Tourette’s syndrome (TS) and early-onset obsessive-compulsive disorder (OCD) are etiologically related, chronic familial neuropsychiatric disorders of childhood onset characterized by a wide array of intrusive sensory urges, motor and vocal tics, recurrent thoughts and impulses, and negative behavior. Both TS and OCD are widely accepted as stress-responsive disorders with increases in symptoms occurring at times of stress. This longitudinal study considered the optimal method for the assessment of psychosocial stress in TS and early-onset OCD and described the development of a new, standardized, investigator-based interview, the Yale Children’s Global Stress Index (YCGSI), for the assessment of stressful life events causing psychiatric disorders in childhood and adolescence. The study presented data concerning the development and reliability of YCGSI to measure the global impact of major life events reported over set time periods. It then examined the convergent and divergent validity of these ratings by comparing them with various other self-report and parent-report measures of stress and other related constructs. This was followed by a test of the validity in the utility of the YCGSI, the null hypothesis that TS and early-onset OCD patients experience no higher levels of psychosocial stress compared with unaffected control subjects. Lastly, a series of exploratory analyses were performed to determine whether any of the stress measures were correlated. Thirty-three children, aged 7-17 with either a chronic tic disorder, OCD, or both, as well as 25 unaffected control children without these disorders were assessed at baseline and 4-months later. Daily life stressors were found to be related to tic and OC symptom severity. The findings suggest that children and adolescents with TS and early-onset OCD experience a higher number of daily stressful events and major life stressors. Results showed that YCGSI demonstrated reasonable psychometric properties of interrater reliability and convergent validity. The YCGSI may be useful in longitudinal studies examining stress and immunological status with future studies suggested in evaluating the utility of the YCGSI for the assessment of stress as it relates to possible autoimmune changes. References