Light is an interesting metaphor for many things, almost all of them positive.  There’s light at the end of the tunnel, eyes that light up, a person who lights up your life, a brilliant idea, a shining example, a beacon of hope, a glowing review, a bright future.

It comes as no surprise, then, as researchers examine disorders and sleep cycles, that light plays a significant role in alleviating the symptoms.  Light has long been recognized as a way to alleviate the symptoms of depression caused by seasonal affect disorder.  Seasonal affect disorder (SAD) is an alteration in mood brought on by the seasonal change in the length of the day.  It is intimately related to circadian rhythm and the amount of light our brains are exposed to during the day.  One type of treatment involves exposure to a light therapy box, which mimics the type of light you are exposed to when you are outside.  The best way to use a light therapy box is with indirect exposure for 30 minutes or longer in the morning.  You do not want to use the light round the clock–it is designed to be a mild zeitgeber to reset your biological clock, and affect the amount of melatonin being secreted by your suprachiasmatic nucleus.

What you may not know about, however, is the role light plays in therapies for Alzheimer’s disease and schizophrenia.  Both disorders are marked by disruptions in sleep.  Alzheimer’s patients are often placed in nursing homes not because of the specifics of their cognitive and physical decline, but because caretakers find it difficult to deal with nightly wandering.  A study begun in 1999 by Van Someren and his colleagues placed lightboxes on the ceilings of a group of Alzheimer’s patients, and no light boxes in a similar group.  Over the next several years, they monitored the activity of both groups, and found that the experimental group (with the light boxes) showed better moods and more regular sleep patterns than control participants.  More importantly, the group exposed to the light boxes showed a slower decline in cognitive abilities than the control group.

Schizophrenic patients also tend to be more active at night.  The work with Alzheimer’s patients and people suffering from depression using light therapy suggests that, in addition to the other symptoms and brain abnormalities, schizophrenics may also suffer from a disrupted circadian rhythm.  Research on the effects of light therapy for this disorder have just begun, but so far the results seem promising, though it remains unclear whether the light therapy is treating the negative symptoms of schizophrenia, or the symptoms of depression occurring concurrent with schizophrenia.

Alzheimer’s disease and schizophrenia are accompanied by a host of brain abnormalities, including loss of brain tissue.  It’s no surprise that the circadian rhythm of people who suffer from these disorders is affected.  What is surprising is how intimately linked to better health circadian rhythm is, but in retrospect, I think it shouldn’t be such a surprise.  We know many chemical and physical changes take place in the brain while we sleep, including the fact that slow-wave sleep allows the brain to rest, and REM sleep facilitates memory.  Why wouldn’t people with AD or schizophrenia, whose behavior is the most disrupted, also benefit the most from anything that keeps their circadian rhythm set properly?

And really, you don’t need to suffer from a disorder to benefit from good sleep habits.  Most of us are sleep deprived.  If you fall asleep within five minutes of laying down in bed, you are probably sleep deprived, and that will affect everything in your waking life.  Proper sleep is necessary for our nervous system to work properly, even if you are a healthy adult.  There’s a small irony that light, which we often associate with being awake, is also vital for proper sleep.  There are many sources out there with tips to help you get a good nights sleep:  set a schedule, relax before going to bed, avoid caffeine or alcohol.  One small thing you can do is to mediate for approximately five minutes before lying down.  If you are prone to falling asleep right away, sit up and meditate.  Empty your mind and try to relax, breathing deeply and slowly.  I tend to count breaths before I settle down to actually sleep, and it does seem to improve my sleep.

Hopefully, the end of the semester will allow you to get back to good sleep habits.  🙂