One in two people globally will develop a mental health disorder by the age of 75, a study finds.
The researchers, from the University of Queensland and Harvard Medical School, analyzed data from 156,331 respondents in 29 countries who participated in 32 surveys as a part of the World Health Organization’s (WHO) World Mental Health Survey initiative.
The study, published in the journal Lancet Psychiatry, found that 46.4% of men and 53.1% of women will develop at least one mental disorder by age 75. Researchers also observed sex differences in the conditions affecting the participants.
The three most common mental health disorders among women are depression, specific phobia, defined as disabling anxiety that interferes with daily life, and post-traumatic stress disorder (PTSD). In comparison, men are most likely to develop alcohol abuse, depression, and specific phobia.
In half of people who develop a mental disorder before the age of 75, the condition usually emerges in adolescence or young adulthood.
"The peak age of first onset was at 15 years old, with a median age of onset of 19 for men and 20 for women," the study’s co-author, Professor John McGrath from UQ’s Queensland Brain Institute, said in a statement.
The findings emphasize the need for investing in mental health services with a particular focus on young people.
"Services need to be able to detect and treat common mental disorders promptly and be optimized to suit patients in these critical parts of their lives," said the study’s co-author, Professor Ronald Kessler from Harvard Medical School.
The surveys, however, were conducted over more than two decades and were based on retrospective reports. This could have led to the under-identification of more temporally distant events. Additionally, not all mental disorders were included in the survey, and the study did not consider comorbidity, although having one mental health disorder increases the risk of developing another one.
About one in five American adults (57.8 million people) lived with any mental illness (AMI) in 2021, with young adults aged 18 to 25 being the most affected.
The U.S. Preventive Services Task Force recommended in June that clinicians should screen adults ages 19 to 64 for anxiety disorders in primary care settings. All adults should also be screened for depression, the task force says.
The new study's authors say that a better understanding of the age at which these disorders commonly arise would allow tailoring health interventions and allocating resources to ensure appropriate and timely support for at-risk individuals.
- The Lancet Psychiatry. Age of onset and cumulative risk of mental disorders: a cross-national analysis of population surveys from 29 countries.
- The University of Queensland. Half the population to have a mental health disorder by 75.
- National Institute on Mental Health. Mental Illness.
- The U.S. Preventive Services Task Force. Anxiety Disorders in Adults: Screening.