UN Secretary-General Antonio Guterres on Wednesday called for more attention directed to people's mental health, especially that of young people.

"For too long, mental health has been mostly an afterthought, despite its overwhelming impacts on communities and young people, everywhere," Guterres said in a message in observance of the World Mental Health Day.

About one in five young people experiences mental health problems; half of all mental health conditions start by the age of 14 but most cases are undetected and untreated, according to the UN chief.

Poor mental health during adolescence has an impact on educational achievement and increases the risk of alcohol and substance use and violent behavior, he said, adding that suicide is a leading cause of death in young people.

With regard to adults' mental health, he said millions of people are caught up in conflict and disasters, putting them at risk of a range of long-term mental health problems; violence against women -- physical, sexual and psychological -- results in lasting scars, including post-traumatic stress disorder.

Recalling a great deal of mental health conditions are both preventable and treatable, Guterres stressed healthy societies require greater integration of mental health into broader health and social care systems, under the umbrella of universal health coverage.

The UN chief reiterated the UN's commitment to creating a world where everyone, everywhere has someone to turn to in support of their mental health by 2030. "It is time to act on mental health."

The theme of World Mental Health Day this year is young people and mental health in a changing world.

Much can be done to help build mental resilience from an early age to help prevent mental distress and illness among adolescents and young adults, and to manage and recover from mental illness, the World Health Organization noted on its webpage dedicated to the occasion.

The day is observed on Oct 10 every year, with the overall objective of raising awareness of mental health issues around the world and mobilizing efforts in support of mental health.

It also provides an opportunity for all stakeholders working on mental health issues to talk about their work, and what more needs to be done to make mental health care a reality for people worldwide.