A reader asks:

 I think I have delayed sleep phase syndrome (DSPS). I took the Automated Morningness-Eveningness Questionnaire and got some interesting suggestions I’d like to try. Even when I get sleepy in the evening, I tend to stay up for an hour or two or three, and then the next thing I know, it is 1:45 a.m. (or 2:45 a.m.) and I have an alarm set for 7:30 a.m. I’ve tried taking melatonin and Benadryl, but they don’t have any effect. If I fall asleep so easily, the question of why don’t I just get into bed at a “reasonable” hour is one that plagues me. I just can’t seem to change the habit, even though I really want to. I’m going to try setting a light on a timer next to my bed at the survey’s recommended time of 6:45 a.m. But with my additional habit of pushing past my sleepiness in the evening, will this help?

Answer:

Definitely worth a try, since by resetting your internal clock earlier with the light, you are less likely to want to stay up late. Keep in mind, though, that the intensity of the light you use at 6:45 a.m. is an important factor that may require adjustment during your trial. Although ordinary bedroom lamps might work for you, they might be insufficient.