PVALB and schizophrenia: Data from 28 immunohistochemistry studies (362 control participants, 335 individuals with schizophrenia) revealed that the hippocampus and prefrontal cortex were most consistently characterized by alterations in GABAergic interneurons; parvalbumin and somatostatin interneuron density was reduced in the hippocampus, while data from 18 mRNA studies (524 control participants, 519 individuals with schizophrenia) indicated reduced parvalbumin and somatostatin expression in prefrontal cortex.