Mechanisms of Action of Medicines for Schizophrenia and Bipolar Illness: Status and Limitations

This paper is not a comprehensive review of the literature. Rather, it is a viewpoint based upon advances in other fields of medicine and genetics that may provide a model for guiding research in psychiatry. The paper discusses the major limitations of the medicines currently used to treat schizophrenia and bipolar illness. The limitations in our understanding of the molecular causes of these two illnesses and our lack of a clear mechanism of action for many of the medicines used to treat them continue to confound the field and impede progress towards finding novel treatments. Until the genetic bases of bipolar illness and schizophrenia are unambiguously identified, progress towards improved diagnosis and treatment will be retarded. An approach to identifying risk genes based upon association studies starting with very large sample sizes based upon currently available diagnoses of bipolar disorder and schizophrenia is advocated.