i was on antidepressants for 4 years and it didnt make any real significant change. maybe there was a subtle difference (and certainly the 12th medication i tried helped me feel more energetic), but i cannot say that the medication itself helped my depression lift.

however - onto number 13th (oh gosh) and the depression literally started to lift within 72hrs, and was practically gone within 2 weeks. i have had depressive symptoms since then, but the meds have certainly made my depression easier to manage.

i do agree partly with what vickie says. of course antidepressants have an affect in your brain. the question really boils down to whether depression is caused by those chemicals being impaired in some way. there are massive flaws in the chemical imbalance hypothesis and i for one am very wary of believing the hype.

in terms of lasting change, psychotherapy (CBT and interpersonal therapy, for depression) actually has more of an effect than antidepressants. like echoes, i'm in therapy and i find it incredibly useful in managing my depression. i am still on medication at the moment because i really do need all the help i can get, but my hope is one day to be able to stop them.

i know i've gone on a bit of a ramble . in terms of your question: some antidepressants have a drastic effect for some people, some antidepressants have a mild effect for other people, and there is also a certain subset of people for whom antidepressants can have a clear negative impact (increase in suicidality, or switch to mania if there is an underlying bipolar disorder). i know that is a very vague answer, but it also the most truthful one in terms of what scientists know at the moment.