Hi Ramesh,

You are not the first person to ask this question. I've responded to a very similar question before and this was my answer:

My understanding of the action of prozac is that you can't habituate to it. By that I mean if you remain on it for a period of time the effects do not subside and you should not need additional doses to get the effect you did previously. Of course some of the side effects of prozac can in themselves be distressing! The action of prozac on serotonin means your depression should not worsen, but it may mean that you are currently on a dosage that isn't having the therapeutic effect that it should. You may fall into the 'treatment resistive' category, but it may simply mean that an adjustment in your treatment regime is required.

As a psychologist I think it would be remiss of me to ask whether you are relying soley on medication for your treatment of depression? If this is the case I'm not entirely surprised that your thinking patterns haven't really changed. Some very good results have been achieved via cognitive therapy and I think this might be seriously worth considering.