FINDINGS

ADHD and Brain Development

Crucial parts of the brains of children with attention-deficit hyperactivity disorder develop more slowly than other youngsters' brains, a phenomenon that earlier brain-imaging research missed, a new study says.

Developing more slowly in ADHD youngsters -- the lag can be as much as three years -- are brain regions that suppress inappropriate actions and thoughts, focus attention, remember things from moment to moment, work for reward, and control movement.

Researchers led by Philip Shaw of the National Institute of Mental Health reported the results yesterday in the Proceedings of the National Academy of Sciences.

The finding "could help to explain why many youth eventually seem to grow out of the disorder," Shaw said in a statement, although not all do. He said, however, that "brain imaging is still not ready for use as a diagnostic tool in ADHD. . . . It is not yet possible to detect such delay from the brain scans of just one individual."

The research team used scans to measure the cortex thickness at 40,000 points in the brains of 223 children with ADHD and 223 others who were developing normally. The scans were repeated two, three or four times at three-year intervals.

Sharp Minds With Beta Carotene?

Beta carotene taken as a dietary supplement for many years may protect against declines in memory, thinking and learning skills that often precede Alzheimer's disease, researchers said yesterday.

The study, in the Archives of Internal Medicine, pointed to a protective effect against cognitive decline in healthy men who look the antioxidant beta carotene for about 18 years, but not in men who took it for an average of one year.

"This is the first trial that has found any way to help your memory if you're healthy. I think it does tell us that we can change how our memory improves or worsens," said Francine Grodstein of Brigham and Women's Hospital, who led the study. Grodstein noted that taking beta carotene may raise the risk of lung cancer in smokers. In the study, a group of 4,052 men were randomly assigned in 1982 to take either 50 milligrams of beta carotene or a placebo every other day. Another 1,904 men were enrolled in the study between 1998 and 2001.

Men who took beta carotene for an average of 18 years recorded significantly higher scores on several cognitive tests -- particularly tests of verbal memory -- compared with those who took a placebo, the study found. In the short-term group, the men taking beta carotene did no better in cognitive tests.

Chocolate Drinks Go Way Back

Residents of Central America were enjoying chocolate drinks more than 3,000 years ago, half a millennium earlier than previously thought, new research shows.

Archaeologists led by John Henderson of Cornell University studied the remains of pottery used in the lower Ulua Valley in northern Honduras about 1100 B.C.

Residue from the pots contained theobromine, which occurs only in the cacao plant, the source of chocolate, the researchers wrote yesterday in the Proceedings of the National Academy of Sciences.

The find dates the first use of chocolate to about 500 years earlier than previously known, they said.

The style of the pottery indicates that cacao was served at important ceremonies to mark weddings and births, according to the authors.

-- From News Services