Increased serum prolactin levels in drug-naive first-episode male patients with schizophrenia

Background: Prolactin is a hormone receiving considerable attention in psychiatry. Increased serum prolactin level is frequently associated with dopamine blocking antipsychotics. Furthermore, decreased prolactin level was considered a reflector of the effect of antipsychotics. However, there is restricted numbers of investigations that researched baseline prolactin levels in first-episode patients with schizophrenia. Aims: We purpose to investigate serum baseline prolactin levels in drug-naive first-episode patients with schizophrenia (FES) and to explore the differences in serum prolactin levels between FES, drug-free schizophrenic patients (DFS) and healthy controls (HC). Material and Methods: The study was conducted in the Departments of Psychiatry, Golbasi Hasvak and Kirklareli State Hospitals, Turkey. Thirty male FES, 41 male DFS and 32 male HC were included in study. All participants were clinically examined and individually interviewed. Before initiating any pharmacological treatment, 5 ml of venous blood was collected to measure serum prolactin levels between 08:00 and 10:00 h, which was determined by radioimmunoassay (RIA). Prolactin levels were also collected from the consenting HC using the same assay. Results: The mean age was higher in the DFS group. The mean score of Brief Psychiatric Rating Scale was higher in the FES group and mean score of Scale for the Assessment of Negative Symptoms was higher in the DFS group. The mean value of prolactin was higher in the FES group (34.1 +/- 19.9 ng/dl) compared with DFS (17.9 +/- 6.5 ng/dl) and HC (9.7 +/- 2.3 ng/dl) (F = 35.5, P < 0.001). Additionally, the mean value of serum prolactin is higher in the DFS group compared with HC (P < 0.001). Conclusion: To our knowledge, this study is the first to demonstrate higher serum prolactin levels in male FES compared with male DFS and male HC. Prolactin might act as a protective factor while first episode of schizophrenia is experienced. Future studies are needed to provide the role of prolactin in schizophrenia.