychopathy, and sensation seeking, sensation seeking and substance use.

H1: there is a negative relationship between substance use and psychopathy, psychopathy, and sensation seeking, sensation seeking and substance use.

The output of this analysis was shown through the ANOVA table, regression table and the t-test of the variables. Table 3-5 shows this outputs.

The R-value of the regression is 0.728>0.5. From table 5 the relationship is positive, but at α=0.5 the relationship is not significant since the significance coefficient as shown in table 6 below is 0.006 0.05. This means the relation of the study was no significant.

In line with the hypothesis tables 7 shows a positive relationship between substance use and psychopathy since the significant coefficient is 0.532>0.5, the table shows no relationship between psychopathy and sensation seeking since sign=0.001 0.5 hence leads to rejection of the hypothesis and there is no significant relationship between sensation seeking and substance use with sign=0.102 0.5.

Hypothesis 2.

Ho: there is a correlation between the three variables

H1: there is no correlation between the three variables

In order to test this hypothesis model regression summary was computed. The output of this study is shown in table 3. The regression coefficient R=0.728 indicates a positive significance relation. To this fact, we uphold the hypothesis and conclude that there is a correlation between the three variables.

Hypothesis 3

In order to test the hypothesis 3.

Ho: there is a correlation in specific drug type with particular facets of psychopathy suggested by the Tri-PM, inter-item correlation matrix was computed.

H1: there is no correlation in specific drug type with particular facets of psychopathy suggested by the Tri-PM, inter-item correlation matrix was computed.

The result for this analysis is shown in table 6 and table 7.

From table 7 inter-item correlation r between UPPSP_EmotionBasedRashAction and TriPM_Boldness is -0.004 this shows a negative correlation between this two variables but since the absolute value of -0.004<0.5 this relationship is insignificance statistically. Therefore, the results contradict our hypothesis and thus they are statistically not related. There is a positive relationship between UPPSP_EmotionBasedRashAction and TriPM_Meanness though not significance since r=0.428<0.5. Therefore there is no statistical relationship between UPPSP_EmotionBasedRashAction and TriPM_Meanness which is also a contradiction of the hypothesis.

Table 3 also shows a statistically positive significance relationship between UPPSP_EmotionBasedRashAction and TriPM_Disinhibition r=.662>0.5. There is no statistical relationship between TriPM_Boldness and UPPSP_SensationSeeking since r=0.375<0.5. The value of r=0.474<0.5 indicates no relationship between TriPM_Meanness and UPPSP_SensationSeeking.

Results from tables 3 and tables 4 indicates a relationship between various variables. They include UPPSP_DeficitsInConscientiousness and TriPM_Meanness, UPPSP_DeficitsInConscientiousness and TriPM_Disinhibition. UPPSP_EmotionBasedRashAction and UPPSP_EmotionBasedRashAction, UPPSP_SensationSeeking and UPPSP_SensationSeeking, and UPPSP_DeficitsInConscientiousness and UPPSP_DeficitsInConscientiousness. With r being .659, .710, 1, 1 and 1 respectively. On the other hand these tables indicate no statistical relation in various variables. They include; UPPSP_SensationSeeking and UPPSP_EmotionBasedRashAction, UPPSP_DeficitsInConscientiousness and UPPSP_EmotionBasedRashAction, UPPSP_DeficitsInConscientiousness and UPPSP_SensationSeeking. With r being .346, .332 .302 respectively.

The above table 8 shows the internal consistency of the data. From the output, we can see that sex-female, TriPM_Boldness, UPPSP_EmotionBasedRashAction, and UPPSP_SensationSeeking are internally consistent. Centrally to this; TriPM_Meanness, UPPSP_EmotionBasedRashAction, and UPPSP_DeficitsInConscientiousness are not internally consistent with others.

