A reader asks:

Is it possible to have a rare case of extreme advance of sleep, which means you get tired, earlier and earlier in the day, but without depression? It is actually the opposite of delay phase. The condition was caused by seeing light at the wrong time of the day, causing a phase advance, repeated again and again, leading to a very bad situation–really early sleep onset morning/afternoon with insomnia at night. Do you have suggestions to correct this rare case?

Answer:

Yes, the advanced sleep phase disorder is opposite to the more prevalent delayed sleep phase disorder. This may be caused by inappropriate light exposure, a genetic predisposition for a fast internal circadian clock, or both. You indicate that before your repeated light exposure at the “wrong time of day” you did not experience the problem, so the cause appears to be environmental. Yet, it seems that the problem did not resolve after you eliminated the problematic lighting exposure. We would need to know much more about your abnormal sleep, and also your work schedule, to make a specific recommendation (which is beyond the scope of this forum).

However, we can offer some general hints. Using bright light therapy just before your daytime sleep episode (say, noontime), followed by restricted light exposure (strong wrap-around sunglasses) for the rest of the day after you wake up, should begin to move your internal clock later. As this happens, you can delay the light exposure accordingly, until you are going to sleep in the late evening (say, 10 p.m.). You can expedite the process by taking a low dose of melatonin (say, 3 mg) when you wake up in late afternoon or early evening. Be careful never to use melatonin when exposed to bright outdoor or indoor light. Caveat: If you are getting significant sleep at night, beyond your daytime sleep, the solution would require clinical consultation with a sleep clinician.