Melatonin Intervention For Neurocognitive Deficits in the St. Jude Lifetime Cohort

Primary objective: 1. To examine the efficacy of melatonin treatment on neurocognitive functioning in adult survivors of childhood cancer. Secondary objectives: 1. To evaluate the efficacy of melatonin treatment on delayed sleep onset latency in long-term childhood cancer survivors. 2. To investigate whether improvement in sleep onset latency due to melatonin treatment is associated with neurocognitive improvement in long-term childhood cancer survivors. This study is a randomized double-blind placebo controlled trial of time release melatonin for adult survivors of childhood cancer who demonstrate impaired neurocognitive functioning and/or difficulty falling asleep.