The growing number of veterans from Iraq and Afghanistan facing mental disorders represents a "national crisis," said Elizabeth Clark, head of the National Association of Social Workers, one of four organizations promising to assist the Give an Hour charity.
The American Association of Pastoral Counselors, American Psychiatric Association and American Psychological Association also threw their weight behind the non-profit, which seeks to enlist an army of volunteers to provide free mental health services to US troops and their families.
"The backing of these four organizations opens the door to roughly 400,000 mental health professionals," Give an Hour spokeswoman Lauren Itzkowitz told AFP.
The group, founded three years ago by clinical psychologist Barbara Romberg, wants to expand its current list of around 3,000 volunteers to 40,000.
Of the 1.7 million soldiers who have served in Iraq and Afghanistan, around 300,000 suffer from post traumatic stress disorder or major depression and a slightly greater number experienced "probable" traumatic brain injury, a study released in April by the RAND Corporation estimated.
The cost of treating soldiers diagnosed with PTSD or depression in the first two years following their return from war was estimated by RAND to be up to 6.2 billion dollars, while the cost of one year of treatment for just 2,700 cases of traumatic brain injury identified to date was up to 910 million dollars.
When the RAND report was compiled, only around half of veterans had sought help for these "invisible" mental wounds of war on their return to the United States.
Much of the burden of helping US combat veterans and their families to cope with psychological problems has been carried by the military and the Department of Veterans Affairs.