By Andrew Buncombe in Washington Published: 19 April 2007
It has been more than 35 years since Daniel Seidenberg was seriously wounded in Vietnam, but barely a day goes by without something happening that triggers an anxiety attack deep inside him.
"For instance, if someone runs across my line of vision very fast, I immediately go on alert," he said, speaking from Santa Barbara, California. "There are thousands of little triggers - the sound of an explosion, a car back-firing."
Countless thousands of military veterans are suffering from post traumatic stress disorder (PTSD) - a phenomenon campaigners say receives too little attention and too few resources. But researchers in the US are developing a controversial new treatment that could potentially help by reducing the intensity of a particular traumatic memory. They stress they are not trying to wipe out the memory itself, but rather to alter a patient's response to it.
"We're optimistic about the theoretical potential, but the data are very preliminary. This is far from a sure thing," said Dr Roger Pitman, a Harvard Medical School psychiatrist who has been carrying out research on trauma victims at Boston's Massachusetts General Hospital.
Researchers have been investigating how the brain stores memories, and they have discovered that some drugs have the potential to interrupt the process - not just if taken in the immediate aftermath of an event, but even years later. One of the drugs they have used is Propranolol, originally developed to treat high blood pressure and which affects the hormone adrenaline.
Researches believe adrenaline affects the ways memories are retained, and that PTSD is the result of too much adrenaline entering the brain at the moment a traumatic event is being stored, or "consolidated". By working with a psychologist to talk a patient through the traumatic experience, and then using the drug, the hope is that memories can be reconsolidated.
Dr Pitman added: "We do not have the ability to 'wipe out' any memories in the usual sense. What we're trying to do is reduce the intensity of the conditioned fear response - how much the subject becomes upset when reminded of the traumatic event. In this experimental paradigm, the Propranolol is given after the reactivation of the traumatic memory, so it's this memory that we're trying to affect."
The treatment is not without controversy. "There are several major concerns [about these kinds of drugs],"Felicia Cohn, a medical ethicist at University of California, told ABC News. "Is the act of altering memories even an appropriate medical intervention?"
Nevertheless, some see the new treatment as having potential. Mr Seidenberg, 59, who spent four months in combat in Vietnam with the 199th Light Infantry Brigade, said he believed veterans had to be encouraged to work through their problems in "your gut, in your soul", rather than by taking drugs. But other veterans have said they would be keen to take the drug if it could help them.
How many troops returning from Iraq are suffering mental health issues is unclear. The Pentagon estimates it is one in eight, but others say the number could be much higher. Judith Broder, of The Soldiers Project, an organisation that provides free psychotherapy to veterans and their families, said: "PTSD, depression, suicide, hidden traumatic brain injuries, divorce and family disruption are all serious consequences that our vets are struggling with."
The consequences of not treating the problem are all too clear from the numbers of returning soldiers who have taken their own lives. In December 2005, after a tour in Iraq, Ellen and Randy Omvig's 22-year-old son committed suicide. They said: "Just a few months after returning from an 11-month tour in Iraq, our son Joshua took his own life. Like so many of the brave men and women who have fought in these wars, Josh was suffering from PTSD."