Dual diagnosis is an important part of co-morbidity.
The term Co-Morbidity is preferred since Dual Diagnosis has been mainly applied to psychiatric illnesses with substance use disorders, as well as developmental disability with concurrent mental health disorders. There is a lack of integration between mental health and alcohol and other drug services. Putting it very simply, clients with co-morbidity of mental disorder and substance use,usually have to visit different services to access treatment for their substance use and mental illness. The increasing recognition of this issue means that the prevalence of this problem is uncertain. Recent figures have suggested that as many as three quarters of all clients with alcohol and other drug problems have a dual diagnosis.