Cannabis side effects are generally thought to be mild, but the cannabinoid THC has one very worrying side-effect that is not shared by its cousin, CBD. Recent research seems to confirm that THC can trigger psychosis.
Medscape reports on a study done in the south of London on first-episode psychosis (FEP) patients who continued the use of high potency cannabis.
Lancet Psychiatry and JAMA Psychiatry published two studies done by the same researchers. These studies suggest the time has come to stop wondering about the psychotic effect of high potency cannabis. There are indications that if you’re predisposed to psychosis, high potency weed could push you over the edge – and if you continue to use it after a first episode, your chances of relapse are significantly higher.
These findings are seen as evidence that the key psychoactive, delta-9-tetrahydrocannabiniol (THC), the main psychoactive ingredient in cannabis, is connected to temporary psychotic symptoms, and cognitive dysfunction in healthy people, and worse in patients with previous psychotic disorders.
High on “high” potency
High potency THC cannabis has become very popular, and widespread in the UK. The high potency cannabis has minimal concentration levels of cannabidiol (CBD), which might have antipsychotic properties. The study also showed high frequency, high potency skunk users relapsed earlier than hash using, and low-frequency users. These results support previous evidence of dose-response effectiveness of cannabis in patients with psychosis. It clearly demonstrates that the effects of cannabis used in patients with psychosis depends on the type of cannabis, and the frequency of use.
This might explain why some previous studies, which didn’t differentiate between types of cannabis also didn’t report on the relationship between cannabis use, and relapse of psychosis. The risk of relapse was also higher than the pooled odds of previous studies looking into relapse in the general context.
The fact that there was no difference in the outcome of patients who stopped using cannabis after they experienced psychosis, and those who never used it “suggests the effects of previous use on the outcome in psychosis are not irreversible.”
Dr. Bhattacharyya, study author, said the ideal would be for all psychosis patients to stop using cannabis. Second best would be to reduce frequency, and change to less potent cannabis as an intervention for patients who are unable to stop using cannabis.
The study was praised, but some concerns were raised:
Firstly could patients clearly identify the type of cannabis they were using?
The binary approach might be too simplistic for such a complex plant as cannabis.
The suggested less frequent use of less potent cannabis might be problematic as not all users are the same, and some might simply use more to obtain the familiar high.
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Commenting on the findings for Medscape Medical News
- Levin, MD, Kennedy-Leavy Professor of Psychiatry, Division of Substance Abuse, Columbia University Medical Center, and chair, American Psychiatric Association Counsel on Addictions, said the authors should be more cautious of the factors contributing to their findings.
Who are you working for?
Two of the doctors have not disclosed relevant financial relationships where as one received industry-sponsored grants from Pfizer, and served on a data monitoring committee for Novartis.
CBD side effects?
Dr Bhattacharyya notes there is some suggestion that CBD might have some anxiolytic (anti-psychotic) effects. He states that he and his colleagues have recently tested the theory that CBD reduces anxiety in a placebo-controlled study on patients at high risk of developing “frank psychosis.” It seems the findings have not yet been made public.
However a prediction is possible, since earlier work has concluded that CBD side effects do not include psychosis. On the contrary, the study concluded that CBD could prove to be an effective treatment for psychosis, and particularly schizophrenia. Since CBD is believed to have many similar benefits to THC, this is good news for Cannabis as a medicine, as psychosis is the single side-effect of Cannabis that is most troubling.