The main symptom is depression, but other telltale signs of this condition include developing an increased appetite with strong cravings for carbohydrates and sweets, weight gain, fatigue, wanting to sleep for longer and get up later, plus an energy slump in the afternoons.

SAD has now been linked by researchers with a decrease in the levels of those hormones and brain chemicals that control both mood and sleeping patterns which means that you can use a number of alternative remedies which trigger an increase production of these substances to try and redress this imbalance.

The most important hormone that the body relies on regulate the bodyclock is melatonin. In animals, it controls seasonal behaviour, including hibernation. Although available in supplement form over-the-counter in America, it is not licensed in the UK and is a prescription-only medicine. So what alternative health practitioners here do, is take a clever step back in the biochemistry of the brain to increase the production of the chemicals that the brain then uses to melatonin.

One of these is serotonin. As well as controlling sleep patterns, body temperature and even your sex drive, this neurotransmitter works in the body to ward off depression. Serotonin is available in supplement form but increased production in the brain is also triggered by the herb, St John’s Wort, which is frequently used by herbalists to treat mild to moderate depression and which, in Germany, is now prescribed three times more than Prozac.

You can safely self-prescribe St John’s Wort in those countries where it is still available in health stores, but in Ireland the government voted earlier this year to make a prescription-only remedy - which means you will have to get it from a qualified health practitioner. This ban on over-the-counter sales followed a small number of reports of adverse side-effects, but only among those already taking anticoagulant medication and among a very small number of women who had been taking the contraceptive pill for several years.

One of the most important triggers for the production of serotonin is natural daylight but, since 90% of us spend 90% of our time indoors, especially at this time of the year, you will need to make a special effort to get outside to benefit from it. Those suffering with full-blown SAD symptoms tend, instead, to compensate with the use of specially developed light boxes and even light bulbs that simulate natural daylight indoors.

Another natural winter mood-booster is an amino acid called L-tryptophan, which is a precursor to serotonin that is found in foods as diverse as roasted pumpkin seeds, baked potatoes with their skins on and a seaweed called kelp. To make serotonin, the body also needs a good supply of vitamin B6, which is found in carrots, fish, lentils, peas, potato, spinach and sunflower seeds - so it is a good idea, at this time of the year, to increase your dietary intake of all these.

In the Middle East, basil, a herb we associated more with Italian cooking and pasta dishes, is made into a tea that is taken to relieve mild depression. It has a long history in Ayurvedic (traditional Indian) medicine as a good herb for the treatment of nervous disorders and anxiety and, in aromatherapy, the essential oil can even have a mildly sedative effect.

Exercise is an excellent antidote to the winter blues since working the body releases chemicals called endorphins which are the body’s own feel-good chemicals that create a natural feeling of wellbeing. To benefit from this, try to incorporate two or three 30-minute exercise sessions into your routine each week.