Hyperprolactinemia and Antipsychotic Therapy in Patients With Schizophrenia

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A recent study determined hyperprolactinemia (HPRL) was not associated with taking antipsychotic drugs with high expected HPRL risk.¹

HPRL is a side effect of some antidepressants and antipsychotics. HPRL is frequently observed in patients with schizophrenia and can also occur in Hashimoto's thyroiditis due to the prolactoliberin effect of thyroliberin. In women, it may present with decreased libido, infertility, oligomenorrhea/amenorrhea, and galactorrhea; in men, it may present with decreased libido, infertility, gynecomastia, or impotence.²

In the recent study, patients with comorbid schizophrenia and Hashimoto's thyroiditis who received antipsychotics were of special interest, as these patients have higher risks of HPRL. Investigators sought to analyze risks of HPRL with antipsychotic treatment, identify an association between the antipsychotic therapy and HPRL in Hashimoto's patients receiving antipsychotic therapy, and explore the association of HPRL in patients with Hashimoto's thyroiditis and schizophrenia during antipsychotic therapy.

Investigators examined 17 participants with comorbid schizophrenia receiving antipsychotic therapy, all euthyroid or with light hypothyroidism. They analyzed different laboratory parameters, including anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) antibodies, blood levels of thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) and prolactin (PRL).

Results revealed high levels of PRL, and anti-TPO and anti-TG autoantibodies. Patients were then classified into 3 groups by the degree of expected HPRL risk from antipsychotics: without risk, with low risk, and with high risk. The correlation analysis detected an inverse significant correlation (R=-0.51; p=0.037) between expected level of drug-associated HPRL risk and actual PRL levels in the group. At the same time, we detected a positive significant correlation between the levels of PRL and FT4 in the groups (R=0.53; p=0.03). Correlations between PRL levels and other parameters such as TSH, FT3, anti-TPO, anti-TG, anti-TSH receptor antibodies were not statistically significant.

HPRL in the group was not associated with taking of antipsychotic drugs with high expected HPRL risk. Yet, a significant positive correlation existed between the levels of PRL and FT4. Hence, in Hashimoto's thyroiditis accompanied with treated mental illness there are some non-iatrogenic stimulants of prolactogenesis.

“It cannot be ruled out that antipsychotics may interfere with prolactin metabolism, which creates a false effect of a positive correlation between prolactin and free thyroxine levels, in contrast to common HPRL of hypothyroidism,” concluded the authors.¹

References

1. Sobolevskaia PA, Churilov LP, Fedotkina TV, et al. Hyperprolactinemia and antipsychotic therapy in schizophrenic patients with Hashimoto's thyroiditis. Psychiatr Danub. 2021;33(Suppl 4):1106-1112.

2. Luciano AA. Clinical presentation of hyperprolactinemia. J Reprod Med. 1999;44(12 Suppl):1085-1090.