The suicide rate among US soldiers has reached its highest level since records began almost 30 years ago, officials said.

Last year, 121 active members of the army took their own lives, up 20% on the previous year. Thirty-four of last year's deaths happened while the soldier was deployed in Iraq, compared to 27 in 2006.

Also on the rise are attempted suicides and self-harm. The number of soldiers who tried but failed to kill themselves or who deliberately injured themselves rose to 2,100 in 2007, up from 500 in 2002.

The Washington Post today reported on the case of Lieutenant Elizabeth Whiteside, who attempted suicide on Monday night by swallowing pills. She left a note saying: "I'm very disappointed with the army."

Whiteside had been awaiting news on a potential court martial for pulling a gun on a superior officer and then shooting herself after suffering a mental breakdown while working as a medic at an Iraqi prison.

She is now in stable condition, and the charges against her have been dropped.

The Post said studies had found that failed personal relationships, legal and financial problems and job-related stress have been the most common factors in soldiers' suicides.

With the army stretched thin by years of fighting two wars, the Pentagon last year extended normal tours of duty from 12 months to 15. Some troops have been sent back to the frontline several times.

Combat Stress, a British charity that provides care for veterans, said the most common mental illnesses it treats were depression, phobic disorders, obsessive compulsive disorder, substance abuse and post-traumatic stress disorder. It said many of the veterans it treats suffered from more than one of these conditions.