As the nights draw in and the temperatures drop, it's not uncommon for some of us to experience disturbed sleep and even seasonal depression.
Why are we so affected by this seasonal change, and what can we do to improve our sleep and state of mind over the winter months?
Seasonal affective disorder
Seasonal affective disorder (SAD) is a mood disorder that typically strikes in the fall and lasts through the winter months.
- Social withdrawal
- Sleep issues such as insomnia and hypersomnia
The link between sleep issues and SAD
A study published in the mid-1990s in the Journal of Psychosomatic Research found that of 293 individuals with SAD, 80 percent complained of winter hypersomnia, and 10 percent complained of insomnia.
Only five percent reported no sleep difficulties.
A more recent study involving just under 5,000 individuals found that of those with SAD:
- 16 percent experienced frequent nightmares
- 25 percent reported frequent symptoms of insomnia
- 26.3 percent reported using hypnotics during the last month
- 30.4 percent had been diagnosed with depression during the past year
- 24.3 percent reported using antidepressants during the last month
To put these numbers into perspective, in those without SAD, only:
- 2.4 percent experienced frequent nightmares
- 7.6 percent reported frequent symptoms of insomnia
- 7.6 percent reported using hypnotics during the last month
- 4.1 percent had been diagnosed with depression during the past year
- 3.6 percent reported using antidepressants during the last month
Who is at risk for SAD?
The study found that compared to those without SAD, those with the disorder were more likely to be women, night owls, and short (six hours or fewer) or long (nine hours or more) sleepers.
A separate study found that those living in an urban environment were more likely to have a mood disorder compared to those living in more sparsely populated areas.
Why is SAD linked to sleep issues?
Sleep issues are a common symptom of depression, so it perhaps makes sense that SAD, which is a form of depression, appears to influence sleep.
One study found that the circadian rhythm of those with SAD may be supersensitive in the winter, making them more vulnerable to the effects of light deprivation.
Inconclusive link between light deprivation and SAD
It's worth mentioning that studies investigating the link between light exposure and prevalence rates of SAD have been inconclusive.
If winter light deprivation was to blame for SAD, we would expect to see higher prevalence rates at higher latitudes; yet this doesn't appear to be the case. In fact, one study suggested that climate, genetic vulnerability, and societal and cultural influences may have a more important role.
How to improve wintertime sleep_Increase your exposure to light _. Expose yourself to as much natural light as possible to help strengthen your body's internal clock. If you feel that's just not possible, you may want to invest in a light therapy lamp.
If you choose that route, I recommend using a light therapy lamp that emits between 5,000 and 10,000 lux and to use for it for about 30 minutes early in the day.
_Discuss melatonin supplements with your doctor _. Researchers at Oregon Health & Science University found that taking low-dose melatonin in the afternoon may help alleviate the symptoms of SAD by realigning the circadian rhythm.
If you feel your body clock is completely out of sync, melatonin supplements may be worth considering. However, you should speak to your doctor before taking melatonin to improve sleep.
_Check your thermostat _. Avoid the temptation to crank up the thermostat at night! If your bedroom is too warm when you go to bed, you may find it more difficult to fall asleep and stay asleep.
_Watch your diet _. Food has a huge influence on our overall sleep health.
In the winter, you may be more tempted to load up on comfort food, which doesn't always have a positive effect on sleep.
The holiday season can also lead to higher consumption of alcohol, and New Year diets can further hinder sleep.
_Do not ignore depression or sleep issues _. Sleep issues and feelings of depression shouldn't be ignored or shrugged off. If you feel depressed, talk to someone. If you feel suicidal, you can contact the National Suicide Prevention Lifeline on 1-800-273-8255. They also have an online chat service, and they are available 24 hours every day.
Martin is the creator of Insomnia Land’s free insomnia sleep training. His online course uses CBT techniques to teach participants how to fall asleep without relying on sleeping pills. More than 4,000 insomniacs have completed his course and 97 percent of graduates say they would recommend it to a friend.