An American Olympic judo contender, Nick Delpopolo, was expelled from the London 2012 Olympic Games Monday after he tested positive for marijuana, and that has some experts raising questions about whether it makes sense to include marijuana on the World Anti-Doping Agency's (WADA) list of banned substances.

[image:1 align:left caption:true]Delpopolo said he had inadvertently consumed marijuana in a food item he did not know contained it.

Concerns about athletes "cheating" by using performance enhancing drugs is one thing, but the use of recreational drugs that do not enhance -- and could well detract from -- competitive performance is another. Recreational drugs are banned not because they might provide an athlete with an unfair advantage, but because their use by athletes can cause public relations problems for organized sports, which like to tout athletes as role models for youth.

But some experts told Reuters Monday that sports' PR concerns were no reason to ban athletes for using marijuana. They also suggested the time, expense, and effort of drug testing athletes might be better spent going after real cheats who do blood doping with EPO or use anabolic steroids to increase muscle growth and testosterone levels.

"There's no evidence cannabis is ever performance enhancing in sport, and since its use is legal in a number of countries, there's no reason for it to be banned by WADA," said David Nutt, a professor of neuropsychopharmacology at Imperial College London. "I can't think of any sport in which it would be an advantage. And it seems ludicrous that someone could quite legally smoke cannabis in Amsterdam in the morning and then come over to London in the afternoon and be banned from competing."

But marijuana is banned by WADA, and that means athletes caught using it during a competition face a two-year ban. Still, unlike performance enhancing drugs, WADA does not punish athletes who test positive for pot outside of competitions. That stance has led some scientists to suggest that WADA's reason for banning marijuana is political, not scientific.

"The problem is the elite athletes should be seen as role models for young kids, and so they ban cannabis because they don't want to have the image of gold medalists smoking joints," said one British-based sports scientist who asked not to be identified because of the sensitivity of the issue.

[Ed: If officials don't link images of athletes smoking marijuana, they might have a poor strategy -- no one knew Delpolo used it, before he was sanctioned, but now everyone does.]

"It's hard to imagine how smoking a joint or eating marijuana brownies is going to help somebody in judo," said Michael Joyner, a member of the Physiological Society and a researcher at the Mayo Clinic in Minnesota in the United States. "My advice to WADA is that they should focus on drugs that are clearly performance enhancing in the sports where they are clearly performance enhancing."

According to WADA, substance merit inclusion on its banned substances list if they meet two of these three criteria: they are proven to be performance enhancing, they are dangerous to the health of athletes, or they are contrary to the spirit of sport. There is little or no evidence that marijuana can enhance sporting performance, while there is evidence it could have a negative impact. It can slow reaction times, cause coordination problems, and reduce hand-eye coordination, none of which is going to increase an athlete's chances of victory.

While marijuana is not harm free, there is little evidence it is dangerous to the health of athletes. Nor is it clear why marijuana use would be "contrary to the spirit of sport."

WADA isn't keen to clarify. It refused to comment Monday on a Reuters query about why marijuana is banned.