What is ASPD?
This is a sleep disorder where you keep going to bed and waking up too early. For example, you might find it hard to stay up until a normal bed time such as 10pm. You might feel a strong urge to go to bed as early as 8-9pm. Once in bed you fall asleep quickly and sleep well for a few hours. However, you then wake up very early (e.g. 3-4 am) and find it very hard to go back to sleep. You often feel you don’t get enough sleep, due to waking up so early in the morning. Importantly, if you went to bed even earlier (e.g. 6-7pm), you would be able to go to sleep then. But you would probably wake up even earlier after a few nights of this early-to-bed pattern.
What causes ASPD?
A vital part of what makes us feel sleepy is our twenty-four hour body clock. This is located deep inside our brain, behind the eyes. It controls when we feel sleepy and alert. For most adults their body clock makes them feel sleepy between the hours of 11pm to 7am and alert at other times, including the early evening (6-9 pm) and morning hours (8-11 am). Those with ASPD have an early timed body clock that shifts those alert and sleepy zones to earlier clock times. This makes them feel very sleepy in the early evening and alert as early as 3-4 am. How the ASPD body clock timing shifts in this way is not well understood. It may be due to a shorter than normal cycle length, tending to complete the sleep-wake cycle in less than twenty-four hours.
How common is ASPD?
ASPD is more common as we become older. This is in contrast to delayed sleep phase disorder that mainly affects young people. Roughly one percent of middle aged to older people experience ASPD.
How does it affect people?
Apart from being inconvenient, ASPD can cause insomnia in the early morning, insufficient sleep, daytime sleepiness and fatigue. It can also increase the risk of depression.
How is it treated?
Based on the knowledge that ASPD relates to an early timed body clock, the aim of treatment is to change the body clock to a more normal timing. Two treatments can re-time the body clock: getting bright light visual stimulation and taking melatonin.
The timing of when you have these is vital. Bright light visual stimulation should occur in the evening before you go to bed. The light should be brighter than normal indoor lighting. You can obtain it from specialised light boxes, or portable devices that you can wear, e.g. eye glasses. A few examples can be found by a web search for “bright light therapy”. You may need an hour or two of bright light therapy before bed. Some will benefit from nightly use for a week. Others will need longer, sometimes several weeks, to get maximum benefit. It is best used late in the evening, perhaps turning the bright light device off half an hour before bed.
Melatonin(the hormone of sleep) also helps to reset the body clock. One option is to take a 2mg slow release melatonin tablet (Circadin™) as close to your new (later) bedtime as possible. A second option is to take a small dose of melatonin (0.5 mg), about half way through your sleep period. This could be at a time when you wake up on your own.
To change your hours of sleep, you should gradually delay your bed time (e.g. twenty minutes later each night) until you get it to the time that you want. As you delay your bedtime, you will also be delaying the time of your bright light exposure and melatonin intake.
As you can see, this treatment is quite complex. You may want to consult a sleep specialist, especially if you don’t have success treating ASPD by yourself.
Can I prevent it coming back?
The reason that your body clock “sped up” in the first place may still be present, even after you move your sleep period back to the time you want. When you stop treatment, your sleep period may then slowly creep to be earlier again. So you may need to use the bright light and / or melatonin every now and then. To prevent relapse, you may also want to avoid bright light for the hour or two after you get up in the morning. Wearing sunglasses in the morning when outside can help, especially in the sunnier summer months.
What might your doctor do?
It would be easier for your doctor to be sure of this disorder if you keep a sleep diary for a least a week. Also record the times across the day and night that you feel most sleepy and most alert. Your doctor would be able to prescribe melatonin and, if felt necessary, refer you to a sleep specialist.