Until a properly scientific way to define 'normal' exists, psychiatry will be a largely subjective endeavor that defines "normal" largely on the basis of contingent cultural and sociological factors, and necessarily the "disorders" will reflect this (since the disorders are defined as deviations from normalcy). I think one great example of this is the fact that homosexuality used to be defined as a mental disorder.
Psychiatry is a pretty crazy field of study, if you study the history, it's not hard to work out it's just a new age pseudo-science control tool, since religion is less popular in modern times, the Elites needed a new way to control the masses. Historically, not only was homosexuality considered a psychiatric disorder, so was slaves running away from their owners. The mental illness was called Drapetomania, it caused black slaves to flee captivity (lol). One of the causes was slave owners made “themselves too familiar with [slaves], treating them as equals.(lol)
These days Psychiatry is just as evil, if you look at Oppositional Defiant Disorder for instance, it's parallel with drapetomania is frightening. Symptoms are a pattern of defiant, disobedient, and hostile behaviour toward authority figures that persist for at least six months. It is characterized by the frequent occurrence of at least four of the following behaviours: losing temper, arguing with adults, actively defying or refusing to comply with the requests or rules of adults, deliberately doing things that will annoy other people, blaming others for his or her own mistakes or misbehaviour, being touchy or easily annoyed by others, being angry and resentful, or being spiteful and vindictive.
Children, after all, are in a form of captivity and as they get older may naturally resent having decisions made for them. They may especially dislike being confined most days in stifling government institutions allegedly dedicated to education (“public schools”). Some may rebel, becoming vexatious to the authorities.
It seems that the common denominator of what are called mental (or brain) disorders is behavior that bothers others which those others wish to control. People do not have to be told that malaria and melanoma are diseases. They know they are. But people have to be told, and are told over and over again, that alcoholism and depression are diseases. Why? Because people know that they are not diseases, that mental illnesses are not “like other illnesses,” that mental hospitals are not like other hospitals, that the business of psychiatry is control and coercion, not care or cure. Accordingly, medicalizers engage in a never-ending task of “educating” people that nondiseases are diseases.
No one believes drapetomania is a disease anymore. Slaves had a good reason to run away. We all have reasons–not diseases–for “running away.”