Low thyroxine levels in female psychiatric inpatients with riboflavin deficiency: implications for folate-dependent methylation.
Intermediates in the folate-dependent methylation pathways may play a role in the etiology and treatment of such mental disorders as major depression. These pathways include a step dependent on a riboflavin (B2)-derived coenzyme, flavin adenine dinucleotide (FAD), which is reportedly sensitive to thyroid status and to phenothiazine and tricyclic drug exposure. In a sample of 52 male and female acute psychiatric inpatients, 17% (n = 9) showed B2 deficiency (i.e., insufficient FAD activity) on a functional red blood cell enzyme assay, but only one B2-deficient individual showed deficiency in another B-complex vitamin (folate). All patients with B2 deficiency were women, who were also significantly younger than the rest of the sample. The B2-deficient women had significantly lower thyroxine levels, even when controlling for sex and covarying for age. B2-deficient patients exhibited a nonsignificant trend toward more unipolar depression (44% vs 14%), but not toward bipolar or schizophrenic disorders. As in a previous study, drug exposure did not show a relationship to riboflavin deficiency in this sample. The findings suggest that B2 (FAD) activity may serve as a sensitive marker of thyroxine status in certain female psychiatric inpatients and that B2 deficiency may play an etiological role in defects of the methylation pathways in a subset of mentally ill individuals.
Bell
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Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont.
Morrow
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Read
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Berkes
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Perrone
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D000328:Adult; D005260:Female; D005492:Folic Acid / Q000097:blood*; D005494:Folic Acid Deficiency / Q000097:blood / Q000523:psychology; D006760:Hospitalization; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000097:blood* / Q000523:psychology; D008875:Middle Aged; D011736:Pyridoxine / Q000097:blood; D012256:Riboflavin / Q000097:blood; D012257:Riboflavin Deficiency / Q000097:blood*; D012436:S-Adenosylmethionine / Q000097:blood*; D013831:Thiamine / Q000097:blood; D013960:Thyroid Function Tests; D013974:Thyroxine / Q000097:blood*; D014805:Vitamin B 12 / Q000097:blood
D012436:S-Adenosylmethionine; D005492:Folic Acid; D011736:Pyridoxine; D014805:Vitamin B 12; D013974:Thyroxine; D012256:Riboflavin; D013831:Thiamine