By Anne Brown
Producer, The Investigation
In World War I they called it shell shock, although it was often mistaken for cowardice and sometimes men suffering from it were shot "as an example" to their comrades.
Anxiety symptoms and stress have followed active service for many people through many conflicts, and left untreated they have fundamentally damaged the lives of countless ex-service men and women.
Today post traumatic stress disorder (PTSD) is a recognised condition suffered by many who have been on active service with the Armed Forces.
Post traumatic stress disorder is a recognised condition
The term is used to describe a range of psychological symptoms people may experience following a traumatic event, which is outside the normal human experience.
The atrocities witnessed during conflict, the fear and the killing, are outside normal human experience.
The men and women of the British armed forces have been in conflict somewhere almost continuously.
Since World War II they have seen active service in Malaya, the Falklands, the Gulf, the Balkans, Sierra Leone and of course, Northern Ireland, arguably the most difficult and dangerous of all.
Every one of these conflicts has resulted in psychiatric injury. And such damage may take years, even decades to come to the surface.
The intensity of the current conflicts in Iraq and Afghanistan is putting servicemen and women under heavier psychological pressure than ever before.
More than 100,000 British troops have been or are serving in Iraq. Already, more than 2,000 have sought help for psychological problems on their return.
With 15-20,000 more currently in Afghanistan, the numbers with PTSD or other mental health disabilities are likely to grow.
Ministry of Defence figures suggest that around 2% of all serving personnel will end up with these problems, and for the first time the MOD has admitted the numbers are growing.
The symptoms are common to almost all ex-service personnel who suffer from PTSD.
They include sleeplessness, flashbacks, nightmares, mood swings, intense uncontrollable anger and anxieties that colour every moment of their lives.
Sufferers may turn to alcohol or drugs; they may lose their families, who find themselves unable to cope with the unpredictability; they may become homeless; they may attempt suicide. The condition may last for a lifetime.
Symptoms include intense uncontrollable anger
Many have seen their friends and colleagues shot or blown up; many survived the same things themselves and suffer from survivor guilt; many have observed unspeakable outrages which they were powerless to prevent and many have been deeply traumatised by the act of killing.
While still in service many try to hide their symptoms, as any evidence of weakness or fragility is frowned on, but people may be treated in military hospitals.
Once discharged, their care is the responsibility of the NHS, which, under huge pressures coping with mental health issues itself, does not have the specific expertise needed to deal with ex-service personnel.
People coming back from Iraq are complaining that they're not fully supported by the government and can't get the help they need.
PTSD is treatable, although by the time many who need it actually get it, the condition has become deeply embedded.
Help and treatment are available through the service charities.
SSAFA, The Royal British Legion and Erskine can all point people in the right direction, and the Ex-Services Mental Welfare Society, also known as Combat Stress, only cares for those with psychological damage.
Treatment is partly funded by the government, but only if the veteran needing it has a war pension, with a certain percentage of that attributable to mental health.
For those without that, the cost is shared between themselves and the voluntary sector.
Many feel they are stigmatized both by the condition, and because they see themselves as charity cases.
As involvement in the current conflicts continue, the need for treatment can only continue to grow.
And the appointment of Derek Twigg, MP, as veterans minister, should lead to more being done for the men and women who have gone to war in our name.
The BBC Radio Scotland Investigation: Ex-Services Post Traumatic Stress Disorder on Monday 5 February at 0850 BST.