I have been researching this for many years and studied psychotherapy in both London University and Middlesex. I have many papers on here and elsewhere, which examine the subject, I believe, thoroughly.
My conclusion:
A discipline of opinion with a concentration on 'identity'. The drugs, which became a speciality of mine, I consider extremely dangerous; dangers that are ignored by the profession.
Psychiatry gets immense credibility from its connection to medicine (of course), an extremely and excessively powerful institution, but also to the drug companies.