amphetamines do the exact opposite to antipsychotics. They may provide short-term relief through the initial euphoria, but the mechanism of action for amphetamine is literally flooding the brain with dopamine. That is the opposite of what you want for psychosis.
The schizophrenia thing completely went over my head when I first replied to OP. You have been spot on with your replies though. Treating Schizophrenia with methamphetamine can best be compared to trying to put out a fire with gasoline. Meth alone can cause symptoms of paranoia, hallucinations, emotional instability, and psychosis. Researchers have referenced Schizophrenia in several documents on Meth Psychosis, and the reason is because patients suffering from psychosis exhibited many similar behaviors and symptoms as those suffering from schizophrenia.Hang on... meth to treat schizophrenia? Well that's certainly a new one to me.
Personally I find regular pharma amphetamines (Adderall, Vyvanse, Dexedrine, etc) are effective for depression alone and although I am scripted them for ADHD I told my psychiatrist they're helpful for my depression as well so I have them instead of an antidepressant to unofficially treat depression. Not 100% effective by any means but at therapeutic doses it does work very well with far fewer side effects than nasty SSRIs or TCAs.I had looked at over 15 or so articles and couldn't find any data good enough to post on here to strengthen this hypothesis OP. Many of the studies I read mentioned that it helped with the depression and other negative thought loops in the short-term, but ultimately the consensus is that it is not advisable due to what others have already mentioned. And there are way better ways to treat the negative symptoms of schizophrenia than any amphetamines. Hell, there are better ways to treat regular depression than to use meth. This is a very complex disorder and playing with stims is asking for trouble, in the long term at least. You never know when the flip to positive symptoms will occur.