Experts at the University of Manchester also found bullying and family bereavement were linked to suicides.
They investigated the suicides of 130 people under 20 in England between January 2014 and April 2015.
In February, figures published by the Office for National Statistics revealed an increase in youth suicides.
There were 201 people aged between 10 and 19 who killed themselves in 2014 in the UK – up from 179 in 2013.
It comes as separate Office for National Statistics figures, published this week, suggested student suicides have risen to their highest level since at least 2007.
Their findings showed:
◾36% had a physical health condition such as acne or asthma
◾29% were facing exams or exam results; four died on an exam day or the day after
◾28% had been bereaved
◾22% had been bullied, mostly face to face.
The study also found that 23% had used the internet in relation to suicide – including searching for methods or posting suicidal thoughts. Picture Louis Appleby supporting State of Mind
Speaking about the report’s findings, lead researcher Professor Louis Appleby said: “There are often family problems such as drug misuse or domestic violence and more recent stresses such as bullying or bereavement, leading to a ‘final straw’ factor such as an exam or relationship breakdown.”
“I think the numbers are the tip of the iceberg,” says Ged Flynn, chief executive of Papyrus, an anti-suicide charity.
Its support service, Hopeline UK, has seen a large rise in contacts from young people and parents in recent years, quadrupling since 2013.
It says that most of the calls, texts and emails it receives relate to exam stresses.
“I think the pressure on young people in increasing,” says Mr Flynn. “Peer pressure – from family, teachers and friends – has always been there, but it does seem to be increasing.
“And I think the need to be liked, the need to be popular, the need to be happy, is fairly universal. And it’s unrealistic.”