SAD disorder is usually triggered by the changing of seasons from summer to autumn/winter, and shows various symptoms and levels of severity.
Symptoms of SAD and the severity of them can vary from person to person. Whilst some people may only notice minor fatigue or food cravings, for some they can be severe feelings of depression and lack of interest in activities.
SAD is currently estimated to affect around 6% of the UK population, although in higher latitude countries this figure is estimated to be closer to 8%. For some the symptoms are minor, while for others they can be debilitating and stop people from going to work or school.
Because the illness can often lead to binge eating and resultant weight gain, the opposite to major depressive disorder, SAD is often mistaken as being a lighter disorder than depression. However, experts have said that the illnesses are two sides of the same coin.
Brenda McMahon, a psychiatry researcher at the University of Copenhagen, said: “People who truly have SAD are just as ill as people with major depressive disorder.
“They will have non-seasonal depressive episodes, but the seasonal trigger is the most common. However it’s important to remember that this condition is a spectrum are there a lot more people who have what we call sub-syndromal SAD.”
Whilst 6% of the population are directly affected, 10-15% are estimated to have sub-syndromal SAD, meaning they find it more difficult to get through the autumn and winter months, while one in three may suffer from ‘winter blues’, characterised by feelings of disinterest and fatigue.
Whilst experts are not completely clear on exactly what causes the disorder, many believe that it is linked to our ancestors. Robert Levitan, a professor at the University of Toronto said: “Because it affects such a large proportion of the population in a mild to moderate form, a lot of people in the field so feel that SAD is remnant from our past.