Increased self-reported impulsivity in methamphetamine users maintaining drug abstinence

ABSTRACT

Background: Impulsivity has been proposed as an important factor in the initiation and maintenance of addiction. Indirect evidence suggests that some methamphetamine users report less impulsivity when they are using methamphetamine compared to when abstaining from drug use, but this hypothesis has not been directly tested. Objectives/Methods: In this study, self-reports of impulsivity were obtained from 32 methamphetamine-dependent (DSM-IV) research participants and 41 healthy control subjects, using the Barratt Impulsiveness Scale-11. The methamphetamine users were assessed during an active period of methamphetamine use, as determined through urinalysis, and again after approximately 1 week of confirmed abstinence. Control subjects likewise completed two assessments. A subset of participants also completed serial assessments of the Beck Depression Inventory (Methamphetamine Group, N = 17, Control Group, N = 38) and the Methamphetamine Withdrawal Questionnaire (Methamphetamine Group, N = 12). Results: There was a significant interaction of group with time on impulsivity (p = 0.044), reflecting a significant increase from the first to the second assessment in the methamphetamine users (p = 0.013), but no change among healthy control subjects. In contrast, depressive and withdrawal symptoms significantly decreased between the first and second assessments in the methamphetamine users (ps ≤0.01). Change in impulsivity in methamphetamine users was not significantly correlated with change in withdrawal or depression (ps >0.05). Conclusions: These findings suggest that methamphetamine users report more impulsivity when abstaining from drug use, an effect that is not significantly related to methamphetamine withdrawal. Attenuation of impulsivity may reinforce continued methamphetamine use in these individuals.

KEYWORDS:

• Drug abuse
• impulsivity
• methamphetamine
• withdrawal
• self-medication
• abstinence
• stimulant

Funding

The research was funded in part by NIH grants P20 DA022539, R01 DA020726 (EDL), K23DA027734 (ACD), R21DA034928 (ACD), UL1TR000124 (UCLA CTSI), and endowments from the Thomas P. and Katherine P. Pike Chair in Addiction Studies, and the Marjorie Greene Trust. None of the sponsors were involved with the design, collection, analysis or interpretation of data, writing the manuscript, or the decision to submit the manuscript for publications.

Declaration of interest

The investigators have no conflicts of interest or financial disclosures to report.

Additional information

Funding

The research was funded in part by NIH grants P20 DA022539, R01 DA020726 (EDL), K23DA027734 (ACD), R21DA034928 (ACD), UL1TR000124 (UCLA CTSI), and endowments from the Thomas P. and Katherine P. Pike Chair in Addiction Studies, and the Marjorie Greene Trust. None of the sponsors were involved with the design, collection, analysis or interpretation of data, writing the manuscript, or the decision to submit the manuscript for publications.