Association of Thyroid Function with Suicidal Behavior: A Systematic Review and Meta-Analysis

Abstract

Thyroid disease is a very common condition that influences the entire human body, including cognitive function and mental health. As a result, thyroid disease has been associated with multiple neuropsychiatric conditions. However, the relationship between thyroid dysfunction and suicide is still controversial. We conducted a systematic review and meta-analysis to describe the association of thyroid function with suicidal behavior in adults. We searched four data bases (MEDLINE, EMBASE, PsycINFO, and Scopus) from their inception to 20 July 2018. Studies that reported mean values and standard deviation (SD) of thyroid hormone levels [Thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), and total triiodothyronine (TT3)] in patients with suicidal behavior compared with controls were included in this meta-analysis. The abstracts and papers retrieved with our search strategies were reviewed independently and in duplicate by four reviewers for assessment of inclusion criteria and data extraction, as well as for evaluation of risk of bias. Random-effects models were used in this meta-analysis to establish the mean difference on thyroid function tests between groups. Overall, 2278 articles were identified, and 13 studies met the inclusion criteria. These studies involved 2807 participants, including 826 participants identified with suicidal behavior. We found that patients with suicide behavior had lower levels of FT3 (−0.20 pg/mL; p = 0.02) and TT4 (−0.23 µg/dL; p = 0.045) compared to controls. We found no differences in either TSH, FT4, or TT3 levels among groups. With our search strategy, we did not identify studies with a comparison of overt/subclinical thyroid disease prevalence between patients with and without suicide behavior. The studies included in this meta-analysis had a low-to-moderate risk of bias. In the available literature, the evidence regarding the association of thyroid disorders and suicidal behavior is limited. We found that patients with suicidal behavior have significantly lower mean FT3 and TT4 levels when compared to patients without suicidal behavior. The clinical implications and pathophysiologic mechanisms of these differences remain unknown and further research is needed.

Suicide attempt rate and the risk factors in young, first-episode and drug-naïve Chinese Han patients with major depressive disorder

“…People with thyroid diseases are more likely to have depressive symptoms, and depression can be accompanied by subtle thyroid abnormalities [31]. Moreover, a recent systematic review and metaanalysis demonstrated patients with suicidal behavior had significantly lower mean FT3 and TT4 levels when compared to patients without suicidal behavior [32]. Compared with patients without suicide attempts, we found patients with suicide attempts had higher levels of TSH, TgAb and TPOAb, which was in agreement with some previous studies.…”

“…Previously, the occurrence of suicide was associated with autoimmune diseases, including thyroid-specific diseases [32]. According to previous studies, suicide may be more closely associated with autoimmune hypothyroidism rather than autoimmune hyperthyroidism [32]. Patients with a history of suicide attempts showed reduced basal FT4 levels and FT4/FT3 ratio [33].…”

“…A large number of studies have found that dysregulation of immune system is involved in the pathophysiology of not only depression [35][36][37], but also suicide [38][39][40]. Previously, the occurrence of suicide was associated with autoimmune diseases, including thyroid-specific diseases [32]. According to previous studies, suicide may be more closely associated with autoimmune hypothyroidism rather than autoimmune hyperthyroidism [32].…”

Determinants of Diabetic Peripheral Neuropathy and Their Clinical Significance: A Retrospective Cohort Study

“…A meta-study of suicidal tendencies found that 2,807 participants were involved. The study found that patients with suicidal behavior had lower levels of FT3 than patients without suicidal behavior, and the average levels of FT3 and TT4 in patients with suicidal behavior were significantly lower than those without suicidal behavior (54). These studies focus more on the relationship between the reduction of FT3 and disease.…”

Non-Alcoholic Fatty Liver Disease and Hypothyroidism: Review of Clinical and Experimental Studies

“…Thyroid gland diseases are common conditions characterized by a systemic effect on the human body [1]. The number of individuals with hypothyroidism significantly exceeds the prevalence rates of hypothyroidism, which is largely due to geographic dependency and residence in the iodine-deficient areas [2,3].…”