No association between affective and behavioral dysregulation and parameters of thyroid function in youths.

Abstract Objective Evidence from adults suggests that changes in thyroid function are associated with the development of bipolar disorder (BD) and severe mood dysregulation. A dysregulation profile based on the Child Behavior Checklist (CBCL-DP) describes a phenotype with severe mood problems in youth. The present study investigated whether altered thyroid functioning in youths is associated with the severe mood dysregulation symptoms characterized by the CBCL-DP. Methods We analyzed the thyroid function data from 262 children and adolescents (n = 262 for serum TSH, n = 148 for free triiodothyronine [fT3] and n = 153 for free thyroxine [fT4]) with their CBCL-DP composite score. We created and compared high CBCL-DP and low CBCL-DP subgroups with regard to their serum TSH, fT3 and fT4 concentrations as well as the presence or absence of subclinical hypothyroidism. Results We did not detect between-group differences in serum TSH, fT3 and fT4 concentrations, nor were there significant correlations between youths' CBCL-DP scores and their serum TSH, fT3 and fT4 concentrations for either the whole sample or any subgroup. Post-hoc power analyses indicated that adequate to moderate power existed to detect between-group differences in fT3 and fT4 concentrations, respectively, but that larger TSH samples would be required to detect the same differences in those concentrations. Limitations This study had a retrospective design, fewer females than males, and reduced power with respect to TSH concentrations. Conclusions The present investigation does not support the association between elevated serum-TSH concentrations and severe mood dysregulation in youths. However, these findings should be confirmed in future large-scale studies.