Schizophrenia and bipolar disorder show both common and distinct changes in cortical interneuron markers

Schizophrenia and bipolar disorder are often viewed as distinct clinical disorders, however there is substantial overlap in their neuropathologies. While compromised cortical interneurons are implicated in both diseases, few studies have examined the relative contribution of the distinct interneuron populations to each psychotic disorder. We report reductions in somatostatin and vasoactive intestinal peptide mRNAs in prefrontal and orbitofrontal cortices in bipolar disorder (n = 31) and schizophrenia (n = 35) compared to controls (n = 34) and increased calbindin mRNA in schizophrenia. We show, at the molecular level, shared deficits in interneuron markers in schizophrenia and bipolar disorder, and a unique interneuron marker increase in schizophrenia.