Classification in psychiatry: Does it deliver in schizophrenia and depression?

In the context of ongoing work to develop the next iteration of psychiatric classification systems, we briefly review the performance of current systems against their own stated objectives, for two major diagnostic groupings. In the major groupings of schizophrenia and depression, experience over the last 50 years has highlighted particular inadequacies in the utility and validity of available classifications. Advances in psychiatric knowledge and practice notwithstanding, present classification systems would be enhanced by the incorporation of dimensional components. Minor tinkering with current systems will reflect only a missed opportunity. Improving classification will facilitate quality improvement of mental health systems.