The aim of this study was to evaluate the relationship between plasma levels of testosterone, FSH, LH and prolactin and the severity of negative symptoms in patients with chronic schizophrenia. Fifty-four male inpatients with chronic schizophrenia participated in this cross-sectional study. Twenty-five age-matched men without a history of psychiatric disorders or endocrine illnesses were used as controls. All patients were on risperidone 4 mg/day or haloperidol 10 mg/day and anticholinegic medication, biperidine 3 mg/day. The patients were assigned to groups with predominant negative and nonpredominant negative symptoms on the basis of their scores on the Positive and Negative Syndrome Scale (PANSS). Plasma levels of testosterone and free testosterone in the patients with predominant and nonpredominant negative symptoms were significantly lower than those in normal controls. Furthermore, plasma levels of FSH and LH, in the patients with predominant negative symptoms but not in the nonpredominant negative symptoms, were significantly lower than those in the normal controls. In contrast, plasma level of prolactin in the predominant negative symptoms group but not in the nonpredominant negative symptoms group was significantly higher than the aged matched normal males. Significant inverse correlation between negative subscale scores of PANSS and plasma levels of testosterone and free testosterone in the patients with predominant negative symptoms were detected. There was also a positive correlation between prolactin plasma levels and negative subscale scores. The present study indicates that assessment of sex hormones and function of hypothalamic-pituitary-gonadotropin axis could be an important biological marker for the severity of negative symptoms in schizophrenia and these findings may change the present pharmacotherapy for negative symptoms based on neuroendocrinology profiles of patients with schizophrenia.
