Substance related disorders are associated with impaired valuation of delayed gratification and feedback processing: A multilevel meta-analysis and meta-regression.

Across numerous studies, individuals with substance use disorders (SUDs) differed from non-using controls regarding valuation of delayed gratification and feedback processing. However, it remains unclear whether the magnitude of the effect sizes is different across these two cognitive processes and how specific SUDs as well as demographic and clinical moderators influence these effects. In this study we thus performed multilevel linear mixed-effects meta-analyses and meta-regressions to examine the effects of SUDs on the Delay Discounting Task (DD) and on the Iowa Gambling Task (IGT). We found a moderate to large effect for SUD on both, the IGT and DD. While the effect on the DD was generalized to all substance classes, a smaller effect for cannabis-related disorder when compared to other SUDs was found with regard to the IGT. Early onset of substance use and psychiatric comorbidities were associated with stronger effects on the DD. Our findings suggest that feedback processing is more vulnerable to specific substance effects, while valuation of delayed gratification depends more on developmental and clinical factors.

Executive functions rehabilitation for schizophrenia: a critical systematic review.

BACKGROUND: Consistent evidences suggest that poor functional outcomes in schizophrenia are associated with deficits in executive functions (EF). As result cognitive training, remediation and/or rehabilitation (CR) programs have been developed and many theories, methods and approaches have emerged in support of them. This article presents a systematic review of randomized controlled trials (RCT), including EF rehabilitation interventions, with a focus on methodological issues and evidences of EF improvements. METHOD: Electronic databases (Medline, Web of Science, PsycINFO and Embase) were searched for articles on schizophrenia, EF and cognitive rehabilitation terms. The methodological quality of each article was measured by 5-point JADAD scale. RESULTS: A total of 184 articles were initially identified, but after exclusion criteria, 30 RCT remained in this review. A proportion of 23% of studies scored higher than 4 points in JADAD scale, 40% scored 3 points, 33% scored 2 points and one study scored only 1 point. The average length of interventions was approximately 80 h distributed around 3.42 h/week. CONCLUSION: The reviewed articles corroborate the literature pointing that CR could be a promising therapeutic option for cognitive deficits in schizophrenia. In general, CR could improve cognitive domains and social adjustment either using computerized or paper-and-pencil programs. Additionally, CR combined with cognitive behavioral therapy and/or group sessions is particularly effective. In this paper, we also speculated and discussed optimal doses of treatment and the differences regarding modalities and approaches.