Last week the Pentagon released data that some 40,000 U.S. troops have been diagnosed by the military with post-traumatic stress disorder after serving in one or both of the conflicts in Afghanistan and Iraq from 2003 to 2007. The number of diagnoses jumped nearly 50 percent in 2007 over the previous year.

A couple of factors are at work. Troops are serving longer and in multiple deployments, during which they are exposed to horrific violence. Some of the increase may be due to better record-keeping on the part of the Pentagon, although some military officials say the numbers may be higher because the statistics do not include service members diagnosed by the Veterans Administration or civilian mental health providers. Worse yet, some service members may not be seeking care for fear of hurting their careers or because they will face a stigma for seeking mental health care.

The Pentagon must do more to encourage troops to seek care. Early and appropriate treatment can bring about substantial improvement in many patients with PTSD. Moreover, the military must strive to establish a culture that encourages service members to seek help without shame or fear of harming their careers.

For its part, the Pentagon is in the process of hiring 300 additional psychiatrists, psychologists and other mental health professionals to meet the growing demand for care. It also offers the "Battlemind" program to teach troops and family members what to expect before deployment and how to identify problems after a tour of duty.

Service members with PTSD can grow emotionally numb, which can cause their intimate relationships to suffer. Some troops with PTSD feel constantly under threat. They may relive the horror of being wounded in combat, or the deaths of their fellow soldiers in their nightmares, or intrusive thoughts.

Extraordinary demands have been made of the men and women serving in the Middle East. The buildup of troops in Iraq has required officials to increase tour lengths to 15 months. Reducing the tours to 12 months in the ongoing drawdown phase may lead to the added benefit of a reduction in stress and emotional and physical fatigue.

Because of the intense demands made of American service members and their families, the federal government must continue to seek ways to encourage service members to seek mental health treatment. The Pentagon must also better manage the lengths of troops' deployments to minimize the factors that can contribute to service members developing mental health problems.