PORTLAND, Ore. (AP) -- Hospice patients who request physician-assisted suicide under a landmark Oregon law want control over their death and generally don't show signs of depression or worry that they could become a burden to their families, according to a survey of nurses and social workers.

The Oregon Death With Dignity Act was approved by voters in 1994 and went into effect three years later after voters overwhelmingly rejected an effort to repeal it and the U.S. Supreme Court ruled that states have the authority to pass laws regulating assisted suicide.

In a study published Thursday in the New England Journal of Medicine, Oregon researchers surveyed 306 nurses and 91 social workers who have treated hospice patients since 1997.

Nearly half -- 45 percent -- said they had cared for a terminally ill patient who had requested a lethal prescription, and 30 percent had cared for a patient who received one.

Control over the timing and manner of death was repeatedly the most important reason that dying patients cited for their request, while depression was rated the least important by hospice workers, said Dr. Linda Ganzini, an Oregon Health & Science University psychiatry professor who led the study.

"It's surprising how we found so little variation with regard to this characteristic, almost as if the nurses and social workers were all seeing the same patient," Ganzini said.

The study also suggests that lack of social support or fear of being a financial drain on family members are the least important factors in the decision to request assisted suicide, contrary to the criticism from opponents of the law, Ganzini said.

Supporters of the law say the study is further evidence it is working well and limited only to terminally ill patients who at least want the option.

"It should quiet the fears of people who believe that choice at the end of life is bad for patients or bad for medical care," said Barbara Coombs Lee, who heads Compassion in Dying and helped draft the Oregon law.

The survey was conducted in 2001, when the Oregon Health Division had recorded that 91 people had died by assisted suicide since the law went into effect late in 1997.

A questionnaire was mailed to 545 hospice nurses and social workers at all 50 Medicare-certified hospices in Oregon, and 397 workers responded.

There were 82 terminally ill patients at the hospices who requested lethal prescriptions, evenly divided between men and women with a mean age of 63.6 years. Eighty-three percent had cancer.

Dr. Susan Tolle, director of the Center for Ethics in Health Care at Oregon Health & Science University, said the study may reflect some bias by hospice workers who may be less opposed to assisted suicide.

The survey found 59 percent of the nurses and social workers supported the Oregon law, 26 percent opposed it, and 14 percent said they were neutral.

Ryan Ross, spokesman for the Denver-based Hemlock Society, said the survey shows the law works.

"All of the fears about what could happen if physician-assisted suicide was legalized have not happened," Ross said. "We can approach the end of life without undercutting the social fabric or pressuring people into doing what they don't want to do."

Copyright 2002 The Associated Press. All rights reserved.