Prolactin concentrations increased in antipsychotic-naïve schizophrenia patients
MedWire News: Prolactin concentrations are increased in antipsychotic-naïve patients with schizophrenia compared with mentally healthy individuals, research shows.
"Patients with schizophrenia have shown hyperprolactinemia secondary to the use of antipsychotics, which block dopamine D2 receptors," explain Brian Kirkpatrick (Texas A&M University College of Medicine and Scott & White Healthcare, Temple, USA) and colleagues.
To investigate whether prolactin concentrations are also elevated in antipsychotic-naïve patients, the researchers studied 33 patients (13 women and 20 men) with nonaffective psychosis and 32 age-, gender-, body mass index-, smoking-, and socioeconomic status-matched mentally healthy controls.
They also investigated whether potentially increased prolactin concentrations among the psychosis patients could be attributed to increased concentrations of thyrotropin-releasing hormone (TRH), ghrelin, or cortisol.
Blood samples collected from the participants revealed that women and men with psychosis had significantly higher prolactin concentrations than gender-matched controls, at 37.1 and 15.3 ng/mL versus 13.5 and 7.6 ng/mL, respectively.
However, there were no significant differences between psychosis patients and controls regarding levels of TRH, ghrelin, or cortisol.
"Our findings suggest that hyperprolactinemia is not due to stress associated with the onset of psychosis, as cortisol levels were similar in both groups, but due to a pre-existing vulnerability," comment Kirkpatrick and team.
"Nor does the increase appear to be due to the effects of TSH or ghrelin, which also impact prolactin release."
Although the mechanism of this increase in prolactin remains unclear, they suggest that prolactin-releasing peptide might account for some of these findings, as its disturbances lead to metabolic disorders similar to those found in first-episode psychosis.
Another possible reason for this increase could be inflammation, which has been reported in antipsychotic-naïve patients with schizophrenia and increases prolactin concentrations, they add.
As hyperprolactinemia is associated with several adverse clinical effects, such as galactorrhea, amenorrhea, menstrual irregularities, erectile dysfunction, and an increased risk of osteoporosis, "better understanding of the causes of this problem, and clinical management when it appears, would help patients with schizophrenia," Kirkpatrick et al conclude.
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By Mark Cowen