A Canadian Armed Forces soldier who was denied a promotion because his post-traumatic stress disorder prevented him from completing a required course should have his case re-evaluated to reflect the military's greater understanding of the condition, a federal court has ruled.

Cpl. Joel Mousseau turned to the court to challenge what he called his "unwarranted demotion" from the rank of master corporal, which he held on an acting basis for four years before his condition led to his medical release from the military.

Several military bodies had previously upheld the decision and refused to waive a training requirement that would have forced Mousseau to take the Armoured Crew Command course.

In its decision, the federal court said the course had to do with armoured vehicles and explosives "which was directly related to the PTSD diagnosis."

"It seems a bit of a 'Catch 22' to say that the soldier on (medical employment limitations) for PTSD must be exposed to the very thing that is a trigger to the PTSD though he had been doing an exemplary job of teaching other soldiers without the artillery course," the court said.

"It is understood that the understanding of PTSD within our Armed Forces has progressed rapidly lately. In fairness to the decision maker the evidence and procedures for dealing with PTSD that can now be marshalled may not have been available or before them at the time."

Mousseau joined the Armed Forces in 2001 and served two tours in Afghanistan, the last of which ended in 2008, according to court documents. After his return, he was stationed at CFB Wainwright in Alberta and appointed in 2010 to the rank of acting master corporal. 

He was then transferred to the joint personnel support unit in Edmonton in 2012 as a result of his condition and a year later, a medical officer recommended Mousseau be assigned a permanent medical designation, the documents say. 

A few months later, Mousseau was told he would have to give up his acting rank before retiring because he had not completed the required course.

The revocation was made official in the summer of 2014 and upheld by several military reviews, including one by the Chief of the Defence Staff, who has direct responsibility for the command, control and administration of the Canadian Forces.

The Chief of Defence Staff refused to use his discretionary power to waive the requirement and award Mousseau the rank of master corporal, agreeing with an earlier decision that Mousseau had been treated fairly.

The court disagreed that Mousseau had been given fair consideration for his condition.

"It was an unreasonable decision given the evidence of his particular situation and the lack of transparency of why he was not treated the same as others in similar situations that were retired without the course or reversion of the rank," the court said.

Mousseau has been granted a judicial review but the court said it could not award him damages or a reinstatement of rank.

Paola Loriggio, The Canadian Press

Note to readers: This is a corrected story. An earlier version referred to Cpl. Joel Mousseau as an officer