Toronto, Aug 29 - Almost 15 percent of pre-school students are beset with high levels of depression and anxiety, according to a new study.

The investigation, which was carried out over a period of five years, also found that such children are more likely to have mothers with a history of depression.

The study was conducted by researchers from the Universites of Montreal, Laval and McGill, as well as Inserm (Institut national de la sante et de la recherche medicale) France, Carnegie Mellon University in the US and University College, Dublin Ireland.

'As early as the first year of life, there are indications that some children have more risks than others to develop high levels of depression and anxiety,' says study co-author Sylvana M. Cote, professor in social and preventive medicine at Montreal University.

'Difficult temperament at five months was the most important predictor of depression and anxiety in children,' Cote said.