The RSL is funding a training program to help doctors better recognise the hidden signs of post-traumatic stress disorder (PTSD) among Australian combat veterans.
It will be based on findings from the world's biggest study into Vietnam veterans, run by the Brisbane-based Gallipoli Medical Research Foundation.
It found returned soldiers who were eventually diagnosed with PTSD were twice as likely to suffer stomach ulcers and sleep apnoea, and four times more likely than the broader population to have a heart attack.
Foundation CEO Miriam Dwyer said the research gave them new insight into how PTSD often manifests with physical rather than emotional symptoms.
"Quite often it will be the GP they will go to with problems with their gastric health, problems with sleep and quite often what we do is treat symptoms rather than the underlying cause," she said.
"It's hoped it will help clinicians in what to look for, what cluster of symptoms, so this is another tool in the armour. What we want to do is educate our GPs to ask some probing questions."
Ms Dwyer said veterans have been slipping through the health net and the new training kit was aimed at changing that.
"The research gives us insight into how PTSD manifests itself as physical symptoms, which are vital clues when treating veterans who are reluctant to admit they have mental health issues."
More than triple the risk of acting out dreams while asleep
Twice the risk of sleep apnoea
Almost twice as likely to have restless legs
Increased daytime fatigue and sleepiness
Twice the chance of stomach ulcers
Double the chance of reflux
Constipation, diarrhoea and irritable bowel more likely
Fourfold risk of heart attack
Lower good cholesterol levels, increased risk of heart disease
RSL Queensland president Stewart Cameron said the clinical evidence now available would help doctors know what physical symptoms to look for in a sick veteran.
"The information out of the study I believe is a gold mine. It is saving lives and it is enriching and enhancing lives," he said.
"Our veterans deserve the very best prevention and treatment solutions we can provide."
Vietnam veteran Richard McLaren knows what it is like to suffer in silence. He was just 22 when he served in 9 Squadron RAAF as a helicopter crewman.
Nearly 30 years later he was diagnosed with PTSD.
"A psychiatrist basically told me to vegetate and go home and die. Nobody knew what to do with it or what the signs were, it was crazy," he said.
Years later, still suffering from depression and anxiety, he contemplated suicide.
"I got to the point where everything was too much. PTSD takes away a lot of your self-worth. I got to the point I thought my family would be better off without me," he said.
"I put a gun to my head but fortunately my faithful rescue dog Zou came where I was sitting and put his head on my knee. That stopped me pulling the trigger."
Mr McLaren, now 69, was one of the 300 veterans who took part in the Brisbane study.
He was also one of many found to be suffering from heart problems, sleep apnoea and an eating disorder.
He said while the new doctor's training kit might be too late for him, it would be a vital tool to help younger service veterans returned from conflicts in Iraq and Afghanistan to battle their demons.
"It means heaps to think no-one else will slip through the cracks. This program will be a huge help to them," he said.
"It is just getting that awareness and understanding of what can now be done."