Can you get prescribed antidepressants on your first phsyciatrist visit?

Yes, if your symptom. Suggests the need for one. Psychiatrists are trained to make a diagnosis in the first evaluation.
Antidepressants. Depends on diagnosis and urgency based on severity of symptoms. We normally order blood work in first visit to make sure patients are healthy, and start low dose of medicine to assure tolerability. Antidepressants take while to work.