Prenatal and early postnatal exposure to a natural disaster and Attention-Deficit/Hyperactivity Disorder symptoms in Indian children.

The aim of this study was to assess the relation between early exposure to stressful events and symptoms of the Attention-Deficit/Hyperactivity Disorder (ADHD) in children, based on the outcomes from a natural experiment. It was hypothesized that children pre- and postnatally exposed to cyclone Aila have increased ADHD symptoms compared to the control group, and the effect depends on the timing of the exposure. Indian children (8-11 years) prenatally (N = 336) and early postnatally (N = 216) exposed to cyclone Aila were compared to a non-exposed control peer group (N = 285). ADHD symptoms were assessed using the Conner's Teacher Rating Scale Revised. The main effect of exposure to the cyclone on the total ADHD symptoms' score, ADHD index, Hyperactivity and Oppositional symptoms was significant and independent to covariates: age and sex of children, gestational age and birth weight, maternal stress during the year before the study and the socioeconomic status of a family. The timing of exposure and sex of the children were found to be a significant moderator of the relation between early exposure to the natural disaster and ADHD symptoms. The prenatal, but also early postnatal exposure to stressful experiences such as a natural disaster, may disturb the development of cognitive functions and behavioural control, thus increasing the risk of ADHD in children.