With the help of psychologists, the next version of the International Classification of Diseases will have a more behavioral perspective. The following mental health professionals can provide psychological assessments and therapy; however, cannot generally prescribe medications (although. The classification of mental disorders, also known as psychiatric nosology or psychiatric . the American Psychiatric Association and it characterizes mental disorder as "a clinically significant behavioral or psychological syndrome or pattern Definitions · ICD · DSM-IV · Other schemes. Learn more from WebMD about the different types of mental illness. Diagnosis and classification of mental disorders and alcohol- and drug-related problems: a research agenda for the s. Psychological medicine. This study examined psychologists ' views and practices regarding diagnostic classification systems for mental and behavioral disorders so as.