Acute cognitive and psychiatric effects of cannabinoids

Cannabinoids are known to affect cognitive function and to trigger or worsen psychiatric symptoms and disorders. This review aims at providing a comprehensive outline of the existing literature on the acute effects of cannabinoids on these domains. Recent and relevant evidence shows that cannabinoid intake acutely affects several basal cognitive domains such as learning, memory, and attention. As well, clear acute impairing effects on decision-making, sensitivity to reward, and inhibition are consistently reported, whereas evidence on compromised working memory and problem solving is less solid. Cannabinoid consumption leads to euphoria, relaxation, and increased sociability but can also trigger undesirable effects such as psychotic symptoms/disorders, anxiety and panic, dysphoria, and negative affect in both clinical and non-clinical samples. Δ9‐tetrahydrocannabinol (THC) seems the main culprit for these acute impairments, while evidence supporting potential protective effects of cannabidiol (CBD) is mixed but continues to grow. Dose and THC:CBD ratio, frequency and chronicity of use, pre-existing vulnerability, and demographic/psychosocial factors may moderate these effects. High-potency cannabis (“skunk”) and synthetic cannabinoids (“spice”) have stronger adverse effects and are more dangerous. The existing literature is limited by heterogeneity in terms of populations investigated, compounds and doses administered, and route of administration. More research on high-potency and synthetic compounds, less explored domains, and the role of CBD is needed. This review provides crucial insights on the acute effects of cannabinoids on cognition and mental health that may have important clinical, social, and legal implications.