A new global study has found that one in two people will be diagnosed with at least one mental health disorder by the age of 75. Given that many of these disorders first appear in childhood or early adulthood, the researchers say their findings highlight the importance of timely interventions tailored to at-risk people.
Mental health disorders aren’t uncommon; they affect a large number of people worldwide, interfering with their well-being, work, and social lives. Ensuring that services are available to effectively diagnose and treat mental illness requires an in-depth understanding of its scale, who it’s likely to affect and when.
A new study co-led by researchers from the University of Queensland and Harvard Medical School has analyzed data from 156,331 respondents taken from 32 World Health Organization (WHO) World Mental Health surveys across 29 countries, including 12 low- and middle-income countries and 17 high-income countries between 2001 and 2022.
A fully structured psychiatric diagnosis interview was used to assess the age of onset, lifetime prevalence, and risk of 13 mental disorders included in the DSM-IV, the fourth edition of the official diagnostic manual of the American Psychiatric Association, until age 75.
The included disorders were panic disorder or agoraphobia, generalized anxiety disorder, post-traumatic stress disorder (PTSD), social phobia, specific phobia, major depressive disorder, bipolar disorder, alcohol abuse disorder, alcohol dependence disorder, drug abuse disorder, drug dependence disorder, ADHD, and intermittent explosive disorder.
The results demonstrated a high prevalence of mental health disorders, with approximately 50% of the population expected to develop at least one disorder by age 75.
“The most common were mood disorders such as major depression or anxiety,” said John McGrath, lead author of the study. “We also found the risk of certain mental disorders differed by sex.”
Among women, the three most common mental health disorders were depression, specific phobia (disabling anxiety that interferes with daily life), and PTSD. The three most common disorders for men were alcohol abuse, depression, and specific phobia.
A key finding of the study, say the researchers, was that a “substantial proportion” of mental disorders were likely to first appear in childhood, adolescence or young adulthood. In addition to traditional childhood-onset disorders such as ADHD, common mental disorders like major depressive disorder, generalized anxiety disorder and panic disorder were often found to have their first onset between childhood and early 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,” McGrath said. “This lends weight to the need to invest in basic neuroscience to understand why these disorders develop.”
Given the young age of onset for some disorders, the researchers say that mental health service providers must focus particularly on providing early diagnosis and intervention to young people.
“Services need to be able to detect and treat common mental disorders promptly and be optimized to suit these patients in these critical parts of their lives,” said Ronald Kessler, one of the study’s co-authors. “By understanding the age at which these disorders commonly arise, we can tailor public health interventions and allocate resources to ensure that appropriate and timely support is available to individuals at risk.”
The study was published in the journal The Lancet Psychiatry.
Source: University of Queensland
