Physical disorder, as a medical term, is poorly defined, and typically used in contrast to a mental disorder or a genetic disorder. The term mental disorder is heavily used in psychiatric medicine, and is defined in some psychiatric medicine texts, most notably the Diagnostic and Statistical Manual of Mental Disorders (DSM). However, the more generic term of medical disorder is poorly defined, and is not mentioned in the World Health Organization's International Classification of Diseases, nor many common medical textbooks. Attempts have been made to adopt a more universal definition, but there is no widely agreed upon definition.