ASSOCIATION OF THYROID FUNCTION WITH POSTTRAUMATIC STRESS DISORDER: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: To conduct a systematic review and meta-analysis describing the association of thyroid function with posttraumatic stress disorder (PTSD) in adults. Methods: The authors conducted a comprehensive search from databases’ inception to July 20, 2018. The meta-analysis included studies that reported mean values and standard deviation (SD) of thyroid hormone levels (thyroid-stimulating hormone [TSH], free thyroxine [FT4], free triiodothyronine [FT3], total T4 [TT4], and total T3 [TT3]) in patients with PTSD compared with controls. Five reviewers worked independently, in duplicate, to determine study inclusion, extract data, and assess risk of bias. The mean value and SD of the thyroid function tests were used to calculate the mean difference for each variable. Random-effects models for meta-analyses were applied. Results: The meta-analysis included 10 observational studies at low-to-moderate risk of bias. Studies included 674 adults (373 PTSD, 301 controls). The meta-analytic estimates showed higher levels of FT3 (+0.28 pg/mL; P = .001) and TT3 (+18.90 ng/dL; P = .005) in patients with PTSD compared to controls. There were no differences in TSH, FT4, or TT4 levels between groups. In the subgroup analysis, patients with combat-related PTSD still had higher FT3 (+0.36 pg/mL; P = .0004) and higher TT3 (+31.62 ng/dL; P<.00001) compared with controls. Conversely, patients with non–combat-related PTSD did not have differences in FT3 or TT3 levels compared with controls. Conclusion: There is scarce evidence regarding the association of thyroid disorders with PTSD. These findings add to the growing literature suggesting that thyroid function changes may be associated with PTSD. Abbreviations: DSM = Diagnostic and Statistical Manual of Mental Disorders; FT3 = free triiodothyronine; FT4 = free thyroxine; MD = mean difference; PTSD = posttraumatic stress disorder; TBG = thyroxine-binding globulin; TSH = thyroid-stimulating hormone; TT3 = total triiodothyronine; TT4 = total thyroxine