Abstract
Social factors significantly influence the initiation and progression of cannabis use and cannabis use disorder. Although cannabis is the most widely used drug globally, its social cognitive aspects and neural correlates have rarely been studied. To evaluate the findings to date and to guide future research, this systematic review assesses neuroimaging evidence on the associations between long-term cannabis use, social cognition, and emotion recognition. Findings from 8 studies on social cognition suggest an increased neural response to social influence and a decreased neural sensitivity to social exclusion, psychosocial stress, and social reward. However, these results should be interpreted with caution, and further replication is necessary due to the limited number of studies in each area. The findings from 21 studies on emotion recognition remain largely inconsistent. Specifically, regarding the amygdala, cingulate cortex, and frontal areas, findings vary, with certain studies reporting increased activity in response to affective stimuli in cannabis users compared to controls, while other studies reported the opposite effect. These effects could be caused by methodological and sample differences across the studies on emotion recognition. Overall, the functional implications, the causal relationship with use, and the role of individual user characteristics, such as the severity of CUD symptoms, gender, and age remain unclear. Future research should involve larger, more diverse samples and specifically target individuals with CUD. Especially, longitudinal studies focusing on social motivational processes, the brain, and the roles of age and gender as potential moderators could provide valuable insights.