What are the psychological effects of using synthetic cannabinoids? A systematic review

Synthetic cannabinoids are more potent than natural cannabis because they fully activate the CB1 receptor, potentially causing more serious psychological effects. A review of 17 studies found that acute use impairs cognitive functioning and alters subjective psychological ratings compared to placebo. Non-intoxicated users show lower cognitive performance and elevated symptoms like paranoia compared to natural cannabis users and non-users. Methodological limitations across studies hinder conclusions about how dose, frequency, or type of synthetic cannabinoid influences outcomes. More research is urgently needed as use increases in at-risk populations.

Study at a glance

Abstract

BACKGROUND: Synthetic cannabinoids are, typically, full agonists at the cannabinoid CB1 receptor, and therefore considerably more potent than natural cannabis and may have correspondingly more serious psychological effects. Despite government sanctions against their production they continue to be available in ever-increasing varieties over the Internet. The psychological consequences of synthetic cannabinoid use are relatively unknown. AIM: The purpose of this study was to synthesise the available research on the psychological consequences of synthetic cannabinoid use. METHOD: A literature search of three databases was conducted in February 2018, including the following keywords: Spice, synthetic cannabis, cognition, affect, behaviour, psychosis, depression and anxiety. RESULTS: Seventeen studies involving a variety of participants were eligible for inclusion: one controlled administration study, seven cross-sectional studies, five Internet surveys and four qualitative studies. The controlled administration study showed that, compared to placebo, synthetic cannabinoids acutely affected some aspects of cognitive functioning and subjective psychological ratings. Non-controlled, cross-sectional studies generally showed that synthetic cannabinoid users had lower performance on cognitive tasks and showed elevated symptomatology (e.g. paranoia) compared to both natural cannabis and non-cannabis users. Methodological limitations were noted across different study designs. There is limited research on how doses, frequency or type of synthetic cannabinoid influence outcomes. CONCLUSIONS: Acute synthetic cannabinoid use can result in a range of psychological outcomes and, when non-intoxicated, synthetic cannabinoid users appear to differ from natural cannabis and non-users on various affective and cognitive domains. As synthetic cannabinoid use is increasing in at-risk populations there is an urgent need for more and better research to inform users, professionals and policymakers.