['The relationship of bipolar disorder (BD) and altered thyroid function is increasingly recognized. Recently, a behavioral phenotype of co-occurring deviance on the Anxious/Depressed (A/D), Attention Problems (AP), and Aggressive Behavior (AB) syndrome scales has been identified as the Child Behavior Checklist Dysregulation Profile (CBCL-DP), which itself has been linked to BD. This study tested for differences in thyroid function within a sample of n=114 psychiatric children and adolescents with and without the CBCL-DP.', 'A CBCL-DP score was generated based on the composite of the crucial CBCL syndrome scales (A/D, AP, AB). Participants with a CBCL-DP score >or=2.5 SDs above average constituted the CBCL-DP subgroup (n=53). Those with CBCL-DP scores of 1 SD or less above average percentile were regarded as controls (n=61). Groups were compared regarding serum levels of TSH, fT3 and fT4.', 'In participants showing the CBCL-DP, basal serum TSH was elevated compared to controls. More CBCL-DP subjects than controls showed subclinical hypothyroidism. No differences were observed for serum fT3 and fT4 levels.'] Is severe affective and behavioral dysregulation in youth associated with increased serum TSH?