If you ever get the chance to read or watch the story of Susannah Cahalan I would highly recommend it. It gives an interesting insight into psychiatric diagnoses. Although the story is not about mental illness it certainly covers the lack of knowledge and how quick doctors are to prescribe pills.
When I was first diagnosed they tried many different pills on me – I felt more like a Guinea pig than a patient, and my body rejected most of them. Human chemistry is a fascinating thing. What works for one person can fatally harm another. Thus the reason for so many different drugs out there for doctors to test on us. Surely if something is not working then change it – but remember that no one knows your body better than you do.