Brightspark therapeutic light box for Seasonal Affective Disorder and related conditions, by Lumie, United Kingdom, 2005-2010

Seasonal Affective Disorder (SAD) is a seasonal pattern that can produce a wide variety of symptoms which each person will experience differently. These include a lack of energy, difficulty concentrating, feeling low, sad, anxious or angry, changes to sleep and appetite patterns and symptoms of depression.

The exact cause of SAD is not understood, but it is often linked to reduced levels of sunlight through the winter months. It is suggested that this can cause a lack of serotonin or an abundance of melatonin. Light boxes are said to work by creating a simulation of sunlight, allowing the melanopsin receptors in the eyes to trigger the release of serotonin. Each person who uses light therapy for SAD must purchase their own light box as these are not available on the National Health Service. Some people find them beneficial while others do not. More research is needed to fully understand the condition’s causes and treatment.