The more television adolescents watch, the more likely they are to develop attention and learning problems, and to do poorly in school in the long run, a new study confirms.
The findings, published in the Archives of Paediatrics and Adolescent Medicine, suggest that parents and teachers should encourageat-risk adolescents to watch less than three hours of TV a day.
Children in industrialised nations generally watch two or more hours of TV each day.
The New York researchers said that there was evidence linking TV-watching and poor academic and intellectual performance, but it was not clear whether the TV time led to school failure, whether children watched more TV if they were doing badly at school, or if there were factors such as poverty or neglect that might contribute to both increased TV viewing and learning problems.
To investigate, the researchers followed a community-based sample of 678 mother-child pairs from upstate New York beginning when the children were about 14 years old until they reached age 22.
The amount of TV children watched when they were 14 was positively linked with having attention problems later, not doing homework, being bored at school, not finishing high school, and "hating school", the researchers found.
The relationship between TV watching and school failure was stronger among children with higher-than-average verbal intelligence scores, and those whose parents had more than 12 years of education.
When children who watched less than two hours of TV at age 14 reduced their TV watching by an hour or more, they halved their risk of school failure, the researchers found.
But when 14-year-olds who watched less than two hours added one more daily hour of TV, they doubled their risk of academic failure at age 16.
Further analysis of the findings found that time spent watching TV probably contributed to learning and attention problems, rather than vice versa.
Future research should address "whether promoting opportunities for developmentally appropriate weekend, summer, and after-school extracurricular activities ... may help to reduce risk for the development of attention and learning difficulties during the adolescent years", the researchers conclude.
