Originally Posted by
comfyone 
How do psychiatrists know if you need anti-depressants? Do you have to be depressed for an extended amount of time like 6 months to a year? Do you have to not respond to regular therapy for a long time too? Does your depression have to show no apparent root or cause?
Or do they just give you a prescription after three visits and call it a solution?
They are suppose to do a clinical interview (ask you questions to get an idea of symptoms you may be displaying), assess for need, and then go from there. It really depends if you are seeing them for a med referral (most likely you leave with a script), a general consultation (therapy and/or meds), or another reason.
The criteria for getting on a med depends on the doc and your situation. Let the doc know what is going on and they can work with you. I'd guess (obviously YMMV) that if you were showing signs of depression s/he'd probably give you something to see how you do on it for a month or two....as it usually takes a bit to kick in.