Are all drug addicts impulsive? Effects of antisociality and extent of multidrug use on cognitive and motor impulsivity.
ABSTRACT The purpose of this investigation was to examine the influence of antisociality and extent of multidrug use on cognitive and motor impulsivity among substance-dependent individuals (SDIs) that used primarily cocaine and/or heroin. One hundred currently abstinent male SDIs participated in the study. Extent of multidrug use and degree of antisociality, assessed with the Socialization Scale of the California Psychological Inventory (So-CPI), were used to classify participants into one of four groups: high antisocial/low multidrug use, high antisocial/high multidrug use, low antisocial/low multidrug use, and low antisocial/high multidrug use. All subjects completed the Iowa Gambling Task to assess cognitive impulsivity and the Stroop Task to measure motor impulsivity. Contrary to expectations, antisociality was associated with more advantageous performance on the Iowa Gambling Task, independent of extent of multidrug use. In contrast, greater multidrug use was associated with general psychomotor slowing on the Stroop Task. Results suggest that a subclinical form of antisociality may have a paradoxically facilitating effect on decision-making and cognitive impulsivity among SDIs.
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ABSTRACT: Contemporary studies evidence that antisocial behavior of children and adults is associated with neuropsychological deficits of four types: 1) relatively low general intelligence; 2) deficit of verbal intelligence; 3) prefrontal dysfunction; 4) deficit of activation of limbic structures. In most cases the antisocial behavior is a consequence of brain underdevelopment due to effects of poor social environment. Nevertheless, heritability and dysfunction of catecholaminergic innervation predispose to antisocial behavior even when the social environment is favorable.Sozialnaya i Klinicheskaya Psikhiatria. 08/2013; 23(4):83-90.
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ABSTRACT: The multidimensional construct of impulsivity is implicated in all phases of the addiction cycle. Substance dependent individuals (SDIs) demonstrate elevated impulsivity on both trait and laboratory tests of neurobehavioral impulsivity; however our understanding of the relationship between these different aspects of impulsivity in users of different classes of drugs remains rudimentary. The goal of this study was to assess for commonalities and differences in the relationships between trait and neurobehavioral impulsivity in heroin and amphetamine addicts. Participants included 58 amphetamine dependent (ADIs) and 74 heroin dependent individuals (HDIs) in protracted abstinence. We conducted Principal Component Analyses (PCA) on two self-report trait and six neurobehavioral measures of impulsivity, which resulted in two trait impulsivity (action, planning) and four neurobehavioral impulsivity composites (discriminability, response inhibition efficiency, decision-making efficiency, quality of decision-making). Multiple regression analyses were used to determine whether neurobehavioral impulsivity is predicted by trait impulsivity and drug type. The analyses revealed a significant interaction between drug type and trait action impulsivity on response inhibition efficiency, which showed opposite relationships for ADIs and HDIs. Specifically, increased trait action impulsivity was associated with worse response inhibition efficiency in ADIs, but with better efficiency in HDIs. These results challenge the unitary account of drug addiction and contribute to a growing body of literature that reveals important behavioral, cognitive, and neurobiological differences between users of different classes of drugs.Addictive behaviors 12/2013; · 2.25 Impact Factor
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ABSTRACT: Substance dependent individuals (SDI) often exhibit decision-making deficits; however, it remains unclear whether the nature of the underlying decision-making processes is the same in users of different classes of drugs and whether these deficits persist after discontinuation of drug use. We used computational modeling to address these questions in a unique sample of relatively “pure” amphetamine-dependent (N = 38) and heroin-dependent individuals (N = 43) who were currently in protracted abstinence, and in 48 healthy controls (HC). A Bayesian model comparison technique, a simulation method, and parameter recovery tests were used to compare three cognitive models: (1) Prospect Valence Learning with decay reinforcement learning rule (PVL-DecayRI), (2) PVL with delta learning rule (PVL-Delta), and (3) Value-Plus-Perseverance (VPP) model based on Win-Stay-Lose-Switch (WSLS) strategy. The model comparison results indicated that the VPP model, a hybrid model of reinforcement learning (RL) and a heuristic strategy of perseverance had the best post-hoc model fit, but the two PVL models showed better simulation and parameter recovery performance. Computational modeling results suggested that overall all three groups relied more on RL than on a WSLS strategy. Heroin users displayed reduced loss aversion relative to HC across all three models, which suggests that their decision-making deficits are longstanding (or pre-existing) and may be driven by reduced sensitivity to loss. In contrast, amphetamine users showed comparable cognitive functions to HC with the VPP model, whereas the second best-fitting model with relatively good simulation performance (PVL-DecayRI) revealed increased reward sensitivity relative to HC. These results suggest that some decision-making deficits persist in protracted abstinence and may be mediated by different mechanisms in opiate and stimulant users.Frontiers in Psychology 08/2014; · 2.80 Impact Factor
