Hi Melissa,
First off. The best person to ask these questions of is your doctor, but there is some common info out there. Everyone metabolizes these meds a bit differently, but usually you should start to see an improvement after a couple weeks. It also depends on what dose you are on. Are you taking the same dose you were when you were feeling well? If not, it may be that the dose is too low (but again, follow drs instructions for dosing).
I know that much of the literature explains that if you have had 1-2 episodes of depression in your life you can often wean off the medications after feeling well fo 6 mos to a year...but this same literature also talks about people who have lifelong chronic depressive episodes and how they may need to be on medication for the rest of their lives to remain.
stable.
From what I understand depressive episodes, if left untreated, or undertreated, take on a kindling effect. With each episode, the likelihood of having another episode increases. Also, each episode may become more severe or last longer than the previous episode. It is a big reason why it is important to treat depression as early as possible.
I know for me I am the perfect example of this kindling effect. I had deppression as a child, but had my first serious depressive episode(DE)at 19. It lasted about 6 mos. Then at 23 I had another(DE)...lasted longer and was much more severe, at 25 had another...lasted longer still, afterwards remained dysthymic for a long while, had a few more DE's, then at 30 or 31 I fell into a severe DE that lasted 2 plus years...throughout all this I took no medication, but I did go into therapy (especially for the 2 yr episode). Had another Severe Episode a year later, had a few months of okay and have now been in the most severe DE I've ever been in for 3.5 years straight. (Really I have been in a DE for 6-7 years because I literally only had a few months between this and the last episode)
Why am I saying all this? To help others not fall into the hell I have fallen into. Get help as early as possible and if you find a medication that works...if your doctor suggests staying on it...stick to it. I still have not found a med that works, but I'm telling you, once I do I will stay on it forever.
...Aqua