im currently reading a very interesting book about the brain, it is a marvelous piece of software indeed.
More interesting is that it is a tool that you can change and use, to choose how you experience life.
For example, when youve made your brains believe you are a failure, it will trigger emotions that will cause you think 'i cant do this, i knew this would happen etc.'.
However when these emotions occur but you think 'oh i didnt do it correctly, i can do it, tomorrow ill do it again but right this time', you brain will start to connect the fitting emotions to the thoughts, so when you keep on doing this, and you fail at at something again, instead of feelings of dispare or hopelesness, it will make you have feelings of willpower and determination, followed by healthy thoughts that make you keep on going to do it right and make things better.
No brain is the same, we create our own by living and experiencing while connecting thoughts and feelings to it, and no damage is irreversible (although a gunshot to the brain wouldnt be too good

) because the brain will find new ways around or through it to make things work again.
So therefore we all need different meds when we need them, some dont even need them with enough willpower and positive thinking.
on topic, ive been on mirtazapine (only works as a sleeping aid for me, no anti depressant), wellbutrin (made me violent) and prozac (no effect what so ever) and now i am on effexor 225 for GAD and suicidal depressions.
Works like a charm, no side effects apart from headaches from time to time.