Army Spc. Jeffrey Henthorn, 25, of Choctaw, Okla., was sent back to Iraq for a second tour even though his superiors knew he had twice threatened suicide. He killed himself in 2005.

Army Pfc. David L. Potter, 22, of Johnson City, Tenn., was diagnosed with anxiety and depression while serving in Iraq in 2004. Records show Potter remained on active duty in Baghdad despite a suicide attempt and a psychiatrist's recommendation that he be separated from the Army. Ten days after the recommendation was signed, he slid a gun out from under another soldier's bed and shot himself.

These deaths are among the most extreme failures by the U.S. military to properly screen, treat and evacuate mentally unfit troops, a Hartford Courant investigation has found.

Pressed by troop shortages, the military has increasingly sent, kept and recycled troubled service members into combat — practices that undercut past assurances it would improve mental-health care. Besides suicides, experts say gaps in such care can fuel violence between soldiers, accidents and critical mistakes in judgment during combat operations.

Among the newspaper's findings:

Despite a congressional order that the military assess the mental health of all deploying troops, fewer than one in 300 service members see a mental health professional before shipping out.

Once at war, some unstable troops are kept on potent antidepressants and anti-anxiety drugs with little or no counseling or medical monitoring, in violation of the military's own regulations.

And some troops who developed posttraumatic stress disorder, or PTSD, after serving in Iraq are being sent back to the war zone, increasing risk to their mental health.

These practices helped fuel an increase in the suicide rate among troops serving in Iraq, which reached an all-time high in 2005 when 22 soldiers killed themselves — accounting for nearly one in five of all noncombat Army deaths.

The spike in suicides is a setback for military officials, who had pledged to Congress in late 2003 to improve mental health services after a spate of suicides in Iraq during the first seven months of the war. When the suicide rate improved in 2004, top Army officials had credited their renewed prevention efforts.

The Courant investigation found that at least 11 service members who committed suicide in Iraq in 2004 and 2005 were kept on duty despite exhibiting signs of significant psychological distress.

The newspaper obtained records under the federal Freedom of Information Act, including never-before-released pre-deployment screening data for thousands of troops and investigative reports into dozens of service members' deaths. It interviewed more than 100 mental health experts, service members, family members and friends. While the military does not publicly identify suicide cases, The Courant was able to identify — in most cases for the first time — the service members who killed themselves in Iraq.

The Army's top mental health expert, Col. Elspeth Ritchie, acknowledged that some deployment practices, such as sending service members diagnosed with PTSD back into combat, have been driven in part by a troop shortage.

"The challenge for us ... is that the Army has a mission to fight. And, as you know, recruiting has been a challenge," she said. "And so we have to weigh the needs of the Army, the needs of the mission, with the soldiers' personal needs."

But troubled troops often get lost in that balance.

Under the military's predeployment screening process, troops with serious mental disorders are not being identified — and others whose mental illnesses are known are being deployed anyway.

A law passed in 1997 requires the military to conduct an "assessment of mental health" on all deploying service members. But the only "assessment" is a single, self-reported mental health question on a predeployment form filled out by service members.

Even using that limited tool, troops who self-report psychological problems are rarely referred for evaluations by mental health professionals, Department of Defense records show. From March 2003 to October 2005, only 6.5 percent of deploying service members who indicated a mental health problem were referred for evaluations; overall, fewer than one in 300, or 0.3 percent, of deploying troops were referred for such screenings.

That rate is dramatically lower than the more than 9 percent of deploying troops that the Army acknowledges in studies have serious psychiatric disorders.

Military investigative reports and interviews with family members also show that some service members who committed suicide in 2004 and 2005 were kept on duty despite clear signs of mental distress, sometimes after being prescribed antidepressants with little or no mental health counseling or monitoring. Those findings conflict with regulations adopted last year by the Army that caution against the use of antidepressants for "extended deployments."

The use of psychiatric drugs has alarmed some medical experts and ethicists, who say the medications cannot be properly monitored in a war zone.

"I can't imagine something more irresponsible than putting a soldier suffering from stress on (antidepressants), when you know these drugs can cause people to become suicidal and homicidal," said Vera Sharav, president of the Alliance for Human Research Protection. "You're creating chemically activated time bombs."