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Are all drug addicts impulsive? Effects of antisociality and extent
of multidrug use on cognitive and motor impulsivity
Jasmin Vassilevaa,⁎, Raul Gonzaleza, Antoine Becharab, Eileen M. Martina,c
aDepartment of Psychiatry, University of Illinois – Chicago, Chicago, IL 60622, USA
bDepartment of Psychology, University of Southern California, Los Angeles, CA 90089, USA
cJesse Brown Veterans Administration Medical Center, Chicago, IL 60622, USA
The purpose of this investigation was to examine the influence of antisociality and extent of multidrug use on
cognitive and motor impulsivity among substance-dependent individuals (SDIs) that used primarily cocaine and/or
heroin. One hundred currently abstinent male SDIs participated in the study. Extent of multidrug use and degree of
antisociality, assessed with the Socialization Scale of the California Psychological Inventory (So-CPI), were used
to classify participants into one of four groups: high antisocial/low multidrug use, high antisocial/high multidrug
use, low antisocial/low multidrug use, and low antisocial/high multidrug use. All subjects completed the Iowa
Gambling Task to assess cognitive impulsivity and the Stroop Task to measure motor impulsivity. Contrary to
expectations, antisociality was associated with more advantageous performance on the Iowa Gambling Task,
independent of extent of multidrug use. In contrast, greater multidrug use was associated with general psychomotor
slowing on the Stroop Task. Results suggest that a subclinical form of antisociality may have a paradoxically
facilitating effect on decision-making and cognitive impulsivity among SDIs.
© 2007 Elsevier Ltd. All rights reserved.
Keywords: Drug addiction; Impulsivity; Antisocial; Polysubstance use; Multidrug use; Decision-making
Impulsivity is a multidimensional construct, considered a core component in drug addiction (Goldstein
and Volkow, 2002). Reward-discounting or cognitive impulsivity refers to the preference for smaller
immediate rewards over larger delayed rewards, whereas rapid-response or motor impulsivity is manifested
Addictive Behaviors 32 (2007) 3071–3076
⁎Corresponding author. Department of Psychiatry (MC 912), University of Illinois – Chicago, 1601 West Taylor Street,
Chicago, IL 60612, USA. Tel.: +1 312 413 0149; fax: +1 312 413 8147.
E-mail address: email@example.com (J. Vassileva).
0306-4603/$ - see front matter © 2007 Elsevier Ltd. All rights reserved.
Author's personal copy
Garcia and Perez-Garcia, 2007). However, not all SDIs manifest such impairments, which suggests that
study explored whether two potential risk factors, namely antisociality and extent of multidrug use, both
commonly observed in SDIs (Craig, 2000; Leri et al., 2003) and previously related to poor impulse control
SDIs. We used the Iowa Gambling Task (IGT) and the Stroop Task: two common laboratory paradigms to
be associated with greater impulsivity in SDIs.
Participants were 100 currently abstinent, HIV seronegative male participants with history of substance
dependence, enrolled in a larger study of neurocognition and HIV among SDIs at the University of
Illinois, Chicago. Subjects testing positive on urine toxicology screening or breathalyzer testing for
alcohol, or with any history of potentially confounding neurologic illness or injury, schizophrenia, or
current alcohol abuse or dependence were excluded.
History of substance abuse and dependence was determined using the Structured Clinical Interview for
DSM-IVSubstanceAbuse Module(Firstetal., 1996). Antisocialitywas assessed bytheSocializationScale
of the California Psychological Inventory (So-CPI; Gough, 1987), a common measure of antisociality
among non-incarcerated individuals. We used the North American Adult Reading Test (Grober and
Sliwinski, 1991) to estimate verbal IQ.
All participants had a positive history of cocaine dependence and 80% carried a diagnosis of past
alcohol abuse or dependence. Subjects diagnosed additionally with opiate dependence (53% of the
sample) were classified as “high multidrug use”, while all others were assigned to the “low multidrug use”
group. Participants were further appointed to a “high” or “low antisocial” group based on a median split
(Md=27) of their So-CPI scores. With the exception of a positive hepatitis C serostatus [χ2=4.02,
Demographic and substance use characteristics
Y drug use
D last use
80 (31, 304)
21.31 (3.50 )
82.5 (36.5, 287)
115 (60.5, 195)
90 (30, 240)
So-CPI – Socialization Scale of the California Psychological Inventory; Y drug use – years of drug use; D last use – number of
days since last used drugs.
3072J. Vassileva et al. / Addictive Behaviors 32 (2007) 3071–3076
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pb0.04], the four groups were well matched on demographic and substance dependence characteristics
All subjects completed the computerized IGTand the Reaction Time (RT) Stroop Test (see Bechara et
al., 2001; Martin et al., 1992 for detailed descriptions). The IGTrequires subjects to select a series of cards
from one of four decks. Each card carries a monetary gain or loss of varying size. Patients with
ventromedial prefrontal lesions and SDIs often perform the task poorly, by persistently choosing cards
associated with large rewards but also with larger and more frequent losses. The computerized RT Stroop
requires subjects to name the display color of a series of colored words under three conditions with
varying demands on behavioral inhibition. The most taxing condition (i.e. the “incongruent condition”)
Fig. 2. Interaction between extent of multidrug use and trial block on the Iowa Gambling Task.
