WEDNESDAY, Jan. 19 (HealthDay News) -- Adults with attention-deficit hyperactivity disorder (ADHD) have a more than threefold increased risk of developing a common form of degenerative dementia called dementia with lewy bodies (DLB), a new study says.
"Lewy bodies" -- abnormal clumps of protein deposits that develop inside nerve cells and disrupt brain functioning -- are found in people with Parkinson's disease and some other neurological disorders.
Researchers in Argentina looked at 109 patients (average age 75) who had dementia with lewy bodies, 251 with Alzheimer's disease and a control group of 149 healthy people (average age 74 in both the latter groups). They found that 48 percent of patients who had dementia with lewy bodies had previously suffered from adult ADHD, compared with 15 percent of those with Alzheimer's and in the control group.
The study appears in the January issue of the European Journal of Neurology.
Dementia with lewy bodies "is thought to account for around 10 percent of dementia cases in older people, but it tends to be under-diagnosed because it shares some characteristics with both Alzheimer's and Parkinson's," lead author Dr. Angel Golimstok said in a journal news release.
"It is a degenerative neurological condition that has a progressive and disabling effect on a person's mental and physical skills," Golimstok added. "Other symptoms can include recurrent and realistic visual hallucinations, fluctuations in the person's everyday abilities and spontaneous movement problems similar to those observed in Parkinson's."
It's believed that the same neurotransmitter pathway problems are involved in the development of ADHD and DLB, so Golimstok's team wanted to test the theory that ADHD often precedes DLB.
"We believe that our study is the first of its kind to examine the clinical association between adult ADHD symptoms and DLB and that it has established a clear link between the two conditions," Golimstok said.
The U.S. National Institute of Neurological Disorders and Stroke has more about dementia with Lewy bodies.