Fwiw, and I have no qualifications in this area beyond a family member committing suicide, I think three things should happen:
(i) children should be taught how to look after their own mental health in schools from an early age, just as they are taught about healthy eating and exercise so: some information on the way our brains work, mindfulness, resilience, basic CBT methods etc and the importance of exercise to produce endorphins etc, importance of social networks etc. Also , call me old fashioned but imho DC should be taught to challenge the values they are fed daily on social media, such as lip fillers will make you happy. Above all early intervention regarding mh issues should be paramount. The CAMHS system is so under resourced it's not fit for purpose but as most mh issues first manifest themselves at a young age, this is a ridiculous and dangerous false economy.
(ii) for low level mental illness (obviously not talking about serious conditions such as anorexia, bi-polar, schizophrenia etc which need professional help ) the dialogue should change from "reach out" to "how can I help myself?". I have a family member who works in this field who says there is an idea out there that somehow the answer to most mh problems lie outside of ourselves , that going in to a mental health hospital is an instant cure all (but there's no places because only the most serious cases are admitted) , when 80% of the time, treatment is most effective and enduring when the patients are taught to help themselves (with intermittent support from medical professionals where necessary). So a national campaign/ dialogue to spread this information would be helpful but it has to be backed up with better my support in the community
(iii) linked to the above must be hugely improved resources and support systems linked to primary care, accessible through a gp, such as talking therapies, self-help groups etc so people are given kick-starts and ongoing support while helping themselves. Why not have specialist mh GPS in each surgery?
That's not to say that one shouldn't reach out to a friend or colleague in need, but someone doing that ATM does so in the dark to some extent, not knowing where to turn. And when they do get the person who is suffering to reach out to a gp etc, depending on your post code, they have to wait for a long time or treatment is limited to half a dozen CBT sessions.
Above and beyond the practical points above, I think we need a wider discussion about societal values. Why are DC in the UK some of the unhappiest in the world? Is it because our society is dominated by consumerism? Is it because our playing fields and parks have been sold off to developers? Is it because our DC are under constant pressure to succeed academically , and are bombarded with unrealistic ideas of how they should look and behave on social media? Who in government is addressing this issue and how?