New York, May 22 (IANS): Mothers who have trouble sleeping may engage in more permissive parenting, that is parenting marked by lenient or liberal discipline, says a study.

This type of lenient parenting, especially during the adolescent years, may increase the risk of problematic or risky behaviour among children including affiliation with deviant peers, engaging in delinquent behaviour, or substance use and abuse, according to the researchers.

"We found that when mothers were not receiving enough sleep, or receiving poor quality sleep, it had an effect on their levels of permissiveness with their adolescents," said Kelly Tu from the University of Illinois at Urbana-Champaign in the US.

"It may be that they're more irritable, experiencing impaired attention, or so over-tired that they are less consistent in their parenting. But on the plus side, we also find that mothers who are receiving adequate sleep are less likely to be permissive with their adolescents," she added.

The study, published in the Journal of Sleep Research, focused on the effect of maternal sleep on parenting of adolescents.

Tu explained that during adolescence -- 11 to 18 years of age -- parental involvement is an important factor regarding how well their kids are adjusting socially, emotionally and behaviourally.

"Given that permissive parenting may heighten the risk of adolescents' risky behaviours, we wanted to take a step back to ask what's driving these permissive parenting behaviours, and to see if sleep could be a contributing factor," Tu said.

In order to examine maternal sleep duration and quality, the study included 234 mothers who were asked to wear actigraphs -- a wristwatch-like device -- for seven consecutive nights which tracked their movements at night and determined whether there was a disruption in sleep.

Simultaneously, the adolescent children of the participants of an average age of 15 years completed questionnaires about how they perceived their mothers' parenting.

The results showed that mothers who had a longer duration of sleep or who were able to fall asleep easily, had adolescents who reported lower levels of permissive parenting.

The study is significant as it points out the need for self-care and the importance of sleep, according to Tu.