Hyperprolactinemia and Antipsychotic Therapy in Schizophrenic Patients with Hashimoto's Thyroiditis.

INTRODUCTION: Hyperprolactinemia (HPRL) is known as a side effect of some antidepressants and antipsychotics. These medicines are common in treatment of schizophrenia. Thus, HPRL is often observed in schizophrenic patients. It is also known that HPRL can occur in Hashimoto's thyroiditis due to prolactoliberin effect of thyroliberin. The clinical pathophysiology of the patients with the comorbidity of schizophrenia and Hashimoto's thyroiditis, receiving antipsychotics, is of special interest. It's fair to assume that these patients have higher risks of HPRL. To analyze risks of HPRL with antipsychotic treatment, to identify an association between the antipsychotic therapy (AT) and HPRL in Hashimoto's patients receiving AT, to explore the association of HPRL and other laboratory parameters in patients with Hashimoto's thyroiditis and schizophrenia during AT. SUBJECTS AND METHODS: We studied 17 patients with HT in comorbidity with schizophrenia receiving AT (mean age 46.5±12.8 years), all euthyroid or with light hypothyroidism. Different laboratory parameters such as 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) were analysed. RESULTS: The study revealed the high levels of PRL, anti-TPO and anti-TG autoantibodies. Thus, patients were classified into 3 groups by the degree of expected HPRL risk from the antipsychotics used: without expected risk, with low and high expected risks. 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 studied 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). The correlations between the levels of PRL and other parameters such as TSH, FT3, anti-TPO, anti-TG, anti-TSH receptor antibodies were not statistically significant. CONCLUSIONS: 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.

Thyroid gland and brain: Enigma of Hashimoto's encephalopathy.

The versatile clinical manifestations of the Hashimoto's chronic autoimmune thyroiditis often include psycho-neurological disorders. Although hypothyroidism disturbs significantly the ontogenesis and functions of central nervous system, causing in severe cases of myxedema profound impairment of cognitive abilities and even psychosis, the behavioral, motor and other psychoneurological disorders accompany euthyroid and slightly hypothyroid cases and periods of Hashimoto's disease as well, thus constituting the picture of so called "Hashimoto's encephalopathy". The entity, although discussed and explored for more than 50 years since its initial descriptions, remains an enigma of thyroidology and psychiatry, because its etiology and pathogenesis are obscure. The paper describes the development of current views on the role of thyroid in ontogeny and functions of brain, as well as classical and newest ideas on the etiology and pathogenesis of Hashimot's encephalopathy. The synopsis of the world case reports and research literature on this disorder is added with authors' own results obtained by study of 17 cases of Hashimoto's thyroiditis with schizophrenia-like clinical manifestations. The relation of the disease to adjuvant-like etiological factors is discussed. Three major mechanistic concepts of Hashimoto's encephalopathy are detailed, namely cerebral vasculitis theory, hormone dysregulation theory and concept, explaining the disease via direct action of the autoantibodies against various thyroid (thyroperoxidase, thyroglobulin, and TSH-receptor) and several extrathyroid antigens (alpha-enolase and other enzymes, gangliosides and MOG-protein, onconeuronal antigens) - all of them expressed in the brain. The article demonstrates that all above mentioned concepts intermingle and prone to unification, suggesting the unified scheme of pathogenesis for the Hashimoto's encephalopathy. The clinical manifestations, criteria, forms, course, treatment and prognosis of Hashimoto's encephalopathy and its comorbidity to other diseases - are also discussed in brief. The relation between Hashimoto's encephalopathy and non-vasculitis autoimmune encephalomyelitides of paraneoplastic and non-paraneoplastic origin is emphasized [1 figure, bibliography - 200 references].