Delayed sleep phase type sleep disorder is a circadian rhythm disorder that
results in symptoms of sleep-onset insomnia and difficulty awakening at a
desired time. Patients with delayed sleep phase-type sleep disorder can be
treated with chronotherapy, light therapy, vitamin B12, or melatonin.
Chronotherapy is a behavioral technique in which sleep time is systematically
delayed. Herein we report a 48-year-old woman that presented with delayed sleep
onset and describe chronotherapy as a treatment approach.