Homosexuality is still a mental disorder, according to the Pentagon.

Research by the Centre for the Study of Sexual Minorities in the Military at the University of California discovered a document from the Department of Defence which listed homosexuality alongside mental problems, despite it being declassified as a condition by the American Psychological Association (APA) in 1973.

Several Congress members have sent a letter to Secretary of Defence Donald Rumsfeld asking him to review the Pentagon Instruction which was written in 1996 and re certified in 2003.

The letter, which was signed by nine members of the House Armed Services Committee led by Representative Marty Meehan of Massachusetts, asks the department to update the classification.

The letter notes that the American Psychiatric Association (APA) removed homosexuality from its list of mental illnesses over thirty years ago, and affirmed that homosexuality “implies no impairment in judgment, stability, reliability, or general social and vocational capabilities.”

Last week, the APA, which authors the DSM-IV-TR, the definitive volume on mental health classification, wrote its own letter to the Pentagon urging it to remove homosexuality from the list and update it to reflect the current consensus of medical professionals.

Edwin Dorn, the former Under Secretary of Defence who signed the original Instruction, agreed the document might be out of date. “It is certainly time to revisit the issue of whether homosexuality should be considered a mental disorder.

The revelation supports other work by the CSSMM which researched the military’s treatment of gay and lesbian recruits.

It gave fails in four out of five areas including the mental health classification, as well as anti-gay harassment and command climate, evidence-based assessment of ‘Don’t Ask, Don’t Tell, and family support, and it scored a D in suicide prevention.

Dr. Steven Samuels, a social psychologist and professor of leadership who has worked extensively with the military, said it was clear that the misclassification was not scientifically derived and suggested it might be socially or politically motivated. “The very few psychologists who have used this type of abnormal pseudo-classification tend to be motivated by dogma rather than scientific data,” he said.

“To classify homosexuality with mental retardation, impulse control, and substance abuse, shows at best an ignorance of basic psychology and at worst a purposeful intolerance and discriminatory practice that is incompatible with the high values of the military.”

Dr Aaron Belkin, director of CSSMM, expressed grave concern that the military continues to list homosexuality as a mental illness. “It’s unclear why a DoD document would classify homosexuality as a mental disorder over thirty years after the psychiatric community acknowledged this is a mistake,” said Dr Belkin.

He described new research showing that military psychologists and chaplains lack the training needed to monitor and treat the mental health of gay and lesbian soldiers. These professionals “may be hampered by confusing and conflicting [DoD] recommendations” in treating the mental health needs of gays and lesbians,” according to research recently published in the journal, Professional Psychology, which also noted that some military chaplains practice “reparative therapy” on gay troops.

“This is exactly what you’d expect would happen when an institution is so out of touch with evidence about mental health,” Dr Belkin said. “This misclassification reflects an orientation of neglect regarding gays in the military that’s hurting our troops and our straining our mission.”

The Pentagon currently operates a Don’t Ask Don’t Tell policy in the military which effectively bans openly gay or lesbian recruits from serving.