The Scientist Behind SAD

When psychiatrist Norman Rosenthal moved from South Africa to the US in the 70s, something changed. In the colder winters of New York he and his wife felt their energy levels slump and their mood drop. So when he met fellow scientist Alfred Lewy at a party, it was easy for the pair to begin chatting about Lewy’s research into melatonin, a hormone associated with sleep – and how light and mood might be entwined. Which is how, more than 30 years ago, the pair became the first scientists to describe seasonal affective disorder – and treat it with light therapy. Since then our understanding of the way light affects us, Rosenthal tells me, has “skyrocketed”.

Sad, which is characterised by cognitive problems, withdrawing from friends and family, weight gain and increased time spent sleeping, may affect one in 20 people in the UK to a disabling degree. But as many as one in five can suffer the effects of less severe “winter blues”, struggling through darker days being less productive and happy than normal.

“Sad helped us recognise that light and dark are strong influences of mood and behaviour and many of us don’t get enough light,” says Rosenthal. “But now we know a large percentage of the population has some lack of functionality in the winter.”

His work opened up new fields for exploration. For instance, it is now understood that light therapy – using light boxes to mimic the effects of the sun’s rays – can help people with forms of depression that are not seasonal. It’s useful for patients for whom medication is a tricky option, such as pregnant women and the elderly.

Read the full story here: