THURSDAY, Jan. 6 (HealthDay News) -- Nursing home residents with serious mental illnesses are less likely to have advance care directives than those with no mental illness, researchers have found.

An advance care directive enables people to make informed decisions about their future treatment or identify a person who will make health care decisions for them if they become too ill to do so.

U.S. researchers looked at four types of advance care plans among 13,500 residents in 1,174 nursing homes: living wills; do-not-resuscitate orders; do-not-hospitalize orders; and restrictions on feeding tubes, medications or other treatments.

The study found that 68 percent of residents with no mental illness had at least one of the four types of advance care plans, compared to 57 percent of residents with a serious mental illness such as bipolar disorder or a psychotic disorder such as schizophrenia.

The study authors noted that mentally ill people in nursing homes are among the most important groups of patients with whom health providers should work to create advance directives.

"Our findings reflect disparities in medical decision-making caused by such factors as provider bias rather than actual differences in expressed care preferences," wrote the study authors, Dr. Peter Cram, Xueya Cai and Yue Li, who are affiliated with the University of Iowa and with Iowa City Veterans Affairs Medical Center.

The researchers also noted that nursing home care typically focuses on managing chronic medical conditions and functional disabilities. Staff members may not have been trained in mental health issues, they added.

The study is published in the January issue of the journal Psychiatric Services.

More information

The American Academy of Family Physicians has more about advance directives.