Does depression causes permanent changes in personality of a person?
For example, someone who had depression for a while, after he/she fully recovered from depression, will he/she become totally another person? Changes in personality, thoughts etc.

Is it possible that making someone happy for a long time be a natural treatment for depression?

I did have some health issues a year ago, and ever since then, I have been thinking a lot about my health, and anything that can affect it. So even the smallest things can make me feel worried. Even now I'm worrying about few things regarding health. And it so happens that the things that make me worried are things that I cannot control or change. Imagine how that feels?

At least if it's something u can do, like if a girl reject you, just don't care about it. But this involves HEALTH, LIFE. It's not easy to just say, oh, it's ok. Nothing would happen. Because it can happen.

Maybe it's because I'm the kind of person that only think alot about myself? So u can say, oh, don't care so much about  what happen to urself, get a girlfriend, then u won't bother so much about ur health anymore. Well that's not easy because my motivation in life comes from within myself.

You guys should read this book --> How to Stop Worrying and Start Living by Dale Carnegie