Moderator variables for the relationship between life change and disorders

Stress, externality, and depression

Previous research has found mixed support for the possibility that locus of control moderates the effects of life stress on depression. Two methodological choices may have influenced previous findings: the use of a unidimensional rather than a multidimensional locus of control scale, and reliance on linear statistical methods using median splits. We attempted to correct these choices by using the Levenson IPC scale (1974) and multiple regression analyses in a female undergraduate population (N = 158). The results supported use of a multidimensional scale, since Stress, Internality, and Powerful Others were found to have main effects on depression whereas Chance interacted with life stress. The question of whether locus of control refers to responsibility for causing an event, i.e., self-blame, or belief in control over future events, i.e., coping behavior, was discussed.

Weighted versus unweighted life event scores: is there a difference?

Life events researchers differ in their opinions as to whether weighted life event indices are more strongly associated with measures of pathology than a simple count of the number of experienced events. In the present review, it was found that across 18 studies the average correlation between weighted and unweighted totals was .94. In 16 of 19 studies, weighted scores did not improve the stress-illness correlation.

Life stress, personality and illness behavior: a prospective study

Six personality dimensions derived from a principal components analysis of the 16 PF were examined as possible modifiers of the impact of recent life changes on illness behavior in a prospective study of a student sample ( N = 136). Results indicated that undesirable life changes significantly predicted illness behavior while total life changes did not. None of the six personality dimensions proved to be significant predictors of illness behavior. The results did, however, indicate a significant interaction between the dimension of sensitivity and life stress, with low scorers on this dimension showing a strong tendency to react to life stress with increased illness behavior while high scorers did not. This finding is interpreted in terms of Sheldrake's hypothesis that more outer-directed persons would tend to suppress direct evidence of stress and therefore discharge stresses through forms of illness commonly regarded as non-stress-related.