While your criticism of drug companies funding psychiatric research is valid, there are nonetheless a number of links between “brain chemistry” and mental illness that have been verified by independent researchers. But having established these links, most psychiatrists will prescribe drugs assumed to have the appropriate effect without ever measuring the levels of certain brain chemicals before, during, or after treatment. It is the lack of care, and the misapplication of science, as well as the bias of journals and influence of pharmaceutical companies, that is to blame. I don’t think the notion of adjusting chemical imbalances with drugs to treat mental illness is in itself wrong; though surely it is only grossly effective and not a precision tool like cognitive-behavioural therapy. The real point is the idea has been misused by some psychiatrists, who leap to grand conclusions from a paucity of evidence. That’s not science, that’s for sure – scientists are far more cautious.