A team of Briton researchers has recently found that one in four adolescent girls, especially poor, are at an increased risk of depression.
The researchers from the University of Liverpool and University College London found that a quarter of girls (24 percent) and one in 10 boys (9 percent) are depressed at age 14.
Lead author Dr Praveetha Patalay said that in the recent years there has been a growing policy focus on children's mental health. However, there has been a lack of nationally representative estimates of mental health problems for this generation.
The team analysed information on more than 10,000 children born in 2000-01.
Parents reported on their children's mental health at ages three, five, seven, 11 and 14.
Then, when the children reached 14, they were themselves asked questions about their depressive symptoms.
Based on the emotional problems of 14-year-olds, the findings indicated that 24 percent of girls and nine percent of boys suffer from depression.
The team also investigated the links between depressive symptoms and family income.
Behaviour problems, such as acting out, fighting and being rebellious decreased from infancy to age 5, but then increased to age 14. Boys were more likely than girls to have behaviour problems throughout childhood and early adolescence.
The new research also suggested that signs of depression are generally more common among children from poorer families, they explained.
The research appears in National Children's Bureau journal.