Cannabidiol, or CBD, is one of the most well-known components of marijuana and is not psychoactive like its THC counterpart. It has been touted as a treatment for almost any mental health condition you can think of, but the overall evidence for this in humans is pretty scant. Beyond that, the evidence we do have suggests that effects are isolated to doses far higher than that seen in commercial products.
A systematic review and meta-analysis published towards the end of 2019 was only able to find a small handful of studies examining the effects of pharmaceutical grade CBD on mental health, and the majority of the evidence was rated as low quality. The authors were unable to find any RCTs on the effect of CBD on depression, ADHD, Tourette syndrome, or PTSD. They did include two studies on CBD and anxiety, finding no reduction of symptoms in individuals with an anxiety disorder.
In the realm of mental health, the bulk of CBD work has been conducted in relation to anxiety, and there is a small – but not robust – amount of evidence in favor of an effect.