Purpose-This study assessed the relationship between CNS treatment and psychologic mood using the Profile of Moods State (POMS), a standardized measure of affect, among a large sample of young adult survivors of childhood acute lymphoblastic leukemia (ALL; N = 555).Patients and Methods-Survivors of childhood ALL (ages 18 to 33 years at study entry) participated in a structured telephone interview eliciting demographic, health, and behavioral data and the POMS. Treatment data included total dose of CNS irradiation (CRT) and intrathecal methotrexate (MTX) obtained from medical records.Results-Mood disturbance was reported by 24% of survivors. High-dose CRT and MTX predicted disturbance rates modestly and primarily in combination with education variables. Interactions between educational achievement, a history of attendance in special education classes, and sex were better predictors than treatment type or dose. Non-white males, those younger than 12.5 years of age at diagnosis, and those with negative perceptions of current health and cancer's impact on employment were also at greater risk for mood disturbance (P < .01 to .001).Conclusion-Although most survivors are doing well psychologically, a subset of long-term survivors show potentially serious mood disturbance. Mood disturbance seems to be a function of interactions between preexisting individual difference variables (eg, sex, race/ethnicity), treatment factors, and posttreatment educational experiences. Prevention strategies aimed at childhood cancer survivors at greatest risk for mood disturbance may be improved by focus on posttreatment psychosocial and educational supports.RESEARCH ON survivors of childhood acute lymphoblastic leukemia (ALL) suggests that as expected survival time after treatment for ALL increases, the risk of neuropsychologic and psychosocial impairments in functioning may increase. 1,2 Although many survivors of Compared with other treatments, high-dose cranial radiation treatment (CRT) has been linked to lower intelligence quotient levels, 9 poor academic performance, 10 an increase in learning problems in school, 11 and a reduced likelihood of attending college as survivors become young adults. 12 Even low-dose CRT has been associated with mild delayed intelligence quotient decline, increased learning disabilities, and academic failure. 13-15 As concerns about the excessive toxicity of CNS radiation emerged, treatment protocols were shifted to include increasing doses of intrathecal (IT) methotrexate (MTX) chemotherapy and less CRT. These less toxic treatment protocols have sometimes 8,15 but not always resulted in reduced negative cognitive or psychologic outcomes. 16-18 Variation in dose of MTX and combinations of CNS radiation with MTX may be important factors in the equivocal data across studies.The relative benefit of MTX compared with CRT may also depend on demographic variables, such as age and sex. Treatment with CNS radiation at a young age may place survivors at greatest risk for neuropsychologic impairment. 2,13,14...