Are Schizophrenia and Bipolar Disorder Completely Different Conditions?

Kraepelin initially proposed distinguishing schizophrenia and bipolar disorder by their course and phenomenology, but he later questioned this dichotomy. Today, some scientists wonder whether there is a common predisposition to a spectrum of disorders of which psychosis can be a feature. To learn more, these researchers studied families with prominent mood and psychotic symptoms.

The investigators performed genome scans of 35 sibling pairs from 24 British or Irish families; each family had multiple histories of schizophrenia or bipolar disorder and at least one member diagnosed with DSM-IV schizoaffective disorder, bipolar type. Both in bipolar-disorder and in schizophrenia families, barely significant linkage was found to chromosome 1q42; t…