I keep reading about seasonal affective disorder (SAD), but I don’t know of anyone who’s ever had it or knows anyone who has. Is it just another load of media hype?
Gareth Noakes, Hereford

SAD is a genuine medical condition – a specific type of depression caused by a lack of exposure to daylight. This is why in winter many people experience symptoms such as tiredness, overeating and lack of sex drive and concentration. The arrival of spring and more daylight means the symptoms spontaneously disappear, but taking more exercise and spending more time outdoors during the daylight hours in winter can help.

Getting enough rest, reducing stress, taking regular exercise and eating a healthy diet with plenty of fresh fruit and vegetables will all help boost energy levels and lift mood. Bananas, for example, can help because they contain tryptophan, which the body converts into serotonin, one of our natural feel-good chemicals. Light therapy, antidepressants and the herb St John’s wort have also been used to treat SAD.