People with asthma are more likely to have symptoms of depression. A new study suggests these symptoms are linked to a host of other negative health risks that may lead to a worsening of asthma symptoms and an overall decline in health.

"People who are depressed are more likely to ... have a harder time doing things that help maintain good health," said Aviva Goral of the Gertner Institute for Epidemiology and Health Policy Research in Israel, the corresponding author of a study appearing online in the journal General Hospital Psychiatry.

Results of Goral's study, which surveyed 9,509 Israeli adults, suggest that even mild depressive symptoms-with no accompanying diagnosis of clinical depression-may be associated with such health-related risk factors as smoking, physical inactivity and insufficient sleep. The findings are consistent with other studies that found that negative health-related risk factors lead to poor asthma control and may contribute to the link between asthma and depression.

Adequate sleep is vital to good health. Yet, Goral's study found that 56 percent of asthmatic people with depressive symptoms slept for 6 hours or less compared with 38 percent of people with asthma and no depressive symptoms. Asthma symptoms and certain asthma medications can be associated with poor sleep, which depressive symptoms may make even worse. Similarly, depressive symptoms were associated with a 70 percent increased likelihood of smoking. Smoking is associated with poor asthma control and worsening symptoms.

Carole Madeley RRT, CRE, MASc, director of respiratory health programs at the Ontario Lung Association, confirms that depression can lead to sub-optimal asthma self-management.

"Depression is more common in people with asthma than in the general public," she said, "and goes undiagnosed more often. It is associated with worse asthma-related quality of life and self-management. Asthma patients-especially those with severe asthma-should be assessed for depression, which should be treated as part of the overall asthma management."

Nonetheless, Madeley points out that research findings related to asthma and depression are not generally conclusive, and further studies are needed.