With selective serotonin reuptake inhibitors, which most anti depressants are, it can sometimes take a couple of months of use before the positive effects of it are noticed. It can also take that long for your body to adjust to them and the various side effects like headaches, tiredness, dry mouth, etc. in many people go away. If after 60 days or so on one of these you still don't feel the positive effects, or the side effects are getting in the way of the rest of your life, do not hesitate to ask your doctor to try a different one on you. While all the same family of drugs (SSRI's) each one behaves a little differently in different people. I could not tolerate Paxil, it dried my already dry mouth too much, I moved to a different one and found the same positive results without the dry mouth. Other people swear by Paxil