Getting back to the original question, I think the reason that psychiatry in general has been looked down upon for so long is because relatively little (still) is known about the pathophysiology of the brain, and people have long been suspicious of the way psychiatry was done for so many years.
In the areas of pathophysiology and etiology, psychiatry still lags far behind the rest of medicine, despite advances. For a long time, the field was dominated by individuals such as Freud, and psychoanalysis was the method of choice for many mental health disorders. That, of course, has largely changed - the field now aknowleges that most of the severe illnesses (e.g. schizophrenia, bipolar disorder) substantially involve biological processes, and that issues such as "bad parenting" (for lack of a better term) may play a minimal role in these illnesses.
I find it painful to imagine someone with schizophrenia simply being treated by daily "talk" sessions for years, and being told that his or her illness was the fault of them or their parents. In her biography, Katherine Graham describes how her husband, a world-renowned journalist-publisher, and presidential advisor to JFK, developed bipolar disorder as an adult, and was repeatedly hospitalized until he committed suicide. This was all before the advent of lithium in the US and most other psychotropic medications. Nowadays, not treating those illnesses with meds would be considered malpractice. It doesn't surprise me that people don't always trust psychiatrists.
