Dual diagnosis (mental illness and substance abuse)
The term dual diagnosis denotes a condition where substance dependence, or other excessive substance use, co-occurs with at least one mental health disorder that is not a direct effect of the substance use (intoxication and withdrawal symptoms).Substance abuse (alcohol, legal and illegal drugs and solvents) may affect a patient’s mental illness in different ways. It may precipitate mental illness worsen mental illness alleviate mental illness have no effect on mental illness. The relationship between the patient’s different mental health disorders and substance abuse is not necessarily always the same. In dual diagnosis, mental illness will persist even when substance use has ceased for a prolonged length of time.