Lessons in emotional and mental health should be mandatory for all secondary schools in Wales, a charity has said.
Samaritans Cymru said pupils should be taught how to cope with life events and ask for emotional support in a bid to reduce emotional distress and stamp out stigma surrounding mental health.
Five Cardiff secondary schools have taken part in a pilot using lesson plans written by the charity.
The Welsh Government said it would make an announcement on the issue shortly.
A spokesman said: "As we move forward with the development of the new curriculum, we will be exploring how the education and health sectors can support all learners to become healthy, confident individuals.
"The education secretary and her health counterpart have been considering how emotional resilience and mental health input can be strengthened in school settings and a formal announcement is to be made shortly."
Currently in Wales, PSE (personal and social education) is compulsory for all pupils aged seven to 16 and covers an extensive range of topics including sex education, diversity, spiritual development and self-esteem.
But Samaritans Cymru said emotional and mental health lessons were often excluded and a spokeswoman said teachers were sometimes anxious about using the wrong terminology when talking about mental health.
The charity's executive director for Wales, Sarah Stone, said: "We must embed a public health approach to mental health by placing a primary focus on prevention rather than cure alone.
"Investment in prevention and early intervention can reduce human, social and economic costs.
"With half of all mental health problems beginning by the age of 14, the case for this approach is clear; school years are the crucial opportunity to equip children and young people with the skills they need."
During the past school year, teachers at Greenhill Special School, Cathays High School, Fitzalan High School, Cardiff High School and Corpus Christi High School, took part in a pilot called Deal (developing emotional awareness and listening), using teaching resources provided by the charity.
Teacher Laura-Cerys Williams, of Fitzalan High School, said: "Pupils enjoyed the sessions due to their interactivity and staff found the sessions very easy to deliver.
"Following the pilot, the students have a better awareness of mental health. We are planning on continuing to use some of the resources in our year seven, eight and nine lessons."
The charity said its most recent figures showed in 2015 more than 1,000 young people out of 18,000 referred to mental health services in 2016 waited more than six months for a first appointment.
Research by the NSPCC has found 1,193 young people were admitted to A&E departments in Wales because of self-harm in 2015 - an increase of 41% in three years.