Despite the growing accumulation of studies attesting to the association between life events and illness, either physical or mental, a number of critical methodological and conceptual issues are considered not to permit any clear answer to the basic questions regarding the importance of the role these events play in the etiology of such disorders. In an effort to address these issues, this study focuses on the overall level and types of disturbed behaviors shown by children who differ with respect to the life events which intervened between the original and follow-up interviews with their mothers in the course of a longitudinal study. Given this and the array of sociodemographic and familial variables on which the children have also been assessed and which permit examination and control for various competing hypotheses, the etiologic role of life events for psychological disorders is deemed to be determinable. The life events studied are limited to those outside of the child's and adolescents' control and/or independent of his psychiatric condition to prevent contamination between the two sets of variables. The stressfulness of life events are examined both in terms of change and undesirability-desirability. Groups clearly differentiated as to type and number of events are studied to ascertain the risks attached to exposure to different event types. (Author/JM)