Optimism is associated with mood, coping, and immune change in response to stress.

This study explored prospectively the effects of dispositional and situational optimism on mood (N=90) and immune changes (N=50) among law students in their first semester of study. Optimism was associated with better mood, higher numbers of helper T cells, and higher natural killer cell cytotoxicity. Avoidance coping partially accounted for the relationship between optimism and mood. Among the immune parameters, mood partially accounted for the optimism-helper T cell relationship, and perceived stress partially accounted for the optimism-cytotoxicity relationship. Individual differences in expectancies, appraisals, and mood may be important in understanding psychological and immune responses to stress. (PsycINFO Database Record (c) 2011 APA, all rights reserved)