Here are some startling figures for you to grapple with: the World Health Organisation (WHO) predicts that by 2030, depression will be the number one global health problem.
Globally, the organisation says that 20pc of children and teenagers will experience a disabling mental health problem. And doctors agree that the most common age of onset of major depression is around 13 or 14.
They're frightening statistics which leave us wondering: are we doing enough to safeguard our teenagers' mental health in a world where they face unprecedented pressures and challenges?
How would we know if a teenager was feeling overwhelmed by academic expectation, online bullying, family breakdown, pressures at home, or simply the everyday drama of growing up?
"Adolescence is a very vulnerable time," says Dr Tony Bates, a clinical psychologist who founded the organisation Headstrong, the National Centre for Youth Mental Health.
"A young boy or girl wakes up to the realisation that they are part of a much bigger world, and that world is full of things that are not right. It's full of injustice and of adults who are not the heroes they thought they were as children.
"There's a dawning awareness for them that this world is a bit of a mess and it's up to me to make my way in it, and the adults don't seem to understand what I'm going through.
"They want to be independent, but they are not quite ready for it yet. They are not yet men and women, so they really need the adults in their lives.
"On top of all that, they've got pressure at school, the dog has to be put down, someone they know is self-harming, they don't know if they are going to get jobs, and they have to deal with all of that as well as all the normal developmental stuff that is going on in their lives."
And given that the teenage years are naturally filled with ups and downs, is there any reliable way for parents to spot the warning signs of depression?
Dr Bates is anxious to stress that a lot of teenagers exhibit behaviour which might easily suggest a diagnosis of clinical depression, but in reality is a normal response to all the traumatic changes and challenges they're dealing with.
"We don't want to over-read normal behaviour," he says, "because a lot of the signs of depression – like sleeping too much, withdrawing from the world, losing interest in things, not eating or over-eating, loss of energy – well, I've raised three teens and you see all of that going on at certain times. We don't want to interpret what might just be a difficult time for someone as more than that.
"But whatever is going on, they do need us to be there for them. It's really important that we don't interpret their behaviour, when they're pushing us away, as actually wanting us to go away.
"They need us to be a steady presence in their lives, not to go away, not to stop believing in them, and not to abandon them."
Most experts are in agreement that for young people in crisis, medication, in the form of Prozac-type drugs from the SSRI family, prescribed by a GP, can be helpful. But most important is that teenagers in trouble have access to proper counselling, or at the very least, the support of a sympathetic adult who is capable of listening to them.
"Most teenagers who feel depressed feel it about something which is not working in their lives," says Dr Bates. "What they need is someone to listen to them and to work through those difficulties with them."
The government has been slow to respond to the growing crisis in youth mental health, and has been repeatedly castigated for failing to meet the targets set out in its policy document A Vision For Change. Services are improving, but child mental health teams remain understaffed.
"We were promised an injection of extra cash to pay for 150 posts in the 2012 budget, but recruitment has been extremely slow and our community teams are falling far short of the numbers and diversity skills needed," says Pippa Woolnough, campaign team leader and communications officer with Amnesty International Ireland.
"Only 63 child and adolescent mental health teams are in place, instead of the recommended 107. Of those that do exist, their staffing levels are less than two-thirds of what they should be."
Campaigners say there is a particular difficulty in treating 16- and 17-year-olds, who are regularly refused referral to the services because they fall between children's services and adult services. Despite this, there are encouraging signs that we are beginning to sit up and take notice of the growing crisis.
Organisations such as Reach, spunout.ie, and Headstrong, provide information and support networks across the country which young people – and their parents – can access for help.
Meanwhile, high-profile multimedia and poster campaigns have helped remove the stigma from mental illness for all ages. And that might just be the first step towards recovery.