This Tourette Association of America-funded project examined circadian rhythms and sleep disturbance in adults with Tourette's disorder and adults free of psychiatric conditions, and piloted the effects of wearable short-wavelength morning light therapy in those with Tourette's disorder. Results showed subjective (i.e., morningness-eveningness) but not objective (i.e., dim light melatonin onset) delays in circadian timing, and greater sleep disturbance per both self-report and actigraphy in adults with TD relative to controls. Following a two-week course of morning light therapy, there were significant advances in circadian phase fi.e., dim light melatonin onset), but not self-reported chronotype. There were also significant reductions in tic severity and tic-related impairment, daytime sleepiness, and anxiety.