Developing Therapeutics for Bipolar Disorder (BPD): From Animal Models to the Clinic

This chapter focuses on the development of therapeutics for Bipolar Disorder (BPD). BPD is a chronic and highly debilitating illness, characterized by periods of normality and periods of illness that are not well controlled by current treatments. It imposes a huge burden on patients, their families, and society as a whole. The unmet need for better treatments is perhaps greater than for any other psychiatric illness. The chapter provides an overview of the DSM-IV-TR diagnostic criteria for BPD and considers the elements that can or should be used as the basis for animal models. Animal models should be less focused on reproducing symptoms of mania or depression and more focused on the underlying mood instability inherent in BPD. An overview of the status of animal models of BPD suggests that there has been a period of inflation here too, but many of the models are still “borrowed” or adapted from other disorders, notably unipolar depression and schizophrenia. This reflects the fact that a large proportion of drugs that are used to treat BPD were first developed for other illnesses. To date, no diagnostic biological markers for BPD have been identified; consequently, the development of new drugs for the treatment of BPD and the parallel development of animal models to test them will remain largely focused on clinical symptoms defined by DSM-IV-TR or ICD-10. These systems of diagnosis are empirical and evidence based, giving rise to a reliable classification of the patients encountered in the physician's office. However, DSM and ICD were not explicitly intended as the basis from which to conduct research.