The co-occurrence within one’s lifetime of a psychiatric disorder and a substance use disorder. Comorbidity is the preferred term.
The occurrence of both mental illness and alcohol or drug dependence in the same person. Some authorities estimate that as many as one of every two people with serious mental health problems is also dependent on drugs or alcohol and qualifies as having dual diagnosis. Alcohol is the most commonly used drug, followed by marijuana, cocaine, and prescription medications such as tranquilizers and sleeping aids. Dual diagnosis increases the risk of violence, particularly within the family, and of suicide.
The presence of mental illness in a patient with a history of concurrent substance abuse.