Children and teenagers who watch a lot of television may be more likely to display antisocial and criminal behaviour later in life, a new study suggests.

Scientists in New Zealand followed the progress of around 1,000 children born in the early 1970s. The children's television viewing habits were assessed every two years, from when they were five years old until they were 15.

The study found that those who had watched the most television in their younger years were more likely to have a criminal conviction in adulthood.

In fact, the risk of having a conviction jumped by some 30% for every hour that children spent watching television on a normal weeknight.

The study also found that those who watched a lot of television when they were younger were more likely to have antisocial and aggressive personality traits, including a psychiatric disorder characterised by patterns of antisocial behaviour.

The scientists from the University of Otago noted that these results could not be explained by other factors such as parenting methods, socioeconomic status or aggressive behaviour in childhood.

According to the study's co-author, Lindsay Robertson, the research did not find that children who already had antisocial traits tended to watch more television.

"Rather, children who watched a lot of television were likely to go on to manifest antisocial behaviour and personality traits."

The scientists acknowledged that the study does not prove that watching too much television causes antisocial behaviour. However, they noted that the findings are consistent with other studies, which have found that too much television can have long-term effects on behaviour.

"Antisocial behaviour is a major problem for society. While we're not saying that television causes all antisocial behaviour, our findings do suggest that reducing TV viewing could go some way towards reducing rates of antisocial behaviour in society," they said.

Details of these findings are published in the journal, Pediatrics.