Dispositional optimism and stress-induced changes in immunity and negative mood

Area of Science:

• Psychoneuroimmunology
• Health Psychology
• Stress and Immunity

Background:

• Optimism's health benefits are known, but the underlying mechanisms, especially during stress, are unclear.
• Previous research indicated that psychological stress and immune stimuli can increase inflammation and negative mood.
• This study further analyzes data from a controlled experiment involving stress and vaccination.

Purpose of the Study:

• To investigate the relationship between dispositional optimism and stress-induced changes in immunity and mood.
• To determine if optimism modulates inflammatory responses (interleukin-6) to psychological stress.
• To examine optimism's effect on antibody production following vaccination under stress.

Main Methods:

• A double-blind, placebo-controlled study with 59 healthy men.
• Participants were randomly assigned to vaccine/placebo and rest/stress conditions.
• Assessed serum interleukin-6 levels, anti-Vi antibody titers, and mood states.

Main Results:

• Optimism was inversely related to interleukin-6 responses during stress, suggesting anti-inflammatory effects.
• Optimism was positively associated with antibody responses to the typhoid vaccine under stress, indicating enhanced adjuvant effects.
• Optimistic individuals reported less negative mood and reduced decline in mental vigor.

Conclusions:

• Optimism may promote health by counteracting stress-induced inflammation.
• Optimism can enhance the immune system's response to vaccination, particularly under stress.
• These findings highlight optimism as a potential factor in resilience to stress and illness.