[Conduct disorders in seven-year-old children--results of ELSPAC study. 2. Risk factors]

Conduct disorders related to hyperactivity and significant attention deficit are caused by several types of risk factors-genetic, biological, environmental and psychosocial. A cohort of children was followed longitudinally in a prospective study during the pregnancy and childhood (ELSPAC). In the age of 7 years, marked behavioural divergences were described in 4,4% of children by their attending physicians. These children were also more often afflicted by other pathological symptoms (hyperactivity, sleep and psychomotor disorders). From the data collected from parents and physicians in the previous phases of investigation we selected possible risk factors which affect the prenatal and postnatal periods: prenatal exposure of children to smoking, alcohol, chemical substances, prenatal development complications, the level of education of parents, family dysfunction, alcoholism of both parents, conflicts with the police, mother's disturbed mental health.

In the sample of 3752 children from the city of Brno, no behavioural divergence was found in 96.5% of cases. The presence of one or two of the four observed divergences occurred in 3.2% and 3 to 4 conduct disorder symptoms occurred in 0.3% children, significantly more often in boys. The children with conduct disorders compared to the children with no symptoms had significantly lower average birthweight, lower head circumference, their mothers had more often lower education, smoked and had psychological problems in childhood and as adults and the fathers had more often conflicts with the law.

The ELSPAC study did not have the methodological possibility of studying the genetic-environmental interactions; nevertheless it contributes to the evidence supporting that some factors can negatively effect the foetal development and the unfavourable family environment can participate in the development of conduct disorders which can progress during lifetime.