Seasonal affective disorder (SAD) – a type of depression that changes depending on seasonal patterns – is thought to affect as many as 1 in 15 people in the UK during the months between September and April.
Symptoms can include persistent low mood, low self-esteem, anxiety, and loss of interest in normal everyday activities.
But "there are lots of simple, practical things that can be done to help alleviate the symptoms of SAD," Stephen Buckley, head of information for the mental health charity Mind, told BuzzFeed News.
Here are some suggestions:
1. Physical activity can help to lift your mood and energy levels.
"While you may not feel like it during the winter, physical activity can be very effective in lifting your mood and increasing your energy levels," Buckley said.
"It doesn't have to be anything particularly strenuous – doing housework, gardening, or going for a gentle walk can all help.
"Research shows that outdoor exercise, such as cycling or jogging, can be as effective as antidepressants in treating mild to moderate depression."
2. Make the most of natural light.
"Going outdoors, particularly around midday or on bright days, can be effective in reducing symptoms, even if it's just taking a short stroll after lunch," Buckley said.
"If you can afford it, a holiday to a sunnier climate is likely to reduce symptoms, but you may find that on returning to the UK your SAD will temporarily become much worse."
3. A healthy, balanced diet is as important for your mental health as your physical health.
"As tempting as it is to reach for comfort foods to cheer you up, eating lots of foods high in fat and carbohydrate can often cause blood sugar levels to crash, resulting in sluggishness. It may also increase your anxiety levels," Buckley said.
"A healthy, balanced diet is as important for your mental health as your physical health, so it's best to include lots of fresh fruits and vegetables, as well as fatty oils such as omega-3 and 6. Some people find that taking extra vitamin B12 is helpful."
4. Boost your "feel good" hormones, says nutritional therapist Naomi Mead.
"Our levels of the 'feel good' hormone serotonin can be naturally boosted by the foods we eat," she told BuzzFeed News.
"Tryptophan is an amino acid converted in the body to serotonin, and can be obtained through our diet in bananas, poultry, eggs, and dairy products."
You could also try taking fatty acids. "Essential fatty acids – particularly the omega-3 fatty acids found in abundance in oily fish – have been linked to healthy brain activity, and are recommended to those contending with SAD," Mead said.
5. Try to increase your food sources of vitamin D.
Mead said that from October to April, 90% of the UK lies too far north to have enough sunshine necessary for our bodies to make vitamin D naturally, and a large proportion of the population in the UK is thought to be vitamin D deficient.
"Researchers are now discovering that vitamin D may play a very important role in mental health and depression. Studies have shown an association between low vitamin D levels and various mood disorders including depression and SAD," she added.
"Vitamin D can be taken as a dietary supplement in the D3 form. In addition, try to up your food sources of vitamin D, which include oily fish, eggs, and fortified foods such as cereals."
6. Team-building exercises at work are a great way of improving your mood in the office during the winter months.
"Regular exercise has been proven to reduce stress, boost self-esteem, improve mental clarity, and increase motivation, all of which are positive attributes for improved work performance," Mead said.
"In fact, one study actually found that employees devoting 2.5 of their work hours a week to exercise, got as much done with their time as those employees who did not work out in their regular hours.
"As an employer, organising team-building exercises such as wall climbing and trampolining could be a great way of improving mood and motivation in the office during the winter months."
7. Find something you enjoy, even if it's something small.
"Creative activities like painting and photography can be good ways to channel energy in a positive way – and, of course, they can help people to meet others with similar interests, and fill those long and gloomy winter evenings," Sarah Murphy, head of advice and helplines at the charity Rethink Mental Illness, told BuzzFeed News.
"There are also clubs for everything from reading, to learning a new language, to running, to knitting," she said. "See what might interest you and check out what's available in your local area by going online, checking notice boards in shops and supermarkets, or by contacting your local council."
8. Cut down alcohol.
"Research suggests that regularly drinking too much alcohol may cause depression," Murphy said. "Try to avoid it, and instead drink plenty of water, juices, or smoothies to keep your energy levels up."
9. Talk to someone you trust.
"It's very easy to become isolated if you are feeling unwell or are caught up with looking after someone else who is experiencing difficulties," Murphy said.
"Talking to someone you trust – a family member, a friend, or perhaps a teacher or tutor at college – can help you 'share the load'."