OPTIMISM AND THE IMMUNE SYSTEM
By Suzanne Segerstrom, Ph.D., Shelley Taylor,
Margaret Kemeny, Ph.D., and John Fahey, Ph.D.
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
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
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
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
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.