Introduction: Hyperprolactinaemia is associated with the use of potent dopamine-2 receptor blocking anti-psychotic agents in schizophrenia and with bone loss in the general population. Significantly higher rates of reduced bone mineral density (BMD) have been identified in young pre-menopausal females with schizophrenia receiving prolactin-raising anti-psychotics compared to those receiving prolactin-sparing anti-psychotics. This prospective study compared BMD alterations over a period of 1 year in patients maintained on either prolactin-raising (e.g. risperidone, amisulpride or depot anti-psychotics) or prolactin-sparing (olanzapine) anti-psychotics. The effects of specific interventions to improve BMD were also examined in the context of whether patients were receiving either prolactin-raising or anti-psychotics or Olanzapine.
Methods: Pre-menopausal females (n=38) with a diagnosis of schizophrenia, who had received exclusively either prolactin-raising (n=25) or prolactin-sparing (n=13) anti-psychotics during their treatment history, had clinical, endocrine and bone marker assessments performed at baseline and every 3 months for a period of 1 year. BMD was measured by DEXA scan at baseline and at 1-year follow-up. Patients from both groups either received specific interventions (n=16) or no interventions (n=16) to improve bone density.
Results: There was an overall gain in lumbar BMD values in the prolactin-sparing subgroup, compared to an overall loss in the prolactin-raising subgroup (p=0.02), for the groups that received no specific interventions to improve BMD. Within the group that received specific interventions, the subgroup receiving prolactin-sparing anti-psychotics had a significant increase in lumbar (p=0.01) and hip (p=0.01) BMD over time, whereas alterations in the prolactin-raising subgroup were not significant.
Discussion: Women taking prolactin-raising anti-psychotics and not receiving specific interventions to improve bone density had evidence of ongoing bone demineralisation over a year; whereas women taking prolactin-sparing anti-psychotics had a modest overall increase in BMD. Most clinical interventions appeared to be helpful, but were significantly more effective in those taking prolactin-sparing anti-psychotics.