I am about to finish med school and become a phychiatrist. And I have to tell you that you can't write pharmaceutical treatments off. Many people have been saved because of them and I have witnessed it. I can't deny there is arrogance governing the actions of some people in profession but don't dismiss phychiatry like that. The tests that check the behavioural patterns are well studies and they do leave subjectivity mostly out of the equation(every doctor in all specialities still has his unique opinion)
Many biochemical tests are also about to take place in the clinical practice just give it some time. I don't agree with some practices that are taking place but black and white in phychiatric diseases and their treatment does not exist there is just too much grey to know before-hand what is right.