Impulsivities and addictions: Similarities and differences between opiates and stimulants
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1
Virginia Commonwealth University, Psychiatry, United States
Impulsivity is implicated both as an antecedent risk factor and a consequence of drug addiction. However, progress in the field is hampered by the multi-dimensional nature of impulsivity, characterized by multiple personality, psychiatric, and neurocognitive dimensions that are rarely examined concurrently within the same population. Further, our understanding of how the different dimensions of impulsivity are manifested in users of different classes of drugs is limited by the high rates of polysubstance dependence among drug users. To circumvent these methodological challenges, we have developed a program of addiction research in Bulgaria, where we have access to mono-substance dependent (‘pure’) heroin and amphetamine users. We administered a comprehensive battery of neurocognitive tasks of ‘impulsive choice’ (Iowa Gambling Task, Cambridge Gambling Task, Delayed Reward Discounting Task, Balloon Analogue Risk Task) and ‘impulsive action’ (Immediate Memory Task, Go/No-Go Task, Stop Signal Task); self-report personality measures of trait impulsivity and related traits (Barratt Impulsiveness Scale-11, UPPS Impulsive Behavior Scale, Buss Warren Aggression Questionnaire, Levenson’s Self-Report Psychopathy Scale); and psychiatric indices of impulsivity (ADHD, conduct disorder, antisocial personality disorder, psychopathy). Participants included ‘pure’ heroin-dependent individuals (HDI), ‘pure’ amphetamine-dependent individuals (ADI), polysubstance-dependent individuals (PDI), and non-substance dependent healthy controls (HC). The majority of substance dependent participants were in protracted abstinence at the time of testing. Our goal was to explore which dimensions of impulsivity are common across addictions and which are unique to specific classes of drugs, such as opiates and stimulants.
Our results reveal important differences between opiate and stimulant addictions. Specifically, computational modeling analyses of the Iowa Gambling Task, one of the most widely used tasks of decision-making, revealed that impaired decision-making in ADI is mediated by hypersensitivity to reward, whereas impaired decision-making of HDI is driven by hyposensitivity to loss. Further, machine-learning analyses revealed substance-specific multivariate impulsivity profiles that classified HDI and ADI in new samples with high degree of accuracy. Out of 54 predictors in the machine-learning model, psychopathy was the only predictor that was common to both opiate and stimulant addictions. Notable dissociations emerged between factors predicting opiate vs. stimulant dependence, which often showed opposite patterns between HDI and ADI. Impulsivity dimensions were also differentially associated with HIV risk behaviors in HDI and ADI. Overall, our findings challenge the unitary account of drug addiction and suggest that opiate and stimulant addictions may be driven by different underlying mechanisms. Results may have important implications for the development of cost-efficient diagnostic tests and personalized prevention and intervention programs for HDI and ADI.
Acknowledgements
Research reported in this publication was supported by the Fogarty International Center and the National Institute on Drug Abuse under award number R01DA021421 to Jasmin Vassileva. We thank Woo-Young Ahn for performing the computational modeling and machine-learning analyses and Georgi Vasilev, Kiril Bozgunov, Rada Naslednikova, Ivaylo Raynov, Elena Psederska, Victoria Georgieva, and Dimitar Nedelchev for assistance with recruitment and testing of study participants.
Keywords:
impulsivity,
addictions,
Opiates,
stimulants,
Decision Making
Conference:
SAN2016 Meeting, Corfu, Greece, 6 Oct - 9 Oct, 2016.
Presentation Type:
Oral Presentation in SAN 2016 Conference
Topic:
Oral Presentations
Citation:
Vassileva
J
(2016). Impulsivities and addictions: Similarities and differences between opiates and stimulants.
Conference Abstract:
SAN2016 Meeting.
doi: 10.3389/conf.fnhum.2016.220.00047
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Received:
01 Aug 2016;
Published Online:
01 Aug 2016.
*
Correspondence:
Dr. Jasmin Vassileva, Virginia Commonwealth University, Psychiatry, Richmond, VA, 23219, United States, jlvassileva@vcu.edu