Adults with intellectual and developmental disabilities (IDDs) are far more likely to experience anxiety and depression than the general population.

New national data from more than 44,000 US adults showed that those with IDDs were more than nine times as likely to report a diagnosis of anxiety or depression compared with their counterparts without functional limitations.

The disparities were even more pronounced when investigators examined daily symptoms. Individuals with IDDs were almost 18 times more likely to report daily depressive symptoms of depression than those without functional limitations — 25% vs just 1.4%. In addition, many individuals with IDDs delayed or did not seek mental health care because of cost considerations.

“Our findings paint a distressing picture of the mental health and healthcare for people with these disabilities in the United States,” senior author Dimitri Christakis, MD, MPH, and professor of pediatrics at the University of Washington School of Medicine in Seattle, said in a news release.

“Historically, society has not taken the needs of this population as seriously as it should, so in that respect, our findings aren’t surprising. But the scale of burden is shocking,” Christakis added.

The study was published online on February 20 in JAMA Network Open.

Excluded From National Surveillance Data

IDDs are a group of chronic, lifelong conditions that affect cognitive functioning and adaptive skills. Affected individuals have a higher risk for comorbid psychiatric conditions, and anxiety and mood disorders are the most common.

Previous disability studies have been limited in scope and have not fully addressed the mental health and health care disparities experienced by those with IDDs, the investigators noted. Compounding the issue, this population has largely been underrepresented in national health datasets.

Using data from the US National Health Interview Survey (NHIS), which was restructured in 2019 to include functional limitation criteria, the investigators aimed to assess the prevalence of anxiety and depression, mental health care use, and barriers to care among individuals with IDDs.

The investigators used NHIS data from 2021 to 2023 and included 44,478 adults (mean age: 49, 53% female, 63% White), representing 134.3 million US adults.

Likely cases of IDDs were determined using the Washington Group Short Set criteria, which assesses self-reported functional and cognitive difficulty. They identified 796 adults with IDDs, representing a weighted population of 2.9 million.

Participants were asked if they had received a diagnosis of anxiety or depression, their current psychiatric medication use, how often they felt anxious or depressed, and the severity of their symptoms.

They also reported past-year use of mental health care and whether they faced financial barriers accessing those services.

Weighted prevalence estimates and multivariable logistic regression models were used to evaluate associations between IDD status and outcomes. Models were adjusted for socioeconomic and demographic factors.

Access to Care Inequities

Of those with IDDs, 57.1% reported a depression diagnosis compared with 9.9% of adults without functional limitations (adjusted odds ratio [AOR], 9.78; 95% CI, 8.08-11.83). There was also a higher prevalence of diagnosed anxiety among adults with IDDs (AOR, 9.41; 95% CI, 7.71-11.49).

Symptom burden was higher among adults with IDDs; 50.8% reported daily symptoms of anxiety compared with 7.9% of those without a disability. Adults with IDDs were nearly 18 times more likely to report daily symptoms of depression (AOR, 17.73; 95% CI, 13.84-22.72). Those with disabilities also reported higher symptom severity for both anxiety and depression.

In addition, adults with IDDs were significantly more likely than the general population to receive psychiatric drugs for depression (AOR, 8.88; 95% CI, 7.28-10.83) and anxiety (AOR, 7.02; 95% CI, 5.73-8.60).

A high proportion of those with IDDs also reported seeking therapy or counseling in the past year. However, many face difficulty accessing care and are roughly five times more likely to delay or avoid mental health care due to costs.

“Our data suggest that, even with coverage, people with intellectual disabilities face significant out-of-pocket costs and difficulty finding providers who accept their insurance and have appropriate expertise in treating their symptoms,” Christakis said.

Limitations of the study were that adults with IDDs were identified by functional limitation survey criteria rather than clinical diagnosis, which might lead to misclassification, and the fact that mental health outcomes were self-reported.

The authors called for higher reimbursement rates for mental health providers who care for people with IDDs, more research and resources to increase access to evidence-based therapy, and for disability status to be included in national datasets.

“Most of us are keenly aware of the mental health crisis confronting US teenagers today. There is also one affecting people with intellectual and developmental disabilities,” Christakis said.

The study was supported by Special Olympics Health, made possible by the Golisano Foundation and the CDC. See the study for author disclosures.