How can you be happy?

To answer this overall research question I will try to find out:

1. what makes people happy?
2. what is depression?
3. what medications can you take to "make you happy"?
4. is your happiness in your control?
5. what are emotions? what makes emotions?
6. serotonin? norepinephrine? 

This is what I already know about this topic and what I want to find out:

I know that everyone feels different and has different emotions. People take medicine if they are depressed, and that seems to make the feel better. For example, when someone is diagnosed with clinical depression, they may be prescribed Cymbalta which increase the levels of the neurotransmitters, serotonin and norepinephrine, in the brain, or Celexa which works by increasing just the amount of serotonin in the brain. I know that everyone wants to be happy. I don't know if some people choose to be unhappy or if that is something beyond their control, but I do know that when people are happy, others around them tend to be happy too.