Prevention of Seasonal Affective Disorder

Seasonal Affective Disorder is a depression-related illness linked to the availability and change of outdoor light in the winter. Reports suggest that 0.4% to 9.7% of the world's population may suffer from SAD, with up to three times that number having signs of the affliction (called sub-syndromal SAD or S-SAD) without being classified as a major depression — primarily in Northern America and Northern Europe (Rosen, et al., 1990).

Light therapy with exposure levels at the eye of between 2500 lux (for 2 hours) or 10,000 lux (for 30 minutes) has shown to be an effective cure against SAD (Sloane, 2008). Exposure to daylight outdoors (~1000 lux) can also reduce SAD symptoms (Wirz-Justice et al., 1996).

So as seasonal mood disturbance is relatively common, the amount of daylight in our homes or workplaces can be of considerable significance. Dr. Craig Sawchuk, a Mayo Clinic psychologist, says one of the most effective treatments for seasonal affective disorder is exposure to artificial light or light therapy.