It's so much easier to give everyone tranquilizers and SSRIs to even out everyone's heads, than to rearrange the retarded society that's bringing them on in the first place.
"Mental Disorders" or more specifically "Mood Disorders" are bullshit in my opinion. Most things in this little category are fixed by having the subject use analysis of his own consciousness to figure out how his head works. When you know how your head works, it's easier to fix problems.
Of course this doesn't apply to all mental illness, there are plenty of severe forms of psychosis and severe behavioral disorders that do need medication.
Self diagnosed mental disorders (as in people saying they have OCD because they're really organized or energetic people saying that they have ADHD)
are bullshit.
There are three kinds of actual conditions, and the line between them gets blurred all the time.
There are actual personality traits that are similar to symptoms of some disorders, and then there are actual melatonin imbalances and the like, which result in depression, avoidance, anxiety, obsessive compulsive (which is kind of a hybrid between chemical imbalances and brain structure abnormalities), attention deficit and various other disorders. Then there are pervasive developmental disorders, which are on the level of autism, aspergers and such. Those are less chemical imbalances and more actual brain structure abnormalities and are subsequently way harder to deal with and treat.