Tackling the emotional and mental health issues among children and young people must be treated as a national priority, according to a report.
The Welsh Government's Children, Young People and Education committee identified an "urgent need" to invest in preventative and early intervention services.
It is estimated by the age of 14, half of all mental health problems in children will have already begun.
The report found the distress suffered by many children and young people could be reduced or even avoided if they had access to the right support in schools, including early intervention and preventative services.
Embedding mental health into the new curriculum and reducing the stigma associated with mental ill health were other recommendations to help improve well-being.
It is now calling on the Welsh Government to make urgent improvements to early intervention in children and young people.
How are some schools already tackling mental health?
By ITV Wales' Rob Shelley:
From the outside, Ysgol Pen y Bryn is a perfectly normal, rather well kept primary school in Colwyn Bay.
But if you look through the windows when it's time to learn, there's a quiet revolution going on behind the glass.
A smallish classroom, full of 30 ten and 11-year-olds - and the noise of pretty much all of them talking.
And then - some sort of alchemy happens. Deputy head Tabitha Sawyer begins a couple of exercises in mindfulness: getting her class to think about the way they're sitting, their breathing, to simply be in the moment.
The silence is impressive. Not because of the terrors of some Victorian schoolroom - but because the level of thought and concentration's written on a load of little faces.
You wouldn't start running, or play sport without some kind of warm up first; this works on exactly the same principle. At Ysgol y Bryn, there's no age limit for mindfulness - even the five year olds do it. But the idea behind it is to - well, be your own mechanic. See how your motor's running. Step outside of yourself and question how you are.
It sounds abstract: actually, it's a combination of meditation and concentration. Ten year old Ruby said, "When my brothers are really annoying I just go somewhere were it's quiet and practice my mindfulness and it really calms me down."
Twins Jennifer and Amelia say that - for Jennifer, it helps her when she's feeling a bit anxious, and for Amelia, it gives her a little time and space to breathe before exams so she can really focus.
Seeing a room full of primary school pupils both silent and focused on themselves and their preparation to learn is - across Wales - a rare enough sight. But maybe not for much longer. Maybe the next generation of students will focus on their minds - and their mental well being - just as much as an equation or the life of Henry VIII...
Responding to the Committee's report on improving mental health services, Prof Sally Holland, Children's Commissioner for Wales, said mental health services are delivered "too rigidly."