[cr33pyguy]

To be clear, being hyper-logical is a sign, and usually also a symptom, of depression. Hyper-logical people do not tend to have normal levels of pleasure, as being hyper-logical is usually a coping mechanism for stress.

@Ichi, I'd say you're sociopathic, which caused depression. From everything you've described, you're either incapable of, or have forced yourself not to, feel certain emotions. In other words, what you've done may actually worsen your depression.

As I've already stated, one cannot easily "control" chronic or severe depression. It has caused a chemical imbalance. At that point, it is no longer a mental issue, it is a biological one, and a person should seek medical help.

I am assuming you're talking of the depressive disorder when you say depression?
But yes, depression is a symptom of depressive (and other) disorders.
And yes, as your last paragraph states, that's why "antidepressants" work. Even though sometimes depression (not severe) is a purely psychological problem... Psychology is complicated and therefore interesting, I appreciate your knowledge of it