Research in Medicine

Background: Hypothyroidism and associated mental disorders are prevalent in iodine deficient regions. Since the prevalence of hypothyroidism is unknown in mentally retarded  patients in Iran the present study was carried out over 2003 patients hospitalized in Tehran

 institutes.

 Materials and methods: Following the physical examination and filling the questionnaire,  blood samples were obtained for measuring T₄, T₃, and TSH. Radioimmunoassay technique was used for this purpose.

 Results: Among 2003 candidates, 295(17%) had goiter of grade lb, whereas grade II and grade III goiter were reported in 136(6.7%) and 16(0.8%) of the cases, respectively. T₄ level  was reported as below: 4.1- 4.5 ug/dl in 1.5%, 3.1- 4 in 1.7%, 2.1- 3 in 0.6%, and below 2.1u.g/dl in 0.1% of the mentally retarded patients. 53(2.65%) had TSH level of more than  5mU/l, where most of them (2.15%) had TSH level of 5-10 mU/1. TSH>10mU/l was recorded  in 10 cases. 3 patients were received levothyroxine due to previously diagnosed  hypothyroidism. 76(3.8%) cases were found to have mongolism, where 7(7.9%) of them had hypothyroidism.

 Conclusion: Results have revealed the relatively high prevalence of hypothyroidism in mentally retarded patients. Controlling iodine deficiency disorders as well as screening hypothyroidism seems to be necessary for eliminating mental disorders.