OTTAWA -- “I think you are screwing up.” Blunt words from a Canadian military hero, retired general Romeo Dallaire, to the Canadian government and Department of National Defence.

In a W5 exclusive, Dallaire announced that he is joining a lawsuit against the Canadian government and Defence Department over an anti-malaria drug that he, and other soldiers , were forced to take on missions to Rwanda, Somalia and Afghanistan.

Dallaire, who led the international peacekeeping mission in Rwanda in 1994, has become the highest ranking soldier to join an unprecedented legal action by veterans over the use of the anti-malaria drug Mefloquine. He joins nearly 900 other veterans who claim the Canadian government and Department of National Defence “willfully ignored and concealed the risks” of the drug, which is marketed under the brand name Lariam.

Dallaire has been hailed a hero, both for his attempts to stop the genocide in Rwanda, but also for his outspoken admission that he struggles with Post-Traumatic Stress Disorder. In the W5 documentary “The Guinea Pig Soldiers” (airing Saturday night at 7 p.m. on CTV), Dallaire said the drug Mefloquine made it difficult for him to do his job in Rwanda: “It was an impact that I considered serious enough that it was affecting my operational capability.” When the general requested he be taken off the drug, he was threatened: “They told me that if I did not continue to take Mefloquine, it would be perceived as a self-inflected wound. And I could be court-martialed.” That could have meant jail time for a Canadian general leading an international peacekeeping mission.

Veterans of missions to Somalia, Rwanda and Afghanistan allege that the drug has left them with long-term and debilitating side-effects that mimic PTSD but include tinnitus, memory loss, paranoia, extreme rage, suicidal ideation and rage. Lawyer Paul Miller, with the Toronto firm Howie, Sacks and Henry, is leading the legal action and says having Dallaire sign on is a game changer: "If a general is suffering from something like this, then the everyday soldier has confidence to know that they can join. There is credibility to the condition that they are suffering from.”

Watch the full W5 documentary 'The Guinea Pig Soldiers,' Saturday at 7 p.m. on CTV