There was a significant reduction in parvalbumin cell density in the pre-frontal cortex regions of patients with schizophrenia relative to healthy controls (Hedges’ g = − 0.27; z = − 2.17; p = 0.03; 95% confidence interval (CI): − 0.51 to − 0.03) (Fig. 2). Here, PVALB is linked to schizophrenia.