glad you brought up the DSM because I have some words for that pile of trash too

DSM is not scientific. That's correct. Diagnostic and Statistical Manual of Mental Disorders or DSM for short, is literally about as scientific as a religious text.

Here's what's going on:
people often use the terms mental illness, mental disorder, and mental disease interchangeably. This is bad, because they all mean different things.

Mental illness: social construction that focuses on society
Mental disorder: social construction that focuses on the individual
Mental disease: a physical problem in the brain. The only scientific phrase out of the three.

An example of a disease of the mind: Alzheimer's!
An example of a mental illness: Depression
An example of a mental disorder: Pedophilia

The amount of people brain-washed by the American Psychiatric Association (APA) just makes me want to build a space-ship and move to another planet :/

If you don't know what a social construction is, it's like an opinion but is applied to society.

So if I decided that a certain behavior needed to be kept under control in my society and that doing so would benefit my society as a whole, I would tell everyone that anyone engaging in this behavior is mentally ill. In this case, being mentally ill means you are a danger to my idea of a perfect society. It's ALL about society, you should really take a sociology class in a university if you like to learn more about this.