As many as 90% of us report that our mood and energy levels are affected by the change in the seasons and we change our lifestyle in reaction to this. Some of us slightly eat and sleep more. As many as 1 in 5 of us, with a firm dislike of the gloomier shorter days, suffer from a drop in mood, which is commonly referred to as ‘winter depression ‘or ‘the winter blues’.
For others (about 7%), the symptoms are more severe leading to problems coping during the darker winter months suffering a condition called Seasonal Affective Disorder (SAD). The symptoms of SAD include increased sleep (combined with difficulty getting to sleep and poor sleep quality), severe daytime sleepiness, excessive eating, a craving for carbohydrates and depression.
What is the cause?
The cause of SAD remains unknown, however, it has a genetic component (it runs in the family) and is often associated with Bipolar Disorder. Scientists believe SAD involves problems in the regulation of the hormone melatonin, which gives us the desire to sleep. Here, in the darker winter months SAD sufferers have an over production of Melatonin leaving them to feel lethargic, sleepier and affecting the body clock. It is also thought that SAD involves a reduction in Serotonin activity in the brain during the darker winter months. Serotonin is one of our key neurotransmitters; its reduction causes problems with mood, appetite and sleep and is linked to feelings of depression.
It is thought that the combination of increased melatonin and decreased Serotonin, affects our body clock or circadian rhythm. This rhythm is tuned into the light-dark changes, which naturally occur throughout the year. It would seem that for SAD sufferers the impact of changes of day length in the winter are timed differently. Therefore, making it harder for their bodies to adjust.
Finally, SAD sufferers have reduced production of Vitamin D in the darker months. Vitamin D is created in the skin by ultraviolet B (UVB) sunlight and low levels are associated with low mood and depression.
See your GP
Phototherapy including bright light in the early morning has been shown to be an effective treatment for seasonal depression. However, if you think you suffer from SAD you should not try to treat yourself and need to see your GP.
I hope you enjoyed reading about Seasonal Affective Disorder and it was informative for you. For more sleep information read my previous article here.