[washadjeffmad]

Sufferers of schizophrenia have also been shown to have a very strong preference for smoking tobacco, so the question still remains unanswered whether people with schizophrenic tendency merely have that similar preference for marijuana, and whether that use might also trigger or exacerbate the pre-existing mechanisms for schizophrenia in their brains.

Someone else mentioned bipolar disorder, and it's interesting to note that schizophrenia, schizoaffective disorders, and bipolar disorders share a similar relationship to dopamine, and so the primary method of action of many anti-psychotic medications is to block dopamine reuptake.

Also interesting is that things like alcohol withdrawal, amphetamines, and marijuana deplete dopamine while tobacco, heroin, and cocaine stimulate its production.

[xkcd-sucks]

do you have a ref for the differential regulation of dopamine synthesis by amphetamine and cocaine?

[washadjeffmad]

I don't, and I see that I implied synthesis when I should have said that they only inhibit its reuptake, except for amphetamine, which also stimulates dopamine release.

Here's a general article on it: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC368179/

Good catch.