In sum, the acute use of cannabis may offer relief from various symptoms linked to anxiety, stress and depression. However, the long-term consequences of cannabis use seem to have higher potential for harmful outcomes for these conditions. Nevertheless, other confounding factors may play a role in heightening these risks. Indeed, as recently reported [109,164], the World Health Organization (WHO, [3]) and the National Academies of Science, Engineering, and Medicine [165] concluded that the effects of cannabis use on depression seem to be limited and slightly increase the risk of developing depression. Nevertheless, a systematic review [166] that appraised 44 previous systematic reviews, including 1053 different studies covering a broad spectrum of negative health outcomes directly connected to cannabis use, concluded that a clear association exists between cannabis use and psychosis, affective disorders, anxiety, sleep disorders, cognitive failures, respiratory adverse events, cancer, cardiovascular outcomes, and gastrointestinal disorders. Several studies have concluded that cannabis use during adolescence had a strong impact on risk for psychosis and incidence of schizophrenia as well as a causal association with poor school performance, lower educational attainment
