Attention Deficit Hyperactivity Disorder (ADHD) drugs like Ritalin could be effective against obesity. Severely obese might lack the will power to lose weight because of a chemical imbalance in the brain caused by the problem.

Those suffering from ADHD cannot respond to the signals in their brains that tell them when they are hungry and when they are full. There is a lack of dopamine and noradrenalin receptors in the area of their brain that determines how they attach and detach their attention, it has been found.

Consequently, their stomachs stretch and they can tolerate a degree of fullness that would make the average person throw up. Hence people with ADHD are more likely to develop weight problems than those without it. 

In the circumstances, treating ADHD with drugs like Ritalin could be one way of combating obesity. In fact the improvement is dramatic, says Lance Levy, a Toronto specialist in nutritional medicine.

"ADHD is a primary cause of failing to lose weight for tens of thousands of people," said Dr. Levy, who is with the Nutritional and Eating Disorders Clinic. "Obese people are three to five times more likely to have it than the regular population. And if you treat them, you will see a significant weight loss."

Dr. Levy and his co-authors - psychologist John Fleming and dietitian Doreen Klar - have just published their groundbreaking research in the International Journal of Obesity, a peer-reviewed scholarly journal.