The Effects of Prolactin-Raising and Prolactin-Sparing Antipsychotics on Prolactin Levels and Bone Mineral Density in Schizophrenic Patients

Introduction: We aimed to investigate the effects of antipsychotics on prolactin levels in patients diagnosed with schizophrenia and the effects of hyperprolactinemia on bone mineral density (BMD) in patients on long-term antipsychotics.

Method: In this study, we included eighty consecutive patients who were diagnosed with schizophrenia according to DSM-IV, had been using the same antipsychotic for the last ten months, and fulfilled the inclusion criteria. Data on sociodemographic characteristics of the patients were collected through an information sheet. The Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS) were used to rate positive and negative symptoms of the patients. In addition, their body mass indices (BMI) were calculated. Prolactin levels were measured through luminescence immune assay and BMD measurements were made at lumbar and femoral sites using dual-energy x-ray absorbtiometry. Haloperidol (n=20) and risperidone (n=20) were assigned to prolactin-raising antipsychotic group, and olanzapine (n=20) and quetiapine (n=20) were assigned to prolactin-sparing antipsychotic group for this study. The effects of antipsychotics on BMD were compared among these groups.

Results: Hyperprolactinemia was determined in 60% of haloperidol using patients, 90% of risperidone using patients, 25% of olanzapine using patients and 10% of quetiapine using patients. Mean prolactin levels were found to be significantly higher in prolactin-raising antipsychotic using group (p<0.001). There were no statistically significant differences in BMD values between the two groups, for the sites where the measurement was done. Lumbar spine and femoral neck T-scores and Z-scores in the prolactin-raising group significantly negatively correlated with the treatment durations and chlorpromazineequivalent doses (p<0.05). BMI and BMD values of both groups also displayed statistically significant positive correlations (p<0.05).

Conclusion: The statistically significant differences in mean prolactin levels and numbers of patients with hyperprolactinemia between the treatment groups support the validity of classifying the antipsychotics as prolactin-raising and prolactin-sparing". The relationship of BMD with the treatment duration and doses in the prolactin-raising antipsychotic using group was deemed to be important, since it indicated that a decrease in BMD was to be expected in long-term antipsychotic treatment.