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

Many studies have reported that heavy substance use is associated with impaired response inhibition. Studies typically focused on associations with a single substance, while polysubstance use is common. Further, most studies compared heavy users with light/non-users, though substance use occurs along a continuum. The current mega-analysis accounted for these issues by aggregating individual data from 43 studies (3610 adult participants) that used the Go/No-Go (GNG) or Stop-signal task (SST) to assess inhibition among mostly "recreational" substance users (i.e., the rate of substance use disorders was low). Main and interaction effects of substance use, demographics, and task-characteristics were entered in a linear mixed model. Contrary to many studies and reviews in the field, we found that only lifetime cannabis use was associated with impaired response inhibition in the SST. An interaction effect was also observed: the relationship between tobacco use and response inhibition (in the SST) differed between cannabis users and non-users, with a negative association between tobacco use and inhibition in the cannabis non-users. In addition, participants' age, education level, and some task characteristics influenced inhibition outcomes. Overall, we found limited support for impaired inhibition among substance users when controlling for demographics and task-characteristics.

Identifying Inhibitory Subcomponents Associated with Changes in Binge Drinking Behavior: A 6-Month Longitudinal Design.

BACKGROUND: Links between response inhibition and young adult problematic drinking (e.g., binge drinking) have been established, but only to an extent. Considering the presence of some inconsistent findings associated with these 2 variables, this study proposes the need to investigate the extent in which different inhibitory subcomponents are associated with binge drinking behaviors of the same sample. METHODS: Through the use of a 6-month longitudinal design, changes in Alcohol Use Questionnaire (AUQ) binge score of 163 college students (50.3% female) with a mean age of 21.06 years (SD = 1.83) were correlated with performance on 3 different inhibitory control tasks. Each task was selected to assess separate inhibitory subcomponents: Stop Signal Task (e.g., cancellation of a response), Go/No-Go Task (e.g., withholding of a response), and Simon Task (e.g., inhibiting response interference). Response inhibition was also compared between 2 groups, those who had a substantial increase in AUQ binge score during participation (inAUQ) and those who had a substantial decrease in AUQ binge score (deAUQ). RESULTS: A significant correlation was found with a change in AUQ binge score and stop signal reaction time among females only, where an increase in binge drinking score positively correlated with a reduced ability to cancel an already-initiated inhibitory response. Differences in inhibitory performance, where inAUQ performed worse than deAUQ, approached significance. CONCLUSIONS: The results suggest that the cancellation of a prepotent response, as opposed to the withholding of response or interference inhibition, is a more sensitive inhibitory measure associated with increases in binge drinking behavior among female young adult college students. Further exploration of inhibitory subcomponents relative to substance use is greatly needed (e.g., more extensive longitudinal designs and neuroimaging techniques).

Inhibitory Performance Predicting Drinking Behaviours Among Young Adults.

AIMS: While inhibition has been studied extensively in correlation to alcohol abuse within the adult population, it has been studied less so in relation to the alcohol consumption habits of young adults. Accordingly, this is the first study with the objective of identifying which subcomponent(s) of inhibitory performance, behaviourally measured by the withholding of a pre-potent response, the cancellation of a pre-potent response and interference inhibition will best predict binge drinking habits among young adults. METHODS: Forty-nine collegiate adults (41 females) with a mean age of 21.92 ± 1.34 years, performed three cognitive batteries assessing inhibition: Stop Signal task (SST), Go/No-Go task (GNG) and Simon task. Participants completed two biweekly alcohol logs, 2 and 4 weeks following inhibitory assessment. RESULTS: Regression analysis revealed that interference inhibition (Simon task) and/or withholding inhibition (GNG) contributed to the prediction of total intoxication days and total hangover days. CONCLUSION: These findings suggest that specific subcomponents of response inhibition, and not others, are more suitable for predicting alcohol consumption habits.