With the clocks going back and nights getting longer, some specialists are arguing that coffee bars, which provide high-strength lighting along with their lattes, might help the one in five people who suffers from seasonal affective disorder (SAD), a type of depression triggered by lack of light in winter. An estimated 7 per cent of Britain’s population suffer from SAD, with a further 17 per cent experiencing a milder form of the condition, commonly known as the “winter blues”. SAD kicks in as the days get shorter, the loss of natural daylight triggering depressive symptoms such as lethargy, a lack of interest in sex and sleep problems.
Light cafés have taken off in Sweden, which has nearly a million SAD sufferers and where winter gloom is a far greater problem than in the UK. Stockholm, for example, gets only five hours of daylight in the winter months. But the city’s commuters can stop off in cafés, such as the Iglo, and sit bathed in UV-free lighting to the strength of 3,000 lux (the technical measure of brightness).
This intense light, which compares with the 200-500 lux emitted by domestic or office lighting, simulates natural light and is thought to correct the hormone imbalance that causes SAD, although its effectiveness has not been conclusively proved.
Dr Victoria Revell, an expert in chronobiology (the study of circadian rhythms) at the University of Surrey, says that the cafés would benefit British SAD sufferers.
“They are beneficial both physiologically and socially. Using light therapy in this way can help our sleep patterns, energy levels and performance.”
Dr Revell explains: “One key role of light is to synchronise our circadian body clock to the 24-hour day.” SAD sufferers, she says, require a higher light intensity to regulate their body clocks. In the winter, when light levels are lower, they produce too much melatonin (the hormone which helps us sleep) and less of the “feel-good” hormone, serotonin.
The latest thinking is that the disorder has genetic origins. In America, for example, research suggests that mutations in a gene associated with melanopsin – a light-sensitive pigment in the retina of the eye thought to help regulate our circadian rhythms – may be involved.
Not all doctors agree: the Royal College of Psychiatrists recommends 30 minutes to one hour of light therapy daily, which some studies show is effective for 50-85 per cent of cases. Commercial lightboxes vary in price from £35 to £200, depending on the light intensity delivered, but 2,500 lux is the minimum needed to work. Some light devices are portable for travel or office use.