Cannabidiol (CBD) as a novel treatment in the early phases of psychosis

In this review, we consider CBD’s potential as a treatment in the clinical high risk and first-episode stages of psychosis.

Recent functional neuroimaging studies have found differences in brain activation in the hippocampus, striatum, insula and midbrain between CHR individuals and healthy controls. A single dose (600 mg) of CBD attenuated these neural differences in CHR subjects but did not significantly alter symptom levels or have adverse effects (Bhattacharyya et al. 2018b; Wilson et al. 2019; Davies et al. 2020). One week of CBD (600 mg) treatment in the same CHR sample was not associated with significant effects on the symptomatic or cortisol response to an experimental stressor and had no adverse effects (Appiah-Kusi et al. 2020). The results of 3 weeks of treatment in this sample are currently in preparation, and the preliminary data indicate that this longer period of treatment is associated with significant symptomatic as well as neuroimaging effects (Bhattacharyya et al. 2018a; Bossong et al. 2019).

In addition to the amelioration of attenuated psychotic symptoms, a primary aim of intervention in the CHR phase is to reduce the risk of later progression to a psychotic disorder. Assessing whether CBD can influence the risk of transition to psychosis is likely to require treatment over a relatively long duration, as the period of maximal risk is over the first 2 years following clinical presentation (Fusar-Poli et al. 2020). A further consideration is that because only 20% of CHR individuals will develop psychosis in 2 years, a trial of CBD as a preventive treatment would require a sample large enough to yield a transition subgroup of sufficient size to detect an effect on this outcome (Fusar-Poli et al. 2020). Recruitment of sufficiently large CHR samples requires large-scale multi-centre trials, and two such trials have recently started. If it was shown to be effective, CBD would be an excellent candidate treatment for a preventive intervention, as it has a particularly benign side effect profile (Chesney et al. 2020b), a critical requirement for clinical treatment in CHR subjects (McGorry et al. 2009; Morrison et al. 2019) especially if this is over a long period.


I still think 600mg is way too much for me. I would like to try it though, if it was pharmaceutical grade.

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CBD will probably never become a mainstream sz treatment. One, who can patent it? No one? So no money in it. Second, if it does work, the doses required are way beyond what the average schizophrenic’s finances will permit.


GW Pharma patented a treatment for epilepsy made of CBD. It is called Epidolex. Colgate patented a toothpaste with CBD in it.

GW Pharma’s treatment is actually FDA approved and likely to be covered by health insurance (for epilepsy). Colgate’s is OTC.

If it’s promising enough, one of the medical CBD pharma companies will invest the money in trials to get it approved, but right now it just seems to be hospitals, universities and research groups looking at it. One way it might happen is a researcher gets a grant to study clinical high risk people in a placebo controlled trial of CBD for a period of 2 years with more years of follow up (as discussed in the paper.) If that were successful, a pharmaceutical company would probably be willing to take the next steps to run more trials to get it approved. Otherwise, it would be like fish oil - while prescription preparations are available, mostly it is an over the counter supplement you’re responsible for buying on your own. And in that case, yes, impossible to afford at the dosages required.

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