OBJECTIVES: This study consisting of two subprojects was undertaken to evaluate the effects of hyperprolactinemia on cardiovascular disease (CVD) risk parameters such as anthropometric measures, insulin sensitivity and blood lipids in patients with schizophrenia or related psychoses on long term treatment with antipsychotics.
METHODS: In subproject Ι, 45 patients receiving the 2nd generation antipsychotics risperidone, clozapine or olanzapine were compared regarding prolactin (PRL), body mass index (BMI), insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and blood lipids. In subproject Π, 24 patients receiving 1st or 2nd generation antipsychotics were investigated with diurnal profile of PRL and oral glucose tolerance test (OGTT).
RESULTS: Elevated PRL levels were found in about 45% of the patients and occurred more often in patients receiving risperidone or haloperidol, compared to patients receiving clozapine or olanzapine. In contrast, in subproject Ι, insulin and HOMA-IR were higher and high density lipoprotein cholesterol was lower in patients receiving clozapine or olanzapine, compared with patients receiving risperidone. However, PRL levels did not correlate to BMI, insulin, HOMA-IR or lipids in any of these three treatment groups. In subproject Π, OGTT showed impaired glucose tolerance in 25% and new-onset diabetes in 4% of the 24 patients investigated. Additionally, the PRL (median 24 h) levels correlated positively to the 2 h glucose level at OGTT (rs=0.42, p=0.04).
CONCLUSIONS: Our findings point to that hyperprolactinemia due to 1st and 2nd generation antipsychotics may decrease insulin sensitivity, whereas other mechanisms probably underlie insulin resistance induced by PRL-sparing antipsychotics such as clozapine and olanzapine.