Sarah Ewing

LONG SUNNY days mean happy days because sunlight provides us with much-needed Vitamin D, which affects our hormones and immune system. When winter arrives and the days are darker, it's easy to feel down and listless. But one in five Scots is really hit badly, and winter signals the start of SAD (seasonal affective disorder). Symptoms include insomnia, lethargy, anxiety and loss of libido, and usually disappear within a month of spring starting.

Women are three times more likely than men to suffer and Scots are more prone due to the reduced hours of sunlight compared to the rest of the UK. On average, Scotland received only 31 hours of sun in December, compared to 51 hours in England. Don't despair, though - there are several things you can do to keep your winter blues from taking over.

Light therapy Light therapy emits natural light to help boost the production of Vitamin D, as sunlight would during the better weather - but without the harmful UV rays.

Folic acid, also know as folate, is a water-soluble B vitamin that is crucial for brain function. People with depression are more likely to have low levels of folate and this reduces serotonin levels. Folic acid works in conjunction with SAMe to control blood levels of the amino acid homocysteine, elevated levels of which have been linked with depression.  Basil is a green herb native to tropical Asia and Africa, more commonly used to flavour pasta dishes. Medical herbalists prescribe it to treat depression and winter blues because of its dual sedative-stimulative effects, including reduction of anxiety, insomnia and fatigue. It also helps encourage mental clarity and concentration. The leaves can be boiled to make a tea. You can buy it from any good grocery store, from approximately £1.89 for a fresh potted plant.

Rhodiola is a green, sweet-smelling herb that grows in the cold regions of the world, including Russia, the Arctic and the Alps. It's an adaptogen which helps your body cope with increased levels of mental and physical stress. It has been shown to increase serotonin levels by 30% and two compounds within it, rosavin and salidrozid, help transport trytophan and 5-HTP to your brain.

5-HTP is an amino acid that is required to convert tryptophan into serotonin. Several studies have shown it to be more effective than pharmaceutical anti-depressants in treating mild to moderate cases of depression. 50mg one to three times a day is recommended.

St John's Wort (aka hypericum) is thought of as the herbal depression panacea because it increases production of the happy hormone serotonin. A study in Current Medical Research and Opinion showed a 40% reduction in symptoms, such as insomnia and loss of sex drive. But the caveat is that it can render contraceptive pills useless, so consult your pharmacist first.

Air quality Air ionisers increase the concentration of negative ions in the air. Negative ions have been linked to an increase in serotonin, according to recent trials where patients were exposed to an air ioniser at home for 30 minutes every morning for three weeks.