They are able to. General practitioners are able to write prescriptions for antidepressants but in my experience, g.P.'s are not always aware of the nuances of side effects, interactions with other meds, different kinds of antidepressants, detailed educational information for you and family. Do they have access to a psychiatrist for consultation? If they have experience with these meds and the condition, fine.
GP & Antidepressants. Some do, at least for short while until the patient can get appointment to see a Psychiatrist.