Thyroid Status and Serotonin Production in Children with Impaired Growth and Neuropsychological Development

Thyroid hormones (TH) are essential for the development and maturation of the central nervous system. Serotonin, 5-hydroxytryptamine (5-HT), is an important chemical and neurotransmitter in the human body. It appears to play a key role in neural activities and social behaviors. The effects of TH and serotonin during development of CNS appear similar. Transient hypothyroidism is common in children with impaired CNS maturation. The levels of serotonin production in these children remain unclear.

Objective: To evaluate serotonin levels and thyroid status in children with impaired growth and neuropsychological development.

Materials and Methods: Target group: 118 children 0–3 years old from orphanage.

Methods: physical, psychomotor development assessment; thyroid status by TSH, TT4, TT3 serum-based measuring (IMA); peripheral blood serotonin measurement («IBL Hamburg», Germany).

Results: All children were accepted in to an orphanage at the age 2.5-3.5 months. They had impaired physical development (44.9%), delayed psychomotor development (95.7%), decreased coefficient of neuropsychological development (82 points). TSH level median was 3.21mU/l [QR: 3.1; 3.8]. Negative linear correlation by PPMCC between TSH levels and coefficients of neuropsychological development was detected (ρ=−0.436, p=0.001). In children with minimal thyroid dysfunction median serotonin level was 204.1nmol/ml [QR: 202.1; 206.1], vs in children with optimal thyroid function 185.1 nmol/ml [QR: 177.7; 189.7], р

Conclusions: In young children, disorders of physical and neuropsychological development are associated with transient hypothyroxinemia and hyperthyrotropinemia. Unlike adults, hyperthyrotropinemia is associated with increased serotonin production. Perhaps such increase in serotonin production is an additional mechanism aimed at completing the maturation of the nervous system.