In Brief

Adults with attention-deficit hyper-activity disorder (ADHD) are ruled by their impulses when faced with a problem to solve, says a study in the September Neuropsychology (Vol. 21, No. 5). A study group composed of adults with ADHD and controls demonstrated a marked difference in problem-solving strategies, with the ADHD group chucking planning out the window in favor of haste.

"You could say they favored speed over accuracy," says study author Susan Young, PhD, a clinical psychologist at the Institute of Psychiatry in London.

Young and her team tested the groups with an assignment known as the Tower of London task. In the task, participants are shown three rods on a computer screen with rings of various sizes hooped around the rods. By touching the screen, participants can move the rings around to different rods and stack them on top of each other in various arrangements. At the top of the screen is a target arrangement that participants are supposed to match by moving the rings around. There are varying degrees of difficulty, with different puzzles requiring a minimum of three moves, four moves or five moves.

Young and her team initially tested the participants' motor speed as they touched the screens. Then, she measured their planning times, or the period between the puzzle's appearance on the screen and participants' first move.

On the lower-difficulty puzzles, the ADHD group and the control group spent about the same amount of time planning for the puzzles. But as the difficulty increased, the control group took more and more time to plan, while the ADHD group plowed through at a constant planning pace. As a result, the ADHD group's overall accuracy on the puzzles declined.

"The people with ADHD didn't give themselves any time to figure out what they were going to do," Young says. "Instead, they employed ineffective, haphazard strategies."

Using measurements from the DSM-IV checklist, Young was able to correlate this lack of planning with symptoms of impulsivity. So her results might not be limited to people with ADHD, she says, but could also include other cognitive disorders characterized by impulsivity.

--M. Price