A significant number of adults with developmental disabilities have no regular, daily activities, a situation that’s symptomatic of larger problems, new research indicates.

The finding comes from a survey of nearly 800 siblings of adults with intellectual and developmental disabilities from across the country. In nearly 13 percent of cases, siblings reported that their brothers and sisters with disabilities were not involved in any sort of routine vocational or educational activities.

And the number is likely higher than that, researchers said, noting that based on how they solicited responses to their survey, participants likely tended to be higher earners and more educated than the population as whole.

Overall, those with nothing to do tended to be individuals with more emotional, behavioral or health problems and lower functioning abilities, according to the study published recently in the American Journal on Intellectual and Developmental Disabilities.

They were also more likely to have parents who were less able to provide care and be underserved by the community. Strikingly, the researchers said that adults with nothing to do had three times the number of unmet needs for services as compared to those who were working, volunteering or attending school.

“The lack of any vocational or educational activity may itself constitute a marker for those adults with intellectual and developmental disabilities who are most in need of intervention and formal supports,” wrote lead author Julie Lounds Taylor of Vanderbilt University and her colleagues in the study.

Beyond the impact on individuals with disabilities themselves, the researchers point out that siblings of those without any regular activities reported having poorer mental and physical health than other siblings as well as weak relationships with their brother or sister, calling into question their viability as long-term caregivers.

“Ultimately, if we are going to help adults with disabilities (and their loved ones) live more fulfilling lives, we need to work harder to understand the characteristics and effects that occur when adults with disabilities are doing nothing,” the researchers wrote.