Cannabis Perturbs Dynamic Brain States

Acute cannabis intoxication alters brain network dynamics, reducing the occurrence of a hyperconnected brain state in both occasional and chronic users. Chronic users show persisting neuroadaptations, including decreased brain network segregation, independent of intoxication. Attentional performance is most impaired in occasional users, suggesting tolerance develops in chronic users. Both acute and persistent effects on brain dynamics correlate with spatial CB1 receptor density. The findings indicate that cannabis-induced cognitive impairment depends on individual neuroadaptations and receptor density, relevant for therapeutic, legal, and societal contexts.

Study at a glance

Abstract

Background The impact of acute cannabis exposure on brain function and cognitive performance varies among individuals. Acute effects of cannabis on behavior may be absent or benign in chronic users, while occasional users experience significant impairment in day-to-day operations. It is hypothesized that repeated cannabis use induces neuroadaptations leading to tolerance and desensitization, although the precise mechanisms underlying these adaptations remain unclear. Methods In this study, we investigated acute and persistent effects of vaporized cannabis on brain dynamics in a placebo-controlled neuroimaging trial involving occasional ( n = 23) and chronic ( n = 20) cannabis users. Functional resting-state data were collected to assess dynamic functional connectivity changes during intoxication and their association with attentional performance and normative cannabinoid CB 1 receptor density. Results Cannabis intoxication induced significant acute alterations in the dynamics of brain network organization, as shown by a reduced occurrence of a hyperconnected brain state in both user groups. Chronic users also displayed decreased segregation of brain networks independent of treatment condition, suggesting persisting neuroadaptations. Dynamic reconfiguration of hyperconnected brain motifs correlated with attentional performance, which was most impaired in occasional users, indicating tolerance in chronic users. Both the acute and persistent effects of cannabis on dynamic brain state organization were significantly associated with spatial CB 1 receptor density. Conclusions Acute cannabis-induced cognitive impairment is influenced by (persistent) network reconfigurations and CB 1 receptor density. These findings emphasize the relevance of neural dynamics and individual neuroadaptations to (prolonged) cannabis use when assessing the behavioral effects of cannabis in therapeutic, legal, and societal settings.