Unreality symptoms and volumetric measures of Heschl's gyrus and planum temporal in first-episode psychosis

Background: Schizophrenia may involve dysfunction to primary auditory, speech, and language processes governed by the superior temporal gyrus (STG). These processes are implicated in hallucinations, delusions, and thought disorder. The current study explored the relationship between unreality symptoms (hallucinations and delusions) and specific STG substructures, including Heschl's gyrus (HG) and planum temporale, (PT). Methods. Twenty-five right-handed men within their first episode of psychosis were assessed using the Positive and Negative Syndrome Scale (PANSS) for the presence of hallucinations and delusional behavior (a composite score of delusions, grandiosity, suspiciousness, and unusual thought content). T1-weighted magnetic resonance imaging (MRI) scans were acquired using a 1.5 Tesla scanner. Stereological measurements of HG and PT volume were obtained. Linear regression methods explored the relationship between regional volumes and symptoms. Results: Reductions in left HG were associated with hallucinations and delusions. Increases in left PT were associated with delusional behavior. Conclusions: Current results implicate HG dysfunction in unreality symptoms in men with recent-onset schizophrenia.