Erin here – the short answer is no, the research in this area is not yet strong enough to be conclusive. But you could say that about a lot of mental health/psychiatric research!

I actually had an email convo with Dr. Rebecca Haines-Saah about this not long ago

Rebecca is a Health Sociologist working in public health research, with particular expertise in public health and harm reduction approaches to substance use. (As an interesting aside, she was also a teen TV star in the Canadian TV series Degrassi Junior High).

When I asked her about cannabis use in youth with BD, she pointed me to Canada’s Lower Risk Cannabis Use Guidelines, which can be found here: canada.ca/content/dam/phac-aspc/documents/services/publications/drugs-health-products/cannabis-10-ways-reduce-risks/lrcug-eng.pdf and camh.ca/en/health-info/guides-and-publications/lrcug-for-youth

I learnt from her that past versions the guidelines have stated that’s best to avoid cannabis if you have a risk for, or family history of mental illness. This new version is updated to be specific to psychosis, chiefly. This is because this is one area where there is general consensus that there is a clear and robust relationship between use and onset. But she also noted that fierce debate continues about the direction and nature of this relationship (i.e. correlation or causal, chicken or egg). Specific to BD she to pointed me to this high-level review evidence from the National Academies of Sciences, Engineering, and Medicine review:

short excerpt and full book

So, I’d say the jury is still (mostly) out. Clinically, I know people with BD who smoke pot regularly and are doing just fine, and I’ve worked with other people for whom it’s pure poison.

Regarding psychedelics and BD – I’m not aware of any studies (expect perhaps for a few case reports) that have looked specifically at BD and psychedelic use, as a treatment or otherwise. This is hugely interesting area of research though, and one that might/should see real traction in coming years – watch this space. I’ll open this question out to the CREST.BD team and see if there are additional comments on this point…

Erin here. I’m going to lean on the expertise of Dr. Rebecca Haines-Saah here, who’s one of the people I respect the most working in the Canadian cannabis/mental health/public health arena. She has said to me previously “Specific to bipolar disorders I would look at this high-level review evidence from the NAM review”

Previously the guidelines have stated that it is best to avoid cannabis if you have a risk for, or family history of mental illness. This new version is updated to be specific to psychosis, chiefly. This is because this is one area where there is general consensus that there is a clear and robust relationship between use and onset – but there is however much fierce debate about the direction and nature of this relationship (i.e. correlation or causal).

This is a fast-moving and controversial area of research and public health policy though – I’ll be interested to hear whether other members of our CREST.BD team have insights to offer. I’ll also drop Rebecca a message to see if she wants to weigh in further on this question.

Erin again. Dr. Haines-Saah weighed in further by email noting that:

“Specific to bipolar, there is some evidence to suggest that heavy cannabis use puts people at greater risk for suicide. But again, not causal or a trigger of the illness as the person asks. I have had this question from patients with BD interested in medical use for other reasons, so I always advise to consult with their MD because it would be something to watch closely in terms of mood”

She’s referring I believe to this study (note again: weak data currently): https://www.ncbi.nlm.nih.gov/pubmed/31121199

Victoria here – Great question! I live with bipolar disorder, anxiety and psychosis. I can’t cite exact studies – I’ll let my colleagues do that. But from what I know smoking pot can make you more vulnerable to bipolar disorder if you have a family history of it. My opinion is that it’s not worth the risk – especially if you have a history of psychosis.

For myself – I don’t and can’t smoke it. The few times I did, I went into mild to moderate psychoses. It is something I know increases the chances of triggering a mood swing or psychosis for me. I stay away from it.