P.6.d.006 Sex Differences in ‘Impulsive Choice’ and ‘Impulsive
Action’ among Opiate and Stimulant Users in Protracted
Abstinence
1
2
3
4
4
Jasmin Vassileva , Michael J. Wilson , Eileen Martin , Kiril Bozgunov , Georgi Vasilev
1Departments
of Psychiatry and Psychology, Virginia Commonwealth University, Richmond, VA, USA; 2Veterans Affairs Maryland Healthcare System,
Baltimore, MD, USA; 3Department of Psychiatry, Rush University Medical Center, Chicago, IL, USA; 4Bulgarian Addictions Institute, Sofia, Bulgaria
Introduction
Neurocognitive Tasks
•Impulsivity is implicated both as an antecedent risk
factor and as a consequence of drug addiction.
•Impulsivity is multifaceted and has a number of
personality, psychiatric, and neurocognitive
manifestations.
•Neurocognitive impulsivity in particular is a strong
candidate endophenotype for addiction.
•Two broad dimensions of neurocognitive impulsivity:
a)
Cognitive impulsivity / ‘impulsive choice’
b)
Motor impulsivity / ‘impulsive action’
•Emerging literature reveals notable sex differences
in neurocognitive dimensions of impulsivity,
however results with users of different classes of
drugs are mixed
•The unique effects of different classes of drugs
among male and female drug users are not well
characterized due to the high rates of
polysubstance use
•To address this difficulty, the study was conducted
in Bulgaria, where we have access to populations of
mono-substance-dependent opiate (heroin) and
stimulant (amphetamine) users as well as
polysubstance users.
Cognitive Impulsivity /
‘Impulsive Choice’
Results
Aims
1.
Are there neurobehavioral differences in
‘impulsive choice’ and ‘impulsive action’
between male and female drug users?
2.
If yes, do these differences vary as a function
of the specific class of drug of abuse
(opiates, stimulants, polysubstance)?
Participants
Age 18-50; IQ>75; No hx psychosis or TBI w/ LOC >30
min; HIV-; negative urine tox screen and breathalyzer
N = 405
Heroin
(H)
Amphetamine
(A)
Polysubstance
(P)
Controls
(C)
F
M
F
M
F
M
F
p
n
64
18
43
25
89
18
96
52
--
Age
31
28
24
24
27
26
25
26
<.001
Est. IQ
103
110
110
109
105
111
109
108
.014
Yrs. Educ.
13
14
13
14
13
14
13
15
<.001
Yrs drug use
Last met heroin
dep. dx (yrs)
Last met amph.
dep. dx (yrs)
DSM-IV Past
Dependence (%)
• Alcohol
• Sedatives
• Cannabis
• Stimulants
• Opiates
• Cocaine
Summary and Conclusions
Significance
Testing
M
Motor Impulsivity /
‘Impulsive Action’
H
n = 82
11.0
5.3
A
n = 68
8.2
--
P
n = 107
10.9
3.2
--
3.1
2.9
0
0
0
0
100
0
0
0
0
0
100
0
0
0
35
9
71
67
50
9
5
Disclosures: This work was supported by R01DA021421 (J.V.) from the National
Institute on Drug Abuse (NIDA) and the Fogarty International Center at NIH.
Dr. Vasilev has ownership interests in the Bulgarian Addiction Institute.
Cognitive Impulsivity
• ♀ < ♂ decision-making & risk-taking
• All ♀ drug user classes à Impaired on IGT
• ♀ Polysubstance Users decision-making:
Risky under ambiguity (IGT)
Risk-averse decision- when contingencies
are explicit (CGT), ≈ ♀ controls
Motor Impulsivity
• ♀> ♂ impulsivity & inattention
• ♀< ♂ discriminability (d’ )
• ♀ Heroin Users à reduced vigilance
• ♀ Amphetamine Users à superior vigilance
Easy
No-Go
Hard
No-Go
Copyright © 2016 Jasmin Vassileva,
[email protected]
Findings support previous findings of sex differences in
neurocognitive impulsivity and suggest that residual
impulsivity related to history of drug addiction is more
pronounced in women, including among drug users in
protracted abstinence. Results also suggest that some
neurocognitive dimensions of impulsivity may differ as a
function of drug class, which argues against a unitary
account of drug addiction.