CHICAGO, Jan. 14 (Xinhua) -- A study by researchers at the University of Michigan (UM) indicates that people who experience psychiatric conditions when they are young are likely to experience excess age-related physical diseases when they are older.

The researchers conducted a nationwide hospital-register study of 2.3 million New Zealanders aged 10 to 60 years at baseline that have been followed across three decades from 1988 to 2018, and collected information about hospital admissions for different mental disorders, such as substance use disorders, psychotic disorders, mood disorders, anxiety disorders and self-harm behavior. In addition, researchers collected information about hospital admissions for different chronic physical diseases, ranging from coronary heart disease to cancer.

Across the 30-year period, individuals with mental disorders were more likely to develop subsequent physical diseases and they also died earlier than people without mental disorders, the study showed. They also experienced more medical hospitalizations, spent more time in hospitals for physical-disease treatment and accumulated more associated health care costs.

And these associations were present across all age groups and in both men and women.

The findings indicate that addressing mental health problems in early life might be a window of opportunity for preventing future physical diseases, the researchers said. They also suggest the importance of joined-up services, or integrated care.

"Our health care system often divides treatment between the brain and the body," said Leah Richmond-Rakerd, UM assistant professor of psychology. "Integrating the two could benefit population health."

The study, posted on UM's website on Wednesday, has been published in the journal JAMA Network Open.