Is (poly-) substance use associated with impaired inhibitory control? A mega-analysis controlling for confounders

Area of Science:

• Cognitive Neuroscience
• Psychopharmacology
• Addiction Research

Background:

• Previous research often linked heavy substance use to impaired response inhibition.
• Studies commonly focused on single substances and dichotomized user groups (heavy vs. light/non-users).
• Polysubstance use and a continuum of use are prevalent but often overlooked.

Purpose of the Study:

• To investigate the association between substance use patterns and response inhibition using a large-scale mega-analysis.
• To address limitations of prior research by considering polysubstance use and a continuum of use.
• To examine demographic and task-specific factors influencing response inhibition.

Main Methods:

• Aggregated individual data from 43 studies comprising 3610 adult participants.
• Utilized Go/No-Go (GNG) and Stop-signal tasks (SST) to assess response inhibition.
• Employed linear mixed-effects models to analyze main and interaction effects of substance use, demographics, and task characteristics.

Main Results:

• Contrary to expectations, only lifetime cannabis use was significantly associated with impaired response inhibition on the SST.
• An interaction effect revealed that the association between tobacco use and inhibition differed between cannabis users and non-users.
• Participant age, education level, and specific task characteristics also demonstrated significant influences on inhibition outcomes.

Conclusions:

• Found limited evidence for widespread impaired response inhibition among recreational substance users when controlling for covariates.
• Highlights the specific role of lifetime cannabis use in response inhibition deficits.
• Suggests that the interplay between different substances (e.g., tobacco and cannabis) and individual differences warrants further investigation.