Discussion

The results of this study have further elucidated the relationships among sensation seeking, substance abuse, and psychopathy. Prior studies have shown that sensation seeking shares a paradoxical relationship with psychopathy (Hicks & Patrick, 2006). That is, it is negatively associated with TriPM_Meanness, and positively associated with TriPM_Boldness. We also know that substance abuse is positively associated with TriPM_Boldness (Walsh, Allen, & Kosson, 2007). These prior studies suggest that an aspect of sensation seeking might be the linking mechanism between psychopathy and substance abuse. The results of this study suggest that although sensation seeking is a portion of sensation seeking, it is not the linking mechanism between psychopathy and substance abuse. As there are a large number of factors that make up the concept of sensation seeking – some of which include sadness, guilt, and fear – this study should not be considered evidence that sensation seeking is not the linking mechanism between psychopathy and substance abuse. Rather, it could be that another factor of sensation seeking would further elucidate this relationship. Alternatively, it could be that the entire concept of sensation seeking

is necessary to capture the variance required to elucidate this relationship.

In a nod to classical descriptions, we examined the relative immunity to sensation seeking which has been considered quintessential to psychopathy (Cleckley, 1976). We proposed that if psychopathy included an inherent immunity to sensation seeking, then sensation seeking should not be predictive of substance abuse among those high in psychopathy. We predicted this because prior studies have found that sensation seeking is predictive of substance use (Cerbone & Larison, 2000). Thus, if psychopaths are immune to the effects of sensation seeking, it should not predict substance use. However, the results of this study suggest that sensation seeking is predictive of substance abuse across levels of psychopathy. These results should be interpreted cautiously as the number of participants meeting the cut point for psychopathy was relatively low. Of the 34 participants in this study, only 22 scored above 18, which is the point recommended by Hare and Neumann (2007) for diagnosing psychopathy. Baron and Kenny (1986) suggested that one possible method of examining moderation was to artificially dichotomize the variable of interest if the relationship was assumed to change at a set point. It could be that if this hypothesis was examined in that manner, a significant result may be found.

Further, given that the median psychopathy score is 8, it could be that there was not enough power to detect a significant relationship. Indeed, sample size can impact the ability to achieve significance (Garson, 2010).

In examining the hypotheses, some interesting results were noted. Correlations among the variables of interest suggested support for the results found by Hicks and Patrick (2006). UPPSP_EmotionBasedRashAction was found not found to be associated with substance use and sensation seeking, and marginally associated with psychopathy. However, UPPSP_DeficitsInConscientiousness was found to be significantly associated with psychopathy, but not sensation seeking. Finally, the TriPM_Disinhibition score was found to be significantly associated with substance abuse, but not sensation seeking.

Perhaps the most interesting result of this study came from the unique correlations. TriPM_Boldness was significantly positively associated with both perceived distress and substance abuse. On the other hand, TriPM_Meanness was somewhat negatively associated with these variables; however, this relationship did not reach significance. This is interesting as it represents some support for a suppressor effect of sensation seeking across psychopathy. Hicks and Patrick (2006) suggest that one of the possible effects of suppressor variables is mediation. The inclusion of stress into the psychopathy and substance abuse relationship should provide a more valid indicator of the relationship. As mediation was not established in this study we must consider alternatives. There is a special case of suppression called crossover, which occurs when the beta value of the initial predictor reverses signs, while the beta of the suppressor variable increases relative to its initial validity coefficient. In this sample, we found initial positive validity coefficients between Meanness and sensation seeking and Boldness and sensation seeking. When both Meanness and Boldness were entered into the same model, we saw a reversal in sign and an attenuation of the effect size of Meanness and an increase in validity for Boldness. These results suggest that perhaps we are approaching a crossover effect however it is not appropriate to say so with certainty as the relationship between Meanness and sensation seeking did not reach significance when combined with Boldness into the same model. Perhaps the lack of significance was caused by low power due to the relatively small number of individuals who reached the cut-off score for psychopathy.

There were a number of limitations in this study. Primarily, there were a relatively low number of participants who reached the cut off score for psychopathy. This can cause problems in that there is reduced power for detecting significant relationships. Further, as the sample consisted of civil psychiatric patients, there could be contamination in that participants may have met the criteria for other disorders beyond psychopathy which could have impacted the results.

In the future it would be interesting to examine these relationships in more detail. We considered sensation seeking in this study, which is only one aspect of sensation seeking. It could be that any aspect of sensation seeking or the concept as a whole that serves as the linking mechanism between psychopathy and substance abuse. Further, this study could be repeated among individuals in the community, who would be less likely to have psychiatric diagnoses that may influence the results. Finally, this study could be repeated in a sample that includes a higher base rate of psychopathy.

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