How are mental health disorders defined?

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is a guide published by the American Psychiatric Association that explains the signs and symptoms of several hundred mental health conditions, including anxiety, depression, eating disorders, post-traumatic stress disorder and schizophrenia.

The DSM provides criteria for making a diagnosis based on the nature, duration and impact of signs and symptoms. It also describes the typical course of the disorder, risk factors and common co-existing conditions.

Another commonly used diagnostic guideline is the International Classification of Diseases (ICD) from the World Health Organization.

Health insurance companies use the diagnostic coding system of the DSM and ICD in determining coverage and benefits and to reimburse mental health professionals.