It's not just bullets and bombs that are threatening our soldiers in Iraq. The troops are battling another foe and it has felled more people than the fighting. Tom Hyland reports. OVERSEAS operations are taking their toll on an over-stretched Australian Defence Force, with mental illness rather than combat injuries emerging as the leading threat to soldiers. Figures obtained by The Sunday Age show that mental illness accounts for more than half the casualties suffered by Australian troops in Iraq. Over the past three years, 23 soldiers have been discharged from the army on mental health grounds due to their Iraq service. A further 29 who served in Iraq have also been discharged on mental health grounds not directly attributed to Iraq service. Instead, it was put down to other factors, including the possible cumulative impact of other deployments. Over the same period, 14 Australian soldiers have suffered physical combat injuries in Iraq, mostly from roadside bombs, according to the ADF's figures. An ADF spokeswoman was unable to give a breakdown on the extent of those injuries, but most are believed not to have been life-threatening or requiring repatriation to Australia. The ADF is unable to say how many soldiers who have served in Iraq have been treated for mental illnesses, including post-traumatic stress disorder (PTSD). While the discharges account for only a small percentage of the total number of personnel sent to Iraq — 7287 have served there since 2003 — the mental health of soldiers and veterans is emerging as an important focus for military health experts. What the ADF calls the "high tempo" of operations is prompting the focus on mental health, amid fears that regular overseas deployments are having a cumulative effect, leading to PTSD, depression and anxiety disorders. "Our ADF personnel face an increased tempo of operations and a diversity in the nature of operations," Veterans Affairs Minister Bruce Billson said. "This is a new situation of stressors to their emotional health and wellbeing." Mr Billson said the diverse operations — from combat, post-conflict stabilisation and peacekeeping, to disaster relief — were placing new strains on ADF members. Unlike older veterans of conventional military service, a new generation of veterans faced different and multiple "stressors", that could affect their psychological wellbeing.