Researchers from The University of Queensland and Harvard Medical School, in a collaborative global study, have discovered that one in two people will develop a mental health disorder in their lifetime.

Professors John McGrath of UQ’s Queensland Brain Institute and Ronald Kessler of Harvard Medical School, together with experts from 27 additional nations, examined data from over 150,000 adults spanning 29 countries from 2001 to 2022. This data was sourced from the largest-ever coordinated series of face-to-face interviews – the World Health Organisation’s World Mental Health Survey initiative.

Lead author Professor McGrath said the results demonstrate the high prevalence of mental health disorders, with 50 percent of the population developing at least one disorder by the age of 75.

“The most common were mood disorders such as major depression or anxiety,” Professor McGrath said. “We also found the risk of certain mental disorders differed by sex.”

The 3 most common mental health disorders among women:

• Depression

• Specific phobia (a disabling anxiety that interferes with daily life)

• Post-traumatic stress (PTSD)

The 3 most common mental health disorders among men:

• Alcohol abuse

• Depression

• Specific phobia

The research also found mental health disorders typically first emerge in childhood, 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,” Professor McGrath said. “This lends weight to the need to invest in basic neuroscience to understand why these disorders develop.”

McGrath, J. J., Al-Hamzawi, A., Alonso, J., Altwaijri, Y., Andrade, L. H., Bromet, E. J., ... & Zaslavsky, A. M. (2023). Age of onset and cumulative risk of mental disorders: a cross-national analysis of population surveys from 29 countries. The Lancet Psychiatry, 10(9), 668-681. doi:https://doi.org/10.1016/S2215-0366(23)00193-1