Sex differences in prolactin levels in emerging psychosis: Indication for enhanced stress reactivity in women

Background: Hyperprolactinemia is a known side effect of antipsychotics. In recent reports it has also been shown in antipsychotic-naive at-risk mental state (ARMS) and first-episode psychosis (FEP) patients. Prolactin is not only involved in reproduction and lactation, but is also synthesized in response to stress. As stress is thought to play an important role in the onset and relapse of schizophrenia, the aim of this study was to further elucidate the influence of prolactin in emerging psychosis. Methods: The data analysed in this study were collected within the prospective Fruherkennung von Psychosen (FePsy) study. Blood sample collection took place under standardized conditions between 8 and 10 am after an overnight fast and 30 minutes of rest. All patients were antipsychotic-naive and did not take any prolactin influencing medication. Results: Our sample consisted of 116 antipsychotic-naive ARMS and 49 FEP patients. Hyperprolactinemia was shown in 32% of ARMS and 35% of FEP patients. After correction for the normal biological variation between the sexes, we still found higher average prolactin levels in female than in male patients (beta = 0.42; t = 2.47; p = 0.01) but no difference in prolactin levels between ARMS and FEP patients (beta = -0.05; t = -0.30; p = 0.76). The survival analysis revealed no significant predictive value for prolactin levels to predict transition to psychosis. Conclusion: Our findings support a possible role of prolactin in emerging psychosis and it could be speculated that stress, which can induce hyperprolactinemia, has a stronger effect on women than on men in emerging psychosis. (C) 2017 Elsevier B.V. All rights reserved.