ADHD Rates, Adverse Outcomes Elevated in Adults With Autism

TOPLINE:

Attention-deficit/hyperactivity disorder (ADHD) rates were 24%-37% higher in adults with autism than the general population and having both conditions was linked to worse outcomes, a new cohort study showed.

METHODOLOGY:

• This population-based cohort study included more than 3.5 million Medicaid-enrolled adults aged 18 years or older (mean age, 33.5 years; 53% women; 60% White individuals) from 2008 to 2019 across all 50 states and Washington, DC.
• Participants included adults with autism with and without intellectual disability (ID), adults with ID without autism, and a random sample of Medicaid-enrolled adults from the general population.
• Outcomes included prevalence rates of co-occurring ADHD, prescriptions of ADHD medications, substance use, cardiovascular conditions, and injury across all groups.

TAKEAWAY:

• ADHD rates were 2.7% in the general population compared with 27% in individuals with autism without ID (prevalence ratio [PR], 5.1; 95% CI, 4.4-5.9), 40% in those with autism with ID (PR, 6.8; 95% CI, 6.0-7.7), and 19% in those with ID without autism (PR, 4.4; 95% CI, 4.0-5.0).
• Adults with ADHD had higher rates of substance use (PR, 2.4-3.1), cardiovascular conditions (PR, 1.2-1.4), and injury (PR, 1.2-1.5) across all diagnostic groups than those without ADHD.
• Although rates of ADHD medication prescriptions varied across the groups, the prescriptions were linked to lower rates of cardiovascular conditions and injury.
• Substance use was also lower among adults prescribed ADHD medications, except for those with autism and with ID.

IN PRACTICE:

“At a clinical level, we need to make sure that an increased number of patients with co-occurring ADHD in adulthood have access to support programs that provide autism as well as ADHD services across the lifespan of these patients,” lead author Benjamin E. Yerys, PhD, Children’s Hospital of Philadelphia, Philadelphia, said in a press release.

“Psychiatric education has to emphasize the importance of neurodevelopmental concepts if we are to avoid such clinical pitfalls as misdiagnosis and missed diagnosis to ensure appropriate treatment for treatable disorders,” Ken Courtenay, MSc, UCL Division of Psychiatry, London, England, wrote in an accompanying editorial.

SOURCE:

The study and editorial were published online on February 12 in JAMA Network Open.

LIMITATIONS:

This study was limited by potential underdiagnosis of various conditions due to incomplete or missing claims data. Furthermore, the Medicaid population may not have been representative of the broader non–Medicaid-enrolled population. ADHD medication prescriptions served as a suboptimal proxy for medication usage, as actual medication adherence could not be independently confirmed. The binary classification of ADHD medication prescriptions as present or absent did not account for variations in continuous vs time-limited use of medications. In addition, race and ethnicity data were not fully populated in Medicaid files.

DISCLOSURES:

The study received funds from the Health Resources and Services Administration of the US Department of Health and Human Services. Three of the four investigators reported receiving grants from various sources. Yerys also reported serving as a grant reviewer and receiving personal fees from an ADHD center outside the submitted work. Full details are listed in the original article. Courtenay reported no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.