[Calcium balance and regulation in schizophrenic patients treated with second generation antipsychotics]

Calcium balance and regulation play an important role in providing its normal plasma concentration. Hormonal regulation is mostly done by parathormone and vitamin D. Impaired balance may result in bone demineralization, decreased bone mineral density and cause osteopenia and osteoporosis. In patients with a diagnosis of schizophrenia it can be due to dietary and vitamin deficiencies, decreased sunshine exposure, as well as polydipsia and other reasons. There is no substantial data exploring the influence of second generation antipsychotics on calcium dynamics in schizophrenic patients.

The aim of the study was to evaluate calcium and phosphate metabolism in patients with a diagnosis of schizophrenia treated with second generation antipsychotics in reference to a control group of healthy, non-medicated volunteers.

Participants in the study were 60 schizophrenic patients: 26 were treated with risperidone, 34 with olanzapine and 38 were healthy, non-medicated volunteers--the control group. Subjects were excluded for any medical condition or treatment known to alter calcium balance. Blood samples for analysis were fasting morning ones. The following parameters were measured: serum levels of ionized calcium and phosphate, serum levels ofparathormone and serum levels of 25-hydroxy-vitamin D3. Also a 24-hour urine sample was collected for the measurement of urinary calcium and phosphate.

There was no significant statistical difference between mean serum calcium and phosphate levels in schizophrenic patients and the control group and between patients treated with risperidone and those treated with olanzapine. 24 hour urine calcium and phosphate concentration was decreased in schizophrenic patients comparing to controls, but there was no difference between groups treated with risperidone or olanzapine.