Circadian rhythm sleep disorders affect the timing of sleep. (parentingscience.com)
Animals with gene mutations that significantly alter their circadian rhythms have shorter life spans, and circadian rhythm sleep disorders in humans can have profoundly negative effects, including increased risk for obesity, depression, cardiovascular disease and cancer. (scientificamerican.com)
If that's the trouble, you can proceed as if your child has a circadian rhythm sleep disorder (see next). (parentingscience.com)