mental illness. Avoiding categorical diagnosis Current nosological approach does not provide a framework for internal (sub-threshold symptoms) or external (comorbidity) heterogeneity of the different diagnostic categories. The prevailing "Neo-Kraepelinian" diagnostic system solely accounts for a categorical diagnosis, therefore not allowing for the possibility of dual diagnosis. There has been substantial criticism to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), due to problems of diagnostic overlap, lack of clear boundaries between normality and disease, a failure to take into account findings from novel research and the lack of diagnostic stability over time. History The traditional method for treating patients with dual diagnosis was a parallel treatment program. In this format, patients received mental health services from one clinician while addressing their substance use with a separate clinician. However, researchers found that parallel treatments were ineffective, suggesting a need to integrate the services addressing mental health with those addressing substance use. During the mid-1980s, a number of initiatives began to combine mental health and substance use disorder services in an attempt to meet this need. These programs worked to shift the method of treatment for substance use from a confrontational approach to a supportive one. They also introduced new methods to motivate clients and worked with them to develop long-term goals for their care. Although the studies conducted by these initiatives did not have control groups, their results were promising and became the basis for more rigorous efforts to study and develop models of integrated treatment. References Further reading Addiction psychiatry Alcohol and health Drug rehabilitation Substance dependence Substance-related disorders 2 (number)