What is mental disorder?

The question of definition of mental disorder and the related question of its boundaries have been, and remain, of crucial importance in many contexts. Two approaches were evident from the beginnings of modern psychiatry approximately 100 years ago: the medical and the psychological models, differing in several critical respects, particularly on whether or not psychiatric conditions are meaningful and understandable, and the related question of whether or not the abnormal is clearly differentiated from the normal. A third approach, the sociological, emphasized the strong connexion between so-called mental disorder and social deviance, and appeared forcefully in the 1960s as critiques of mainstream psychiatry. These controversial issues remain alive, sharpened by major changes since the 1960s, particularly the development of medications for common mental health problems and the development of care in the community for severe mental health problems.