Do Lifestyle Factors Influence the Onset of ADHD in Children?

With a worldwide prevalence of 5%, attention deficit hyperactivity disorder (ADHD) is the most common behaviour disorder in childhood

With a worldwide prevalence of 5%, attention deficit hyperactivity disorder (ADHD) is the most common behaviour disorder in childhood. ADHD is characterised by a pattern of inattention, hyperactivity and/or impulsiveness that is more severe and more frequent than that typically found in children of the same age. The symptoms may interfere with the child's development and they have been associated with learning problems at school and a greater risk of developing addiction problems and risky behaviours.

ADHD is a complex disorder caused by multiple factors, making it difficult to identify the exact causes. Genetic and environmental factors, and their interactions, are known to contribute to this disorder. Environmental factors include maternal smoking during pregnancy and duration of breastfeeding. In recent years, the results of several studies have indicated that lifestyle factors—including the number of hours spent sleeping or watching television—may also influence the onset of ADHD. This finding is particularly important because these are factors that depend on us, which means they are modifiable.  

Lifestyle factors—including the number of hours spent sleeping or watching television—may also influence the onset of ADHD

The lifestyle factors most studied in ADHD have been the number of hours children sleep and the time they spend each day watching television. It is known that lack of sleep and excessive time spent watching television in childhood are factors that increase the risk of developing ADHD. However, other very common childhood activities have received less attention. Until recently, no study had analysed the possible influence on the development of ADHD of engaging in cognitively stimulating activities (such as reading or doing puzzles) or extracurricular physical activity.

In a recently published study, we investigated the association between several lifestyle factors in children aged four years and ADHD symptoms in the same cohort at age seven.

At this video, the researcher Gabriela Prado introduces the new prospective study

In addition to analysing the time the children spent sleeping and watching television, we also assessed the time they spent on cognitively stimulating activities and extracurricular physical activity.  We studied data from over 800 children who are participating in the INMA Project (Childhood and the Environment). When the children were four years of age, their parents answered a questionnaire about the time they were spending on different activities. Later, at seven years of age, the children were screened for ADHD symptoms using a questionnaire specifically designed to identify these problems.

Our findings suggest, for the first time, that spending more time on cognitively stimulating activities in childhood is associated with a lower risk of onset of ADHD symptoms

Our findings suggest, for the first time, that spending more time on cognitively stimulating activities (such as reading or doing puzzles) in childhood is associated with a lower risk of onset of ADHD symptoms. Our results also show a lower risk of ADHD in children who sleep more hours, in line with the findings of previous studies. By contrast, the appearance of ADHD symptoms was not associated in our study with either the time spent watching television or extracurricular physical activity.

In conclusion, our findings indicate that lifestyle factors may play an important role in the onset of ADHD. Specifically, they showed that better organisation of activities outside of school hours and ensuring adequate sleep may have a protective affect with respect to the onset of the symptoms of ADHD in children. Finally, these findings open the door to future lines of investigation. Owing to the design of our study, we were not able to analyse the effect of each type of cognitively stimulating activity separately. Consequently, it was not possible to identify which one had the greatest effect: for example, whether reading had a greater effect than doing puzzles.  Additional research is, therefore, needed to evaluate these activities in greater detail.