Increased pituitary volume in antipsychotic-free and antipsychotic-treated patients of the Æsop First-Onset Psychosis Study

ABSTRACT

Subjects at their first psychotic episode show an enlarged volume of the pituitary gland, but whether this is due to hypothalamic–pituitary–adrenal (HPA) axis hyperactivity, or to stimulation of the prolactin-secreting cells by antipsychotic treatment, is unclear. We measured pituitary volume, using 1.5-mm, coronal, 1.5 T, high-resolution MRI images, in 78 patients at the first psychotic episode and 78age- and gender-matched healthy controls. In all, 18 patients were antipsychotic-free (12 of these were antipsychotic-naý¨ve), 26 werereceiving atypical antipsychotics, and 33 were receiving typical antipsychotics. As hypothesized, patients had a larger pituitary volume than controls (+22percent , p=0.001). When divided by antipsychotic treatment, and compared to controls, the pituitary volume was 15 percent larger in antipsychotic-free patients (p¼0.028), 17 percent larger in patients receiving atypicals (p¼0.01), and 30 percent larger in patients receiving typicals (p=0.001). Patients receiving typicals not only had the largest pituitary volume compared to controls but also showed a trend for a larger pituitary volume compared to the other patients grouped together (11 percent, p¼0.08). When divided by diagnosis, and compared to controls, the pituitary volume was 24 percent larger in patients with schizophrenia/schizophreniform disorder (n¼40, p=0.001), 19 percent larger in depressed patients (n¼13, p¼0.022), 16 percent larger in bipolar patients (n¼16, p¼0.037), and 12 percent larger in those with other psychoses (n¼9, p¼0.2). In conclusion, the first-episode of a psychotic disorder is associated with a larger pituitary independently of the presenceof antipsychotic treatment, and this could be due to activation of the HPA axis. Typical antipsychotics exert an additional enlarging effecton pituitary volume, likely to be related to activation of prolactin-secreting cells...