Intellectual development, mental and behavioural disorders in the children whose mothers were exposed to pathogenic radioecological and psychosocial factors as a result of Chernobyl accident at the different stages of pregnancy

The study examined psychological development in 187 children at the age of 6-7 and 10-11, who had suffered prenatal radiation exposure at the time of the Chernobyl accident in 1986. These children were compared to a control group of 150 children of the same age from non-contaminated areas of Belarus. The examination included neurological and psychiatric examination, intellectual assessment and clinical psychological investigation of parents as well as estimation of thyroid exposure in utero. The exposed group manifested a relative increase in psychological impairment compared with the control group, with increased prevalence in cases of specific developmental speech-language disorders (8.56% and 4.67% at 10-11 years old) and emotional disorders (18.2% and 7.3% at 10-11 years old). The mean IQ of the exposed group was lower than that of the control group and there were more cases of borderline IQ (IQ=70-79) (14.4% and 8.0% at 6-7 years; 6.42% and 4.0% at 10-11 years). The mean value of thyroid doses from 131l 0.4 Gy was estimated for children exposed in utero. No correlation was found between individual thyroid doses and IQ at age 6-7 years or 10-11 years. We notice a positive moderate correlation between IQ of children and the educational level of their parents. There was a moderate correlation between high personal anxiety in parents and emotional disorders in children. We conclude that a significant role in the genesis of borderline intellectual functioning, specific developmental disorders of speech, language and scholastic skills as well as emotional disorders in the exposed group of children was played by unfavourable social-psychological and social-cultural factors such as a low educational level of parents, the break of microsocial contacts and adaptational difficulties, which appear following the evacuation and relocation from the contaminated areas.