Patients and comparison subjects did not differ significantly in distributions of age, sex, handedness or total intracranial volume (p’s > 0.05), but as expected patients had significantly less education (t=−3.94; p=<0.001). Total intracranial volume was 1347 cm3 (SD = 160) in patients and 1353 cm3 (SD = 110) in healthy volunteers. Mean pituitary volumes for patients at the baseline and followup timepoints was 819 mm3 (SD = 137) and 832 mm3 (SD = 137), respectively. Mean pituitary volumes at the baseline and followup timepoints for healthy volunteers was 814 mm3 (SD = 186) and 835 mm3 (SD = 173), respectively.
Neither the main effect of group nor the group-by-time interaction were statistically significant. Similar findings were observed for both the subgroup of antipsychotic drug-naïve patients and a subgroup of patients who took only atypical antipsychotics between scans. There was no significant correlation between antipsychotic drug exposure (in chlorpromazine equivalents) and change in pituitary volume between the two scan timepoints across the entire cohort, in the subgroup of antipsychotic drug-naïve patients, or in the subgroup of patients who took only atypical antipsychotics. A main effect of sex (F=7.08, df = 1,109, p = 0.009) indicated that females had larger pituitary volumes overall compared to males with post-hoc analyses indicating this effect was evident at both the baseline (F=5.43, df=1,109, p = 0.02) and followup (F = 5.92, df = 1,67, p = 0.02) timepoints. shows the baseline pituitary volumes for males and females separately.
Baseline pituitary volumes in males and females