For older men, feelings of depression may weaken the immune system, new research suggests. And anger seems to have a similar effect in both men and women caring for a spouse with Alzheimer's disease.

People have traditionally looked at depression and stress with a one-size-fits-all mentality. This view suggests that all stressors will apply equally to all people. But there are certain groups, such as older men and caregivers, who are more vulnerable to stress and depression.

The researchers studied the relationship between anger, depressed feelings and the immune system in 82 elderly individuals who cared for a spouse with Alzheimer's disease. Caregivers were compared with a "control" group of 83 married noncaregivers who were matched for age and sex.

At the start of the study and 18 months later, the investigators evaluated the participants' physical and psychological health, as well as their physical activity. Investigators also measured how vigorously participants' immune systems responded to substances that trigger the activation of cells called lymphocytes.

In men, feelings of depression were linked to a diminished immune response. Most of the depressed feelings of men in the study arose not from actual clinical depression but from feelings of loneliness, the report indicates. Older men may be more reluctant to talk about their problems and tend to have fewer friends than older women.

Caregiving is not a traditional male role, which may affect how men cope with this responsibility. Some research has suggested that men's bodies are better equipped for dealing with short-term challenges than long-term challenges.

Men typically experience bursts of stress hormones when faced with a challenge, but this type of response may not be effective for dealing with chronic sources of stress, such as caregiving.

Although the relationship between depressed mood and immunity differed by gender, higher levels of anger were linked to reduced immune function at the end of the study in both male and female caregivers.

The combination of anger and chronic stress can result in reduced immune function.

Journal of Behavioral Medicine 2001;24:537-555