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Hauser et al., Baltimore, MD, USA, measured corpus callosum size
(CCs), using brain MRI in 56 subjects with resistance to thyroid hormone
(RTH) + ADHD, 43 RTH without ADHD, and 42 control subjects (CS). They found
a significantly smaller CCs in RTH + ADHD as compared to the other two
groups. The results suggest that normal myelinogenesis is impaired in this
group of patients.
Rovet et al., Toronto, Canada, studied attention, activity and behaviour in three groups of 7- 12 year olds: 26 with early treated congenital hypothyroidism (CH), 43 with ADHD and 60 normal controls. In ADHD, FT4 was in 100% below the mean of the reference range while no association was found with corresponding TSH levels. In CH 9% had low T4 while 73% had T4 above the mean of the reference range, while T4 and FT4 were negatively correlated with TSH. In ADHD inattention but not hyperactive symptoms were associated with low T4 levels and in CH only high activity correlated with T4. The authors conclude that in ADHD a mild hypofunction of the hypothalamic-pituitary-thyroid axis may have impact on attentional functioning but not activity, whereas in CH higher T4 levels (most likely due to overtreatment) predict poorer attention and greater activity. They suggest that their findings have implications for treatment of both ADHD and CH. Bhatara et al., Toronto, Canada, describe 4 children with ADHD who's symptoms were aggravated by thyroid hormone treatment. Two boys and 1 girl had CH diagnosed by newborn screening and 1 girl had juvenile hypothyroidism after being diagnosed ADHD. These 4 children developed psychiatric symptoms and the authors suggest the need to involve psychiatrists and psychologists with a special interest in child psychopharmacology for treating typical pediatric thyroid disorders. |
