ABSTRACT
Mental disorder takes many forms. Mental disorder presents a formidable definitional problem because it is not a type of behavior as such; instead, it is an array of presumed mental conditions, each of which manifests itself in particular and more or less identifiable behaviors, thought patterns, and verbal utterances. Positivism—in the study of deviance, adopting the natural-science approach—is closely related to the approach that philosophers call essentialism. Essentialists are positivists, and so, they are interested in, and study, the epidemiology and the etiology of mental disorder. Psychological and sociological theories emphasize that mental disorders are caused by the patient’s experiences, not exclusively or mainly by an inherent or inner neurological or chemical condition. The American Psychiatric Association regards the two main types of mental disorders as thought and mood disorders.
