Initial clinical trials suggest that CBD is safe, well-tolerated and may have antipsychotic effects in patients with psychosis. There is some indication that CBD may be particularly effective in the early stages of the disorder, such as in patients at clinical high risk and those with first episode psychosis. Neuroimaging research suggests that CBD may exert its therapeutic effects via modulation of brain function in regions known to be altered in patients with psychosis across a variety of cognitive paradigms. Questions remain regarding the full side-effect profile of CBD, with reports of increased liver enzymes and potential for hepatic toxicity, but the most commonly reported side effects (such as diarrhoea and sedation) are likely to be both mild and benign. A more substantial body of evidence, including larger studies with longer-term CBD administration (e.g. up to 2 years), is required to accurately estimate the risk-benefit profile of CBD. Pending such evidence, if CBD treatment were ultimately associated mainly with common sedative and gastrointestinal side effects, these would likely still indicate a favourable tolerability profile compared with the side-effect profiles of currently licensed antipsychotic treatments. Given that CBD has antipsychotic effects without directly acting on dopamine receptors, it could represent a completely novel class of treatment for psychosis. CBD may also have therapeutic value prior to the onset of frank psychosis in patients at clinical high risk for the disorder, and in patients with nonschizophrenia spectrum disorder psychosis, such as Parkinson’s disease.