If you get the blues every winter - or if you suffer from the more serious form of winter depression known as seasonal affective disorder (SAD) - you may already have taken to hiding under your duvet at every possible opportunity.
"Just as it's natural for us to feel more energised and happy when the sun is shining, research has shown many of us feel miserable and lethargic with a tendency to eat and sleep more in winter," says Professor Farmer, who specialises in treating winter depression.
Around 17 suffer from SAD. And like other forms of depression, more women are affected than men.
The reason for all that low mood and lethargy is the lack of natural sunlight, experts claim. And the really bad news is that sufferers may feel low from the end of October right through until the spring.
If, however, you're determined not to hibernate this winter, give these tips for keeping SAD and the winter blues at bay a try:
Stay active Beat the blues with a daily walk outdoors. As well as exposing you to natural daylight, exercise boosts your energy levels and immune system too. Try getting outdoors during your lunch hour, even if it's raining, as the more natural daylight you're exposed to the better.
Eat well While you may feel like gorging on sweet, stodgy foods, your confidence will take a knock if you gain weight. Even though it's particularly difficult at this time of year, stick to your normal healthy diet.
Have a banana Low levels of the hormone serotonin may play a part in triggering SAD symptoms, so include foods in your diet that help boost serotonin levels such as bananas, turkey, chicken, cottage cheese and avocado.
Boost your D SAD is also linked with low levels of vitamin D, thanks to the lack of sunshine in winter (vitamin D is manufactured in your skin when its exposed to sunlight). So eat more D-rich foods such as grilled oily fish, margarine and eggs, or take a vitamin D supplement.
See the light Lamps designed to simulate strong, natural daylight are thought to benefit around 85% of SAD sufferers. You simply sit in front of the lamp for around an hour a day during the winter months.
Socialise You may not be keen on going out much at night, but spending time with friends and family helps prevent winter depression - so don't give in to the temptation to stay home alone.
Talk about it If your symptoms are starting to have a serious affect on your day-to-day life, talking to a counsellor, psychotherapist or cognitive behavioural therapist may help.
See your GP Again, if your symptoms are bad, ask your GP about possible antidepressant treatments that might help you get through the winter.