Mentally ill kids become less healthy adults

But because mental health problems peak early in life and can be identified, the researchers say that more investment in prompt mental health care could be used to prevent later diseases and lower societal healthcare costs.

"The same people who experience psychiatric conditions when they are young go on to experience excess age-related physical diseases and neurodegenerative diseases when they are older adults," explained Terrie Moffitt, the Nannerl O. Keohane professor of psychology and neuroscience at Duke, who is the senior author on both studies.

The findings in a paper appearing Feb. 17 in JAMA Psychiatry come from the long-term Dunedin Study, which has tested and monitored the health and wellbeing of a thousand New Zealanders born in 1972 and '73 from their birth to past age 45.

In middle age, the study participants who had a history of youthful psychopathology were aging at a faster pace, had declines in sensory, motor and cognitive functions, and were rated as looking older than their peers. This pattern held even after the data were controlled for health factors such as overweight, smoking, medications and prior physical disease. Their young mental health issues included mainly anxiety, depression, and substance abuse, but also schizophrenia.

"You can identify the people at risk for physical illnesses much earlier in life," said Jasmin Wertz, a postdoctoral researcher at Duke who led the study. "If you can improve their mental health in childhood and adolescence, it's possible that you might intervene to improve their later physical health and aging."

A related study by the same team that appeared in JAMA Network Open in January used a different approach and looked at 30 years of hospital records for 2.3 million New Zealanders aged 10 to 60 from 1988 to 2018. It also found a strong connection between early-life mental health diagnoses and later-life medical and neurological illnesses.

That analysis, led by former Duke postdoctoral researcher Leah Richmond-Rakerd, showed that young individuals with mental disorders were more likely to develop subsequent physical diseases and to die earlier than people without mental disorders. People with mental illnesses experienced more hospitalizations for physical conditions, spent more time in hospitals and accumulated more healthcare costs over the subsequent 30 years.

"Our healthcare system often divides treatment between the brain and the body, but integrating the two could benefit population health," said Richmond-Rakerd, who is now an assistant professor of psychology at the University of Michigan.

"Investing more resources in treating young people's mental-health problems is a window of opportunity to prevent future physical diseases in older adults," Moffitt said. "Young people with mental health problems go on to become very costly medical patients in later life."

In a 2019 commentary for JAMA Psychiatry, Moffitt and her research partner Avshalom Caspi, the Edward M. Arnett professor of psychology and neuroscience at Duke, made the argument that mental health providers have an opportunity to forestall later health problems and other social costs by intervening in the lives of younger people. Their body of work is showing that mental disorders can be reliably predicted from childhood risk factors such as poverty, maltreatment, low IQ, poor self-control and family mental health issues. And because populations in the developed world are becoming more dominated by older people, the time to make those investments in prevention is now, they said.

These studies were supported by the U.S. National Institute on Aging, the U.S. National Institute of Child Health and Development, and the UK Medical Research Council. Additional support came from the Jacobs Foundation, the Lundbeck Foundation and the New Zealand Health Research Council (R01-AG032282, R01-AG049789, MR/P005918, P30 AG028716, P30 AG034424, 15-265, R288-2018-380, P2C HD065563). The Dunedin Multidisciplinary Health and Development Study is supported by the New Zealand Health Research Council and New Zealand Ministry of Business, Innovation, and Employment.