Adults who have been diagnosed with ADHD may have an increased likelihood of developing dementia.
Research indicates that individuals who receive a diagnosis of attention deficit hyperactivity disorder (ADHD) in adulthood may have an increased likelihood of developing dementia in the future.
The study did not definitively prove a causal relationship, but experts urge for further investigation into potential connections and the potential of ADHD medication to reduce dementia risk.
The findings are based on an examination of the medical histories of over 100,000 individuals. The study revealed that individuals who were diagnosed with ADHD as adults have a significantly higher chance of being diagnosed with dementia in their later years, with a risk almost three times higher.
The researchers state that the mechanisms of adult ADHD may hinder the brain’s ability to compensate for potential occurrences such as neurodegeneration or changes in blood flow that can occur later in life.
Dr. Stephen Levine, the lead author of the study at the University of Haifa, stated that this aligns with the main finding that adult ADHD raises the risk of dementia, with some limited evidence of a potential reverse causation.
According to a study published in the journal Jama Network Open, researchers examined electronic health records from Meuhedet Healthcare Services, a nonprofit health maintenance organization (HMO) in Israel. Individuals with a preexisting diagnosis of ADHD or dementia were not included in the study.
The researchers analyzed data from 109,218 individuals with an average age of 57.7 at the start of the study in January 2003. They followed their records until the earliest occurrence of death, leaving the HMO, being diagnosed with dementia, or the end of the study in February 2020.
During the study, it was found that out of 730 individuals, 96 (13%) were diagnosed with both adult ADHD and dementia. In comparison, among those who were not diagnosed with adult ADHD, there were 7,630 cases (7%) of dementia.
After considering variables such as age, gender, socioeconomic status, smoking, and other health conditions, the researchers discovered that individuals diagnosed with adult ADHD during the study were 2.77 times more likely to be diagnosed with dementia.
The findings also indicated that medication for ADHD altered the situation.
The team stated that there was no definitive link between ADHD and the risk of developing dementia in individuals who have taken psychostimulant medication for ADHD. They expressed that more research is needed to fully understand this finding.
Yet, Levine mentioned that the group was unable to determine if the findings also applied to ADHD in children and the research was not able to establish a causal relationship.
Roxana O Carare, a professor at the University of Southampton, who was not part of the research, also emphasized the same idea and proposed further investigation into the potential connection between changes in neurotransmitter levels in the brain, as seen in ADHD, and an increased risk for developing dementia.
However, Prof Chris Hollis, of the University of Nottingham, said there could be a number of factors muddying the waters. “Those adults who seek and receive an ADHD diagnosis are also more likely to be assessed for other cognitive/neuropsychiatric conditions including dementia,” he said, adding that it would also be reassuring if dementia diagnosis was independently confirmed by brain imaging.
“It is important for patients with ADHD to not be alarmed,” stated the speaker. “Further investigation is needed to confirm this connection, and if it is confirmed, a significant question would be whether treating ADHD can reduce this potential risk.”
According to Henry Shelford, the CEO of ADHD UK, an important finding from the research is the necessity to gain a better understanding of ADHD and its secondary impacts. He expressed concern that ADHD is currently not receiving adequate recognition in the UK and is lacking in-depth research.