I'll try to concisely outline this explanation here, so anyone who reads it can think about it and tell me if, and how, it may be off the mark.
I think of this as a narrative sequence of interactions among a doctor, a patient, possible other people, and facts in a clinical setting.
In most medical practices and specialties it goes this way:
1. A person has some sort of pain, malfunction of the body, or other symptoms.
2. The person takes himself to a doctor and complains, asking for a solution.
3. Doctor listens, inspects the body, does any of various medical tests, verifies presence or absence of objective abnormalities.
4. Doctor evaluates the data and makes a diagnosis.
5. Doctor offers the patient a recommended treatment with full information regarding risks and benefits.
6. Informed patient accepts the treatment or goes elsewhere for another opinion.
7. Patient or third party pays doctor.
In psychiatry, by contrast, it goes like this:
1. A person behaves in ways upsetting to someone else.
2. Someone else who is upset with the person convinces him to go to a psychiatrist, or takes him to one like-it-or-not, and complains about the behavior, asking for a solution.
3. Psychiatrist listens, believes the complaints, briefly interviews the patient.
4. Psychiatrist prescribes treatment which he hopes might restrain the patient's unacceptable behavior about which someone else complains.
5. Psychiatrist looks in the DSM for a diagnosis to justify treatment.
6. Patient is convinced by various devices, or coerced, to accept treatment.
7. Patient or third party pays psychiatrist.
OK. It seems to me the most notable difference is the precisely reversed sequence of steps 4 and 5. (I wrote about this at least once before.) But the only step that is the same for regular medicine and psychiatry is number 7, somebody pays.
You, readers, please tell me what's wrong with this understanding.