WASHINGTON - U.S. troop morale improved in Iraq last year, but soldiers fighting in Afghanistan suffered more depression as violence there worsened, an Army mental health report says.

And in a recurring theme for a force strained by its seventh year at war, the annual battlefield study found once again that soldiers on their third and fourth tours of duty had sharply greater rates of mental health problems than those on their first or second deployments, according to several officials familiar with the report.

All spoke on condition of anonymity to describe the findings ahead of the study's release Thursday.

The report was drawn from the work of a team of mental health experts who traveled to the wars last fall and surveyed more than 2,200 soldiers in Iraq and nearly 900 in Afghanistan. In the fifth such effort, the team also gathered information from more than 400 medical professionals, chaplains, psychiatrists, psychologists and other mental health workers serving with the troops.

Officials said they found rates of mental health problems such as anxiety, depression and post-combat stress were similar to those found the previous year in Iraq, when nearly 30 percent of troops on repeat tours said they suffered a problem.

It was unclear how the new data might relate to a recent report showing that as many as 121 Army soldiers committed suicide in 2007, an increase of about 20 percent over the year before. The preliminary figures released in January said that there were 89 confirmed suicides last year and 32 deaths that were suspected suicides and still under investigation.

"Although we have had many successes, there are also areas of concern," Lt. Gen. Eric B. Schoomaker, the Army surgeon general, said in testimony prepared for a congressional committee hearing.

Soldiers in Afghanistan had rates of mental health problems similar to those in Iraq in 2007 with the exception of depression, officials said the new study showed. The percentage reporting depression in Afghanistan was higher than that in Iraq, and mental health problems in general were higher than they had previously been in Afghanistan. They gave no statistics, but a 2004 study conducted in the states with troops before and after they deployed to Afghanistan found that roughly one in 10 developed a mental health problem requiring treatment.

Though U.S. troops suffered their highest level of casualties in both campaigns last year, that came as violence was decreasing in the five-year-old Iraq conflict and increasing in Afghanistan, now in its seventh year.

Troops' mental health problems are linked directly to the amount of exposure they have to combat, and officials said that last year the level of violence was more pronounced in some places of Afghanistan than it was in Iraq. Some 83 percent of soldiers in Afghanistan reported being exposed to mortar fire and similar action as fighting heated up against Taliban and al-Qaida fighters, compared with 72 percent in Iraq, according to the study.

Having troops spread out and more isolated over the rugged terrain in a less developed Afghanistan made it necessary at times to bring soldiers in by helicopter when they needed mental health care, one official said. After the survey was taken, mental health professionals were dispersed more to put them nearer to the forces they serve, he said.

Officials said other findings included:

_Soldiers who underwent special "Battlemind" training reported fewer problems than those who did not. The program teaches troops and families what to expect before soldiers leave for the wars and what common problems to look for when readjusting to home life after deployment.

_Progress was made toward reducing the fear and embarrassment that keeps soldiers from asking for help with mental health problems. In 2007, 29 percent of those surveyed in Iraq said they feared seeking treatment would hurt their careers, down from 34 percent the previous year.

_Eleven percent of those polled in Iraq said their unit's morale was high or very high, compared with 7 percent the previous year. Individual morale was reported high or very high among 20 percent, compared with 18 percent the previous year.

Sending mental health advisory teams to do extensive surveys and focus groups in the combat theater of operations was a groundbreaking effort when started in 2003, the year the U.S. invaded Iraq. The goal is to assess how troops are doing at the warfront and how well behavioral health services provided by the military are working for the force.

Extensive reports have been produced after each survey and they have led directly to changes in the way services are delivered in the combat theater.

Among changes considered this year is whether more mental health workers might be needed at the war front. Since all troops there over the past year have been serving extended 15-month tours instead of 12 - and a larger number were there for repeat tours - officials questioned whether the ratio of mental health workers-to-troops that was appropriate in 2003 and 2004 is appropriate now, Col. Elspeth Ritchie, psychiatry consultant to Schoomaker, told a recent news conference.

The number deployed to Iraq has been pretty much consistent throughout the war - averaging about 200 psychiatrists, psychologists, social workers, psychiatric nurses and technicians, Ritchie said.