Recent research has found that teenagers who have minor depression are at higher risk of mental health problems later in life.
The study was based on interviews with 750 14 to 16-year-olds who were then assessed again as adults.
It was found that 8% of participants had minor depression as teenagers. The risk of having major depression was four times higher than those who did not have signs of minor depression at the first interview.
Lucie Russell, director of campaigns at Young Minds, said the study highlighted the importance of giving teenagers the right support when problems first arise.
"Ensuring teachers, social workers and the rest of the children's workforce have the appropriate skills and knowledge to identify when a child is showing signs of depression will enable young people to get help early before problems escalate to crisis point."