The effect of daily Hassles of humoral immunity: an interaction moderated by locus of control.

Research has shown that stress is associated with depressed cellular immune functioning. Controversy exists as to whether humoral immunity shows a similar depression under stress. Several psychological variables have been found to moderate responses to stress. In particular, an internal locus of control has been correlated with better health. The present study examined the level of salivary immunoglobulin A (IgA) and health locus of control in subjects with high and low stress levels. The Hassles scale was administered to identify two subject groups differing significantly in reported stress levels. Results showed no significant differences between the two groups on salivary IgA. There was a significant negative correlation between IgA and internal locus of control. The direction of this correlation is in contrast with previous findings on internality. The evidence suggests that high internal individuals may be especially vulnerable to high levels of stress, particularly stress that they cannot control. Also, there was a significant difference in IgA levels between females depending on whether they were in the first or the second half of their menstrual cycle. Those in the premenstrual phase had lower IgA levels.