Association between prolactin serum levels and cognitive function in chronic schizophrenia patients

Introduction. Several studies have explored the relationship between serum prolactin levels, symptomatology, and cognitive dysfunction in individuals at high risk for psychosis and patients with a first psychotic episode. However, the relationship between such variables is poorly understood in the case of chronic patients. Objective. To assess the relationship between prolactin levels, neuropsychological impairment, and symptom severity in patients with chronic schizophrenia. Method. A total of 31 patients with diagnosis of schizophrenia were evaluated between May and December 2018. The age range was 18 to 60 years, with patients receiving antipsychotic treatment during a month at least. Data was obtained from clinical records, interviews, clinimetry, and with the application of the PANSS and the MCCB battery. For the prolactin measurement, the analysis was performed on a sample of 500 microliters of serum, with a chemiluminescence technique. Results. The sample was comprised mostly by men (77.4%), with a mean age of 37.65 years, 13.29 years of formal education, and disease duration of 11.58 years. No correlations were observed between prolactin levels and PANSS components and subscales. Only in male patients is there a negative correlation was found between prolactin levels with the overall combined score of the MCCB battery and cognitive domains of reasoning and verbal learning. Discussion and conclusions. Men diagnosed with schizophrenia may be particularly vulnerable to the negative effects of hyperprolactinemia on cognition. These preliminary data have clinical implications for close monitoring of prolactin and cognitive decline in males with schizophrenia. Theoretically, these data are suggestive of a protective effect of hormones in women with this condition.