Study links ADHD to higher risk of later cognitive impairment

A large U.S. study found that adults diagnosed with attention-deficit/hyperactivity disorder were more likely than those without ADHD to develop cognitive impairment later in life, including mild cognitive impairment or dementia. Researchers also found a similar association among people with higher genetic risk for ADHD, but said the observational findings do not establish that ADHD causes cognitive decline. The analysis covered health records and genetic data for 187,341 adults aged 50 or older enrolled in the National Institutes of Health’s All of Us Research Program. Of those participants, 3,026 had an ADHD diagnosis. Cognitive impairment was recorded in 6.7% of participants with ADHD, compared with 3.4% of those without the diagnosis. After adjusting for factors including age, sex and health conditions, the study reported a hazard ratio of 4.60 for cognitive impairment among participants with ADHD compared with those without. In an analysis limited to dementia, the reported hazard ratio was 3.07. These estimates describe relative differences in the study’s observed outcomes, not an individual’s likelihood of developing dementia.