Well, as someone who has some bipolar and schizophrenic tendencies, I can say that for myself, and I think generally for people in those categories, based on individuals I've spoken with, the effects tend to be homeopathic, i.e., they tend to be contra-effects. So cannabis sends me into a spiral that would look to many like an LSD or angel dust trip, but can also manifest like speed or any other amphetamine, depending on my mood at the time. I've found when I start off in a good mood, it has more of the amphetamine effect. When I'm in a more contemplative or moody place, I find it sends me on one of those hallucinogenic/paranoid trips. Needless to say, I avoid cannabis entirely for that reason - I don't like the feeling it gives me at all. In the past, it would sometimes make me tired and I'd fall asleep, but more recently, I've been involved in more creative work, and for whatever reason (maybe different receptor reaction in the more-active part of my brain?) cannabis hits me with those bad trips. Also, the study that came out of the UK earlier this year separated cannabinoid from THC to see the effects, and THC was the compound that caused the "speedy" effects in people with bipolarity or schizophrenia (and psychosis too, I believe). An interesting note, which I read but cannot verify, so it could be completely false, is that THC vaporizes at about 180 degrees F, and cannabinoid at 220-225 degrees F. Many people with vaporizers will set the temperature around 200 degrees F, which maximizes THC. It also eliminates the countering effects that cannabinoid has on THC (CBD is considered an anti-psychotic), thus being the absolute worst thing for someone with a MI to ingest.
As to your other question, I've done a pretty solid range of uppers in my life, and generally speaking, the same homeopathic tendency is there. Uppers tend to even me out and bring the highs in a bit closer and less manic. Others I've talked to have had similar experiences. Now, realize this is relative to a level of mania that's not present in the general population per se, so my being evened out and "chill" personality may be higher than your tweaked to the rafters I can't believe I did that I'm flying self. But I can say with certainty that typically they make me far less anxious or manic. There are exceptions, of course, but those could be outliers caused by other substances or due to the pharmacology of the upper itself (we're not talking tested by the FDA here).
Oh, and one last thing. I tend to think cannabis accentuates whatever is already present, rather than being the causal factor, at least short term. I think long term it could be a contributing factor in changing blood chemistry and reactions.
