More: Twitter is flooded with messages of hope on Self-Harm Awareness Day

This came despite a warning in 2004 that some of the drugs could lead to suicidal behaviour, which led to an initial fall in prescriptions.

The research, Trends and patterns of antidepressant use in children and adolescents from five western countries, 2005–2012, which is published in the journal European Neuropsychopharmacology, also showed rises in Denmark (60 percent), Germany (49 percent), the U.S. (26 percent) and the Netherlands (17 percent) during the same period, reported the BBC.

"Antidepressant use amongst young people is and has been a matter of concern because of two reasons," said World Health Organization (WHO) director of mental health Dr. Shekhar Saxena. "One, are more people being prescribed antidepressants without sufficient reason? And second, can antidepressants do any major harm?"

The National Institute for Health and Care Excellence guidelines say antidepressants should not be used to treat mild depression in children.

Even when they are used to treat a child with moderate to severe depression this should only take place in combination with a concurrent psychological therapy.

More: U.K. schools can't cope with children's mental health issues

Dr. Maureen Baker, chairwoman of the Royal College of GPs, told The Independent that antidepressants would rarely be the first treatment option for children and young people, "but with such long waits for patients to see a specialist or to get a psychological therapy referral, drug therapy is sometimes seen as the only option for GPs to best support patients, who may be in extreme distress, and their family."

"We have been recommending for some time that in future, as part of an enhanced four-year training programme, all GP trainees should receive specialist-led training in mental health and child health," she said. "These measures truly would help to ensure that our young patients with mental health conditions receive the most appropriate treatment, and the same level of care as those with physical health problems, wherever in the country they live."

The answer is clear: more money needs to be invested in mental health. Young people don't have access to the talking therapies that could help get to the root cause of their depression so medication is the only alternative while they wait weeks (more likely months) to see a qualified mental health professional.

Hopefully the latest research will give countries the jolt they need to give the mental health of their young people the attention — and investment — it needs.

More: Kate Middleton delivers powerful speech about children's mental health