The diagnosis and classification of disorders allows professionals to make important decisions regarding treatment, and promotes communication and research as well as highlighting aspects of etiology. DSM-V, the manual of the American Psychiatrists Association (APA) is a leading diagnostic tool for most disorders. DSM uses a multi-axial approach, where axis I indicates the presence of clinical disorders and mental retardation, axis II personality disorders and mental retardation, axis III current medical conditions, axis IV psychosocial and environmental effects, and axis V the overall level of functioning. Another widely used diagnostic tool is ICD-10 (International Classification of Diseases by the World Health Organization).