Early cannabis use in the context of developmental brain disorders: a particular focus on schizophrenia and autism spectrum disorder

Cannabis use has significant effects on mental health, particularly in relation to conditions like schizophrenia and autism spectrum disorder (ASD), but the relationships are complex. Adolescence is a period of developmental maturation where the brain is particularly vulnerable. Cannabis use during this critical period has been associated with increased risk of schizophrenia and increased risk of psychotic relapse. Importantly, in addition to inducing behavioural changes relevant to the positive, negative and cognitive symptoms of schizophrenia, chronic cannabis use causes numerous changes in the brain associated with the development of schizophrenia, including alterations to the endocannabinoid system (eCBS), neurotransmitter systems and dendritic spine morphology. Considering this, it is an interesting development that the therapeutic use of cannabis, particularly cannabidiol-rich strains, has received increasing attention in the context of ASD therapy. The eCBS plays a crucial role in modulating several disease-relevant behavioural processes, including emotion, mood, sociability and anxiety. Further, alterations in the eCBS, most notably impaired endocannabinoid signalling and cannabinoid receptor activation, are present in individuals with ASD. Studies indicate that the use of cannabis and its derivatives in early life may alleviate key symptoms of ASD. However, the long-term effects of such treatments have not been considered in great detail.