Prolactin concentrations in newly diagnosed, antipsychotic-naïve patients with nonaffective psychosis.

Background: Previous studies have found increased prolactin concentrations in antipsychotic-naïve patients with schizophrenia. However, the roles of other hormones, and of potentially confounding variables such as gender and smoking, have not been considered.

Methods: Blood from newly diagnosed, antipsychotic-naïve patients with nonaffective psychosis (13 women and 20 men) and matched controls (12 women and 21 men) was assayed for prolactin, as well as three other hormones that impact prolactin concentrations: thyrotropin-stimulating hormone (TSH), ghrelin, and cortisol.

Results: Patients had significantly higher prolactin concentrations: female patients had a mean [SD] of 37.1 ng/mL [24.9] vs. 13.5 ng/mL [7.2] for female control subjects (p=.001), while male patients had a mean of 15.3 ng/mL [9.5] vs. 7.6 ng/mL [2.2] for male control subjects (p=.006). Patients and control subjects did not differ on concentrations of TSH, ghrelin, or cortisol. The group differences could not be attributed to differences in age, gender, smoking, body mass index, ethnicity, or the socioeconomic status of the family of origin.

Conclusions: Increased prolactin concentrations in antipsychotic-naïve patients do not appear to be due to important confounding variables, or to the effects of elevated TSH, ghrelin, or cortisol.