The aim of this study was to evaluate the relationship between plasma levels of prolactin and negative symptoms.

One hundred fourteen patients with schizophrenia participated in this cross-sectional study. The patients were assigned to groups with hyperprolactinemia and without hyperprolactinemia. Plasma levels of prolactin and clinical features were compared in these groups.

Negative symptom scores in the group with hyperprolactinemia were significantly higher than the non-hyperprolactinemic group. There was also a positive correlation between plasma levels of prolactin and negative symptom scores. Additionally there was no statistically significant difference between schizophrenia subtypes in terms of prolactin plasma levels. The patients treated with conventionel neuroleptics or novel antipsychotics such as risperidone, paliperidone and amisulpride, had higher prolactin levels than the other patients treated with aripiprazol, olanzapine, quetiapine, ziprasidone and clozapine.

This study indicated that we should be aware of prolactin levels especially when negative symptoms are prominent in patients with schizophrenia. Plasma levels of prolactin could be an important biological marker for the severity of negative symptoms in the treatment of patients with schizophrenia. Thus, this finding may change the present pharmacotherapy for negative symptoms in schizophrenia based on prolactin levels.