Weekly, Canadian troops serving in Somalia were given heavy doses of mefloquine, a drug used to protect against malaria. Mefloquine is well known to have neurologic side-effects. The manufacturer's literature states that reactions are rare, but include convulsions, psychosis, nightmares, dizziness, headache, confusion, anxiety and depression.

Canadian medical personnel in Somalia reported that Canadian troops experienced these side-effects. The day the drug was administered was know as "psycho Tuesday". The Somali prisoner died on a Tuesday when the effects of the drug were at their peak. On top of that M. Cpl. Clayton Matchee had consumed several beers. The effects of alcohol consumption on mefloquine users is unknown.

"In my view," Cummins said, "that adds up to a reasonable doubt that M. Cpl. Clayton Matchee was capable of making the decision to kill Shidane Abukar Arone; reasonable doubt that he would have been found guilty of murder."

"Furthermore", Cummins noted, "Matchee's suicide attempt may have been mefloquine-related and Trooper Brown's judgement and that of other members of the Airborne may also have been clouded or distorted by the mefloquine."