How is a mental health disorder diagnosed?
Mental disorders can only be diagnosed by a medical doctor or a psychiatrist. In order for a diagnosis to be made, certain criteria in the Diagnostic Statistics Manual (DSM http://allpsych.com/disorders/dsm.html) must be met. For example, to be diagnosed with depression, symptoms must be either severe or long-lasting, and it must not be due to a specific life event. The purpose of the DSM is to keep diagnoses similar between different doctors.
