Written by Dr. Daniela Steyn
I have a sunlight-bright light at home. I purchased it in 2010 during my first Winter in Canada. My office didn't have any windows. I would get to work in the early morning in the dark and leave again in the dark.
Seasonal Affective Disorder (SAD) is a type of depression that occurs in a seasonal pattern, typically during the fall and winter months when daylight hours are shorter. It is estimated that around 5% of the population experiences SAD, with symptoms ranging from mild to severe. SAD wasn't something I clinically encountered with my patients in South Africa, as South Africa is blessed with abundant sunshine year-round.
However, in preparing for my Canadian Medical Board Exams, I learned everything I needed to know about Mental Health from a Canadian aspect. With so much evidence for bright light therapy, I purchased my bright light as soon as the days became shorter. Interestingly, my patients in Alberta, where one would have gorgeous sunny days, even when the temperature was -40'C, didn't struggle as much with SAD as when I worked in Vancouver, where it is rainy and overcast for extended periods, or this year in Toronto, where my patients have only had about 1/3 of the sun they usually have.
Over the years, researchers and clinicians have explored various treatment options to alleviate the symptoms of SAD, and one modality that has emerged as a promising therapeutic approach is Bright Light Therapy (BLT).
Bright Light Therapy involves daily exposure to bright artificial light, usually in the form of a lightbox or light panel, which emits a specific wavelength of light that mimics natural sunlight. The treatment duration ranges from 30 minutes to several hours, depending on the individual and the severity of symptoms. BLT has proven to be an effective treatment for SAD, and it is now recognized as a first-line therapeutic modality.
The history of SAD and BLT dates back several decades. In the 1980s, researchers began to investigate the role of light in mood regulation and its potential impact on seasonal mood disorders. Studies conducted at that time suggested a link between decreased exposure to natural light and the onset of depressive symptoms in individuals living in high latitudes. This observation led to the development of BLT as a targeted treatment for SAD.
More recent research has focused on unravelling the underlying mechanisms of SAD and how BLT exerts its therapeutic effects. Studies have shown that individuals with SAD exhibit shifts in their circadian rhythm, the internal biological clock that regulates sleep-wake cycles and other physiological processes. These circadian disruptions are thought to contribute to the onset of depressive symptoms. BLT has been found to help regulate the circadian rhythm, leading to improved mood and a reduction in SAD symptoms. I recommend bright light therapy to my insomnia clients as well.
Additionally, alterations in serotonin reuptake, a neurotransmitter involved in mood regulation (your happy hormone!), have also been implicated in the pathophysiology of SAD. BLT has been shown to modulate serotonin levels in the brain, potentially contributing to its antidepressant effects. The combination of circadian rhythm regulation and serotonin modulation makes BLT a helpful treatment strategy for SAD.
Beyond its use in SAD, BLT has also shown promise as an experimental treatment for non-seasonal unipolar and bipolar depression, as well as other psychiatric disorders associated with circadian disruptions. Preliminary studies have explored the efficacy of BLT in these conditions, and while further research is needed, initial findings are encouraging. I am comfortable to recommend BLT to the majority of my patients. (see your healthcare provider for your unique situation ).
Moreover, BLT has been investigated as a potential treatment for eating disorders and attention-deficit/hyperactivity disorder (ADHD). In individuals with eating disorders, disruptions in circadian rhythm and mood disturbances are common. BLT may help regulate these disturbances and improve overall wellbeing. Similarly, individuals with ADHD often experience difficulties with sleep and mood regulation, and BLT could serve as an adjunctive therapy to alleviate symptoms.
In conclusion, Bright Light Therapy is an easily accessible, convenient, and valuable treatment option for Seasonal Affective Disorder, with a growing body of evidence supporting its efficacy. I like to implement small strategies for clients in my wellness clinic to elevate their health and wellbeing; this is one of them: try the power of light to improve your mental health and wellbeing yourself.