Fig. 1. Main effect of antisociality on Iowa Gambling Task.
3073J. Vassileva et al. / Addictive Behaviors 32 (2007) 3071–3076
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requires subjects to name color-discordant words (e.g. “RED” presented in green) while suppressing the
tendency to read the word.
IGT data were scored according to the procedure first reported by Bechara et al. (2001). Data were
analyzed with a mixed-model ANOVA, with trial block as the within-subject factor, and Multidrug Use
and Antisociality as the between-subjects factors. As expected, all groups improved their performance as
the task progressed [F(4,380)=10.93, pb0.0001]. However, contrary to expectations, higher levels of
antisociality were associated with better IGT performance overall [F(1,95)=5.17, pb0.02] (Fig. 1).
Additionally, IGTscores for subjects in the “low multidrug use” group showed a significant improvement
in performance over the 100 trials, whereas the subjects in the “high multidrug use” group showed no
evidence of improved performance as the task progressed, indicated by a significant interaction between
Trial Block and Multidrug Use [F(4,380)=2.77, pb0.02] (Fig. 2).
ANOVA.1All participants' reaction times increased with increasing demands on response inhibition [F
(2,158)=279.2; pb0.0001]. The “high multidrug use” group was significantly slower (M=814.95±21.19)
than the “low multidrug use” group (M=749.66±21.95) in all Stroop conditions [F(1,79)=4.58, pb0.03]
(Fig. 3); however, this group difference was no longer apparent when hepatitis C serostatus was controlled.
To our knowledge, this is the first study to investigate specifically the effects of antisociality and extent
of multidrug use on indices of impulsivity among SDIs. The study revealed three important findings. First
and foremost, contrary to predictions, we found that antisociality was associated with more advantageous
Fig. 3. Main effect of extent of multidrug use on the Stroop Color Word Task.
1Due to technical difficulties with the computer program, we had missing data from 18 subjects (valid n=88).
3074J. Vassileva et al. / Addictive Behaviors 32 (2007) 3071–3076
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decision-making performance on the IGT and thus with better cognitive impulse control, independent of
extent of multidrug use. Second, there was indication of a significant improvement in decision-making
performance across IGT trial blocks for the low multidrug use but not for the high multidrug use group,
evidenced by a flatter learning curve in the high multidrug use group. Finally, greater extent of multidrug
usewas associatedwithgeneral psychomotor slowing,butnotwith motorimpulsivity perse on the Stroop
In light of our earlier finding that psychopathic heroin addicts evidence impaired performance on the
IGT (Vassileva et al., 2007), current results suggest that impaired performance of antisocial individuals on
the IGT may become evident only at the extreme end of the antisocial spectrum, when antisociality is a
clinically diagnosable syndrome such as Antisocial Personality Disorder or Psychopathy, and not when it
is manifested as a personality trait considered to be on a continuum with normality, such as degree of
socialization as assessed by the So-CPI. One might thus speculate that a sub-clinical, “non-malignant”
form of antisociality might exert a paradoxically facilitating effect on decision-making and cognitive
impulsivity in SDIs. This will have to be investigated further by future studies. Also, the fact that
antisociality had no effect on motor impulsivity indexed by the Stroop task, but in contrast had a
facilitating effect on decision-making/cognitive impulsivity may be related to better impulse control in the
antisocial group particularly when rewards are involved.
With regards to our second finding, the flatter learning curve of the high multidrug use SDIs suggests
that they do not learn the task contingencies and show greater tendency to perseverate on making
decisions that were initially rewarding, but ultimately disadvantageous. Relative to the high multidrug use
SDIs, our low multidrug use group was guided initially to a greater degree by the higher magnitude of the
immediate rewards. Yet, they learned to shift their strategy as soon as the first punishment trials were
delivered. In contrast, the high multidrug use subjects continued to be guided by the prospect of
immediate short-term gains, and never changed their selection strategy throughout the task.
Finally, the significance of the overall slowing in the high multidrug use group on the Stroop Task
remains unclear, because additional analyses revealed that differences in Stroop reaction times were found
to be accounted for by hepatitis C serostatus. This is consistent with a recent report from our laboratory
(Martin et al., 2004) indicating that a positive hepatitis C serostatus is associated with overall slower
information processing on the Stroop task, and deserves further investigation.
We thank Joanna Jacobus, Stephanie King, and Niles Rains for their assistance with data collection.
This research was supported by NIDA grants R21-DA18086 (JV), R01-DA12828 (EMM) and F32-
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