As the nights get longer and the temperatures and opportunities to be outside reduce many people start to feel blue. For some people this is more serious and the shorter days lead to depression or seasonal affective disorder (SAD). This form of depression affects about 1% to 2% of the population.
SAD comes on during the autumn and winter months and seems to be triggered by more limited exposure to daylight. It usually subsides in the spring. Symptoms are similar to general depression and include lethargy, loss of interest in once-pleasurable activities, irritability, inability to concentrate, and a change in sleeping patterns or appetite.
It is best to start treating SAD before symptoms begin if you know you are susceptible.
Here are some tips to reduce SAD:
Exercise – research shows that increased levels of physical activity can significantly reduce the odds of depression, even among people who are genetically predisposed to the condition. Engaging in several hours a week of any kind of exercise confers protection, including aerobic exercise, dance, exercise machines, yoga and stretching (1).
Gardening – is beneficial in many ways, particularly if done as part of a group such as a community garden project. Benefits come from the soil microbes, being outside, being with other people, and having a sense of purpose.
Spend Time in Nature – spending just 2 hours a week in nature has been show to benefit mood and well being.
Be Together – loneliness and isolation are major risk factors for depression. Even if it feels difficult try to spend time with other people every day, whether that is by joining interest groups, taking up a hobby, volunteering, inviting people round, or finding a friend who likes walking and talking.
Vitamin D – evidence suggests an association between vitamin D deficiency and depression, and there is a case for vitamin D supplementation in those with clinical depression who are vitamin D deficient (2,3). In the summer it is possible to get vitamin D from the action of sunlight on bare skin but during the winter supplementation is recommended. Look for vitamin D3 with K2.
Light Therapy – also called phototherapy, involves sitting close to a full spectrum light for 30 minutes every morning. The light must enter through the eyes as skin exposure has not been proven to work. Most people require at least a few days of treatment, and some need several weeks. Light boxes can be bought for home use but it is best to work with a professional as a few people experience side effects such as manic episodes, headaches, eye strain and rashes. Some medications and herbs, such as St. John’s wort, increase sensitivity to light.
Melatonin and SAD – the brain secretes melatonin at night, so longer periods of darkness in the winter may mean more melatonin is produced. Light therapy or spending time outside may reduce SAD because exposure to light decreases melatonin production.
Body Clock and SAD – another theory is that an out-of-sync body clock may contribute to SAD. Each of us has a biological clock that regulates the circadian rhythms of sleeping and waking as well as controlling bodily functions such as body temperature, blood pressure, and the release of hormones. Although the body clock is largely self-regulating, it responds to light and melatonin production. Light therapy may help to reset the body clock. It is also recommended to go to bed and get up at similar times each day, rather than having long lie-ins, tempting as that may be.
The blog post The Microbiome and Mood shows there is increasing evidence for the gut microbiome as a key factor in the link between diet and depression and what you can do about it. The blog post on Diets for Depression gives some ideas about which foods and diets can help improve your mood.
- 1. Depression and Anxiety, Physical activity offsets genetic risk for incident depression assessed via electronic health records in a biobank cohort study. Choi K et al.
- 2. J Affect Disord. 2017 Jan 15;208:56-61. Vitamin D and depression. Parker GB, Brotchie H, Graham RK.
- 3. Pharmacol Rev. 2017 Apr;69(2):80-92. Vitamin D and Depression: Cellular and Regulatory Mechanisms. Berridge MJ