With the additional power available from a combined cohort of 45 schizophrenia subjects paired with non-psychiatric comparison subjects, we were able to conduct formal mediation tests demonstrating that lower MAP2-IR mediated reductions in the density of dendritic spines in primary auditory cortex, suggesting that pathology of MAP2 is related, potentially in a causal manner, to pathogenic processes. This evidence concerns the gene MAP2 and schizophrenia.