High levels of post-traumatic stress among New Zealand's veterans have been exposed in new research by Otago University.
A survey of current and retired military personnel revealed a third had some symptoms of the condition.
It's described as a hidden cost of war. Military personnel returning home but keeping symptoms of post-traumatic stress hidden from family and friends.
"Being in operational service especially increases the risk of a traumatic event happening, such as seeing someone killed - which happened quite often in Vietnam - or being involved in a firefight," says Associate Professor David McBride, from the Otago University's department of preventive and social medicine.
More than 1800 veterans and current military personnel were surveyed by Otago University researchers.
A third of them had some symptoms of post-traumatic stress and one in ten are likely to be diagnosed with the disorder.
"The veterans with post-traumatic stress seem to be older and they were more often Māori," McBride says.
"But somehow, serving in the military longer helped to decrease the rates of post-traumatic stress."
Dunedin's RSA president Lox Kellas served in Vietnam. He says it took a long time for the serious symptoms to be recognised as a mental health condition, especially for those serving in the First and Second World Wars.
"It was often shellshock. And for some men, the consequences were fatal. They were shot. And nobody really understood what the medical consequences were," he says.
These days, there's a range of social support on offer for veterans but many are reluctant to use them.
"They dig into their gunpit basically and try to ignore things," Prof McBride says.
"But then things come to a head, and they reach a crisis point. And that crisis point is really bad."
He's encouraging veterans to open up to GPs and health professionals about their experiences which can help unmask the real reasons for issues like poor sleep or depression.