Do you have trouble falling asleep, or keep to a schedule different from other people you know? It’s possible you’re suffering from Delayed Sleep Phase Disorder, or DSPD. The culprit: A delayed sleep cycle, in which your circadian rhythm drifts later than normal.

If you think this might be you, and your night owl ways are interfering with the rest of your life, consult a sleep specialist! Treatments for DSPD include chronotherapy—going to bed later and later every day until your sleep schedule normalizes; bright light therapy; and melatonin.

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