Major league baseball authorized nearly eight per cent of its players to use drugs for ADHD last season, which allowed them to take otherwise banned stimulants.

A total of 106 exemptions for banned drugs were given to major leaguers claiming attention deficit hyperactivity disorder from the end of the 2007 season until the end of the 2008 season, according to a report released Friday by the sport's independent drug-testing administrator.

That's up from 103 therapeutic-use exemptions for ADHD in 2007, according to figures cited by baseball officials before a U.S. congressional committee last year.

''This is incredible. This is quite spectacular. There seems to be an epidemic of ADD in major league baseball,'' said Dr. Gary Wadler, chairman of the committee that determines the banned-substances list for the World Anti-Doping Agency.

He recommended an independent panel be established to review the exemption requests.

''I've been in private practice for a lot of years. I can count on one hand the number of individuals that have ADD,'' he said. ''To say that close to 10 per cent of major league baseball players have attention deficit disorder is crying out of an explanation. It is to me as an internist so off the map of my own experience.''

Rob Manfred, baseball's executive vice president of labour relations, said it would be a mistake to compare ADHD in baseball with statistics for the general population.

''We are all male. We are far younger than the general population, and we have far better access to medical care than the general population,'' Manfred said.

The National Institute of Mental Health in Bethesda, Md., estimates that between three and five per cent of children have ADHD, according to its website.

Democratic congressman Henry Waxman of California, who chaired hearings into drug use in baseball, said he remained concerned about the large number of exemptions.

''But overall, I am pleased with the steps taken by MLB and the players' union to strengthen their drug testing program and eliminate the use of steroids and other performance-enhancing drugs,'' he added.

Players' union head Donald Fehr said all the exemptions went through approval by the program's independent administrator.

''All of the prescriptions for stimulants are the result of prescriptions written by doctors, and they also have to be passed on by Dr. Bryan Smith,'' Fehr said. ''I don't know what more there is to say about that.''

Baseball toughened its testing program after the 2007 season following recommendations by former Senate majority leader George Mitchell, who spent 1½ years investigating performance-enhancing drugs in baseball.

There were 1,348 players subject to testing last season, according to a baseball official who spoke to the Associated Press on condition of anonymity because the figure was not in the report. That was down slightly from 1,354 the previous year.

There were a total of 19 positives from 3,486 tests, according to the report.

There were 14 positives for banned stimulants and five players were suspended for using performance-enhancing drugs.

Pitchers J.C. Romero and Sergio Mitre were penalized this week after testing positive for androstenedione, which came from contaminated supplements they purchased over-the-counter.