Washington: Adolescent girls who were expelled, suspended or dropped out of school by the 12th grade were more likely to be highly depressed by 21 years than girls who had none of these problems.

New research showed that girls who had such problems in elementary school also were at increased risk for depression in early adulthood.

"For girls there are broader implications of school failure," said Carolyn McCarty, a Washington University professor of paediatrics and co-author of the study.

"We already know that it leads to more poverty, higher rates of being on public assistance and lower rates of job stability. And now this study shows it is having mental health implications for girls."

The study showed that girls expelled from school were more than twice as likely to suffer depression - 44 percent compared to 20 percent of girls who were not expelled.

Thirty-three percent of the girls who dropped out of school later became depressed compared to 19 percent who were not dropouts. Twenty-eight percent of the girls who were suspended later suffered depression versus 19 percent of girls who weren't suspended.

Overall, 45 percent of the girls and 68 percent of the boys in the study experienced a major school failure, but McCarty said these rates were not surprising since the participants in the study came from high-crime neighbourhoods.

"One reason may be that school failure stigmatises girls more strongly or is harder for them to overcome. We do know that girls with conduct problems, such as school failure, tend to have long-term problems with cascading effects," said McCarty.

The research relied on students drawn from 18 Seattle schools in high-crime neighbourhoods to study the development of positive and antisocial behaviours.

Participants were almost equally divided by gender and identified themselves as white (46 percent), black (24 percent), Asian-American (21 percent), Native American (6 percent) and other groups (three percent). IANS