The question of whether Australia does enough to support its ex-service personnel is growing in urgency, with Labor leader Anthony Albanese this week adding his voice to those calling for a royal commission into veteran suicides.

The numbers are alarming – between 2001 and 2017, 419 serving and ex-serving Australian Defence Force personnel died by suicide. But while the suicide rate for men still serving was 48% lower than in the equivalent general population, the rate is 18% higher for those who had left the military.

For women it’s a similar story, where the suicide rate for ex-serving women is higher than Australian women generally. However, the small numbers of ex-service women who have been studied means the data are limited.

But there’s another issue afflicting ex-military men that’s not often discussed: they are imprisoned twice as often as men in the general Australian population. This is according to the first known Australian prison audit to identify incarcerated ex-service members, conducted in South Australia last year.

In fact, these findings support research from England, which identifies ex-service men as the largest incarcerated occupational group.

Read more: Enough inquiries that go nowhere – it's time for a royal commission into veteran suicide

The high rate of imprisonment, along with the spike in the suicide rate of ex-members, reflects the challenges some service people face transitioning from military service back to civilian life, and the critical lack of available transition planning and support.

Why do some veterans turn to crime?

When a United States ex-Marine fatally shot 12 people in California in 2018, President Donald Trump promoted a widespread, oversimplified connection between military service and criminal offending. He said the shooter

was in the war. He saw some pretty bad things […] they come back, they’re never the same.

We have so far interviewed 13 former service men for our ongoing research, trying to explain the findings of the South Australia audit. And we found the connection between military service and criminal offending is more complex than Trump suggests.

Read more: Veterans have poorer mental health than Australians overall. We could be serving them better

The combination of childhood trauma, military training, social exclusion and mental health issues on discharge created the perfect cocktail of risk factors leading to crime.

For many, joining the service was a way to find respect, discipline and camaraderie. In fact, most interviewees found military service effective at controlling the effects of childhood trauma. One man we interviewed said he

could see me life going to the shit, that’s when I went and signed up for the army […] The discipline appealed to me. To me I was like yearning for it because I was going down the bad road real quick.

Another explained that joining the military was the

BEST thing I ever did. LOVED it. Well they gave me discipline, they showed me true friendships and it let me work my issues out […] I loved putting my uniform on and the respect that I could show other people, whereas before I’d rather hit them.

Leaving the military can aggravate past trauma

However, all men complained military discharge was a complete, “sudden cut”. This sudden departure from the service, combined with the rigorous military training, can aggravate previous trauma. As one ex-service member put it:

the military is a fantastic thing […] but the moment that you’re not there […] it magnifies everything else and it’s just like a ticking time bomb. I mean you’re trained to shoot people.

Another reflected that when he left the army, he lost the routine that kept his past traumas at bay.

I was working myself to the bone just to stop thinking about it. Then when I got out issues were coming back, coming back. I’ve lost my structure […] and life just went to crap.

AAP Image/Mick Tsikas

Every man we interviewed had been diagnosed with some combination of post traumatic stress, multiple personality disorder, anti-social personality disorder, bipolar, depression, panic disorder, obsessive compulsive disorder or alcohol and other drug dependence.

They arose from various combinations of pre-service and service-related trauma.

All interviewees lacked support from the Australian Defence Force or government veteran services. One explained how he found it difficult to manage post traumatic stress since his usual strategies were “getting very thin”.

Read more: From shell shock to PTSD: proof of war's traumatic history

And the lack of support for their mental health issues worsened when they were incarcerated because they said the Department of Veterans Affairs cut ties, and “no-one inside the prison system is going to pay for psychological help”.

Maintaining identity

For some men, joining criminal organisations was a deliberate way to find a sense of belonging and the “brotherhood” they missed from the defence force. One man reflected:

I found a lot of Australian soldiers that are lost. You think you’re a civilian but you’re not, you never will be […] even three years’ service in the army will change you forever. And the Australian government doesn’t do enough.

Ex-service men in prison are a significant, vulnerable part of that community. The Australian Defence Force and government veteran agencies need to urgently reform transition support services because current discharge processes are costing lives.

Read more: 5,800 defence veterans homeless in Australia – that's more than we thought

English research has found peer support helps service men transition into civilian life, but the men we interviewed did not receive peer support until they were in prison.

Then, it was through a welfare organisation and Correctional Services, not defence agencies.

One man told us that after his discharge

I actually went back and asked if I could mow the lawns for free, just so I could be around them still. They wouldn’t allow it.

If ex-service men could maintain contact with the Australian Defence Force through peer support and informal networks, their identity and sense of purpose could be maintained to reduce the risk factors for offending and re-offending.

If you or anyone you know needs help or is having suicidal thoughts, contact Lifeline on 131 114 or beyondblue on 1300 22 46 36.