Seasonal Affective Disorder

Seasonal affective disorder (SAD) is a medical condition, a type of depression, that affects many people in the late fall, winter, and early spring.  The major cause of SAD is lack of sunlight.  SAD has been referred to as many things over the years, such as winter blues, winter depression, cabin fever, etc.  SAD was made a clinical diagnosis in the early 1980's.  On average only 2% of the population has SAD, the incidence of it goes up the farther north you live.  Women are twice as likely to have it as men.  Also, in Canada it is estimated that 20% of the population has some symptoms of SAD.  The symptoms are depression, lack of energy, increased appetite, lethargic, over sleeping, socially withdrawn, irritable, difficulty concentrating, and a low sex drive to name a few. One of the methods of treating SAD is with light therapy.  The therapy is provided through use of a light box or SAD light, which a person sits within two feet of for thirty minutes a day – typically first thing in the morning.  The SAD light emits a bright light simulating sun light, and should be a minimum of 10,000 Lux (a metric measurement of light intensity).  The light stimulates a receptor in the eye that in turn causes a chemical reaction in the brain, and is believed to help reset your circadian rhythms. The SAD light, sometimes referred to as happy lights, work for people with mild to very severe seasonal affective disorder. SAD light therapy is typically covered by most insurance companies, if the individual has a diagnosis of SAD, and a prescription for light therapy from their doctor.  The light box must produce 10,000 Lux.  Insurance companies tend to rent the light box for the first two months, and then purchase it if the therapy is successful.  You should check with your insurance company for specific coverage criteria – they may vary.  Many people purchase light boxes at their own expense because it makes them feel happier and more energetic in the winter.  You do not need a prescription to purchase them, only if you want an insurance company to pay for them. Liberty Oxygen and Medical Equipment provides light boxes for purchase and rental. We have seven Twin Cities locations, and we are a provider for most insurances: BCBS HealthPartners, Medica, Preferred One, Ucare. For more information on seasonal affective disorder visit:

The Society for Light Treatment and Biological Rhythms