I was recently diagnosed as bipolar, and am a long-time toker. Someone I really trust (in the medical field) who knows this about me cautioned me about smoking herb, and I am taking his advice. I smoke very infrequently now. With everything he told me, I would highly suggest against regular usage. If you are on an anti-psychotic especially - it can interfere with how your meds work. It was tough for me to take this news, since herb helps me with other ailments I have. You just have to do what you have to do to make yourself healthy.
I have bipolar type I and I have been in and out of mental hospitals many, many times. I have seen the bipolar+marijuan=severe mania equation play out very, very frequently over the past ten years. Whenever I was smoking it regularly, as in smoking it every night for a month or more, it would
always end in
severe mania and a trip back to the mental hospital.
I found that I could smoke it a few times a year and I was completely fine. These days, I gave it up just to be extra safe.
I found it to be very therapeutic in the beginning, but I can't smoke it. I know
some people with the disorder who smoke it often and do not suffer any negatives. I also know a
lot of fellow bipolar people who smoke it very often, are obviously hypomanic or manic, but of course they think that their pot smoking is completely fine; they don't realize how sick they are.
If you have to smoke at all, I would keep it as a once in a while treat; a few times a year. Once a month at most. You don't want to needlessly suffer going in and out of hospitals. Just exercise extreme caution.
I have spoken to a lot of psychiatrists/psychologists/therapists, have read a lot of books about bipolar disorder, and the consensus seems to be that marijuana is extremely good at bringing out symptoms of mental illness, making them worse, and triggering mania.
Talk to your treatment team and ask them what they think, then listen to what they have to say. You'll probably hear a lot of what I've said here.
A lot of bipolar people think that they are fine when they are using drugs, but this is because when a bipolar person is manic, he has no insight into his own symptoms; he doesn't realize that he's sick and manic, so obviously he's going to say he's completely fine.
Lastly, I leave you with this: Not everyone who has bipolar disorder has this problem, but you won't know how far you can take it until something bad happens to you (or doesn't).