While research has tied optimism to better coping and disease course with health challenges such as surgery and AIDS, a new study is the first relating optimism to immune change in a healthy population. According to research to be published in the June issue of the American Psychological Association's (APA) Journal of Personality and Social Psychology, healthy first year law students who endorsed optimistic beliefs prior to the beginning of the school year had higher levels and function of key immune cells in the middle of their first semester.

Optimistic beliefs for the law students included positive evaluations of their abilities, expectations that they would succeed, and confident emotions when thinking about law school. In contrast, apprehension and uncertainty that they would succeed in law school reflected pessimism.

Psychologists Suzanne C. Segerstrom, Ph.D., Shelley E. Taylor, Ph.D., Margaret E. Kemeny, Ph.D., and John L. Fahey, Ph.D., of the University of California, Los Angeles examined whether optimism in the context of a stressor -- the first year of law school -- affected mood and immune changes in a sample of 90 law students (50 of whom had immune measures evaluated). The sample was 51 percent male, and the mean age of the sample was 23.9 years. The sample was 54 percent White, 15 percent Asian American, 11 percent African American, and 9 percent Hispanic.

While there were no immune differences between optimists and pessimists prior to beginning law school, those students who began the semester optimistic had more helper T cells and higher natural killer cell cytotoxicity mid-semester than students who had been pessimistic. Helper T cells are the "conductors" of the immune system, directing and amplifying immune responses. Natural killer cell cytotoxicity reflects the ability of these immune cells to kill cancer cells in the laboratory. Natural killer cells are thought to be important in immunity against viral infection and some types of cancers. The changes in the immune system are attributable to two psychological characteristics of optimists: they experience events as less stressful, and they show less negative mood, such as anxiety and depression.

"As evidence increases to show that psychological factors may play a role in the course of chronic diseases such as HIV infection, healthy people wonder if psychological factors also affect their health," says Dr. Segerstrom, lead author of the study and now on the faculty of the University of Kentucky. "We have seen that optimism positively affects the psychological response to stressful events, and this research reflects a first step toward expanding that observation to include physical health under stress."

The research adds to the growing number of studies that have helped scientists understand the contribution of psychosocial factors to physical health. Researchers previously found that optimism about health outcomes among HIV patients has been associated with slower immune decline and later symptom onset. However, the authors caution that more research is needed to establish whether these types of immune changes mean health benefits for people without chronic disease. "While this size of change in the immune system may not always translate into health differences, it does establish the possibility that people's outlook and mood when stressed might affect responses to common immune challenges such as exposure to cold viruses or immunization," says Dr. Segerstrom. This study shows that beliefs, such as optimism, and associated mood changes are important elements of the immune consequences of stressful events.

Reference: "Optimism is Associated With Mood, Coping, and Immune Change in Response to Stress"by Suzanne C. Segerstrom, Ph.D., Shelley E. Taylor, Ph.D., Margaret E. Kemeny, Ph.D., and John L. Fahey, Ph.D.; Journal of Personality and Social Psychology, Vol. 74, No. 6.

Suzanne Segerstrom, Ph.D. can be reached at 606-257-4549

06/26/98

The American Psychological Association (APA), in Washington, DC, is the largest scientific and professional organization representing psychology in the United States and is the world's largest association of psychologists. APA's membership includes more than 159,000 researchers, educators, clinicians, consultants and students. Through its divisions in 50 subfields of psychology and affiliations with 58 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting human welfare.