Seasonal affective disorder (SAD) is depression related to the time of the year. The most common trigger is miserable weather, but past events can also trigger it, such as the death of a loved one or physical trauma.
SAD makes people sleep longer than usual because it saps us of our energy during the day. However, insomnia is strongly correlated to generic depression, and we can’t discount the possibility of SAD sleep issues.
Clinical research has linked SAD to changes in seasons, and you are more likely to have feelings of depression in winter - Britain’s grey, miserable weather is depressing to many people because it strips us of the outdoor lifestyle.
You may have SAD if you get depressed in winter or notice a difference in your mood when the weather’s foul. Some people feel SAD is triggered by past events like losing a daughter. If you can link your depression to times of past events, this is a good indicator that they are the trigger – and talking to someone will probably help
SAD and sleep
SAD is linked to poor sleep because shorter days and reduced daylight cause the brain to produce less melatonin (sleep hormone).
This explains why you find it harder to fall asleep during the winter. In a 2006 study, Oregon Health and Science University researchers found that melatonin supplementation can improve mood in winter depression.
Editor’s note on melatonin - melatonin supplements are only available on prescription in the United Kingdom, so speak to your GP.
The frustrating thing about SAD is it usually makes you excessively sleepy during the daytime when it is impossible to go to bed, so you are tired during the day and unable to fall asleep at night, creating a horrible cycle of wakefulness.
In healthy people, circadian rhythms (the internal body clock) properly manage the sleep-wake cycle. In depressed people, those circadian rhythms are interrupted, making falling and staying asleep more difficult.
This explains why you have bouts of tiredness during the day and struggle to sleep at night – because your sleep phases are out of whack.
Several papers (1, 2, 3) have considered the phase-shift hypothesis for SAD, finding that everything points towards problems with the circadian rhythm for sleep problems. Check out the linked papers for more information.
What are the treatments for SAD?
The National Institute for Health and Care Excellence (NICE) recommends treating SAD the same way as other types of depression.
NICE recommends cognitive behavioural therapy (CBT) and antidepressants, which target the activity of specific brain chemicals.
CBT is a talking therapy that helps you deal with irrational and damaging thoughts to manage the controllable elements in your life.
An interesting treatment is lightbox therapy, where a lightbox replicates the stimulus of sunlight to produce melatonin naturally.
The strange thing about British medical advice is that melatonin supplementation– shown to improve mood in patients with SAD – is not listed as a potential treatment in many cases, despite being available on prescription.
This study backs melatonin as a worthwhile treatment for winter depression, and this study supports it for the treatment of insomnia in people with autism.
However, depending on your physiology, melatonin supplements can interact with various medications and make you feel more tired.
SAD is real, so speak to someone!
SAD affects people at specific times of the year and can go away spontaneously after the depression phases out, perhaps due to better weather, more daylight, or after a traumatic time has passed. However, waiting for SAD to end isn’t good for your mental health or sleep, and it could lead to generalised depression.
We recommend getting professional help – start with your GP and escalate your problem if you don’t get anywhere. If you need to talk, try these mental health crisis helplines.