Causes

• Seasonal affective disorder is related to environmental light. Overcast weather and poor indoor lighting can exacerbate SAD.
  
  

White Light Therapy

• In white light therapy, bright lights are placed in a box that filters out ultraviolet radiation. The light box should be placed on a tabletop or stand, preferably at eye level or above.
  
  

Intensity

• White light therapy generally creates a light as intense as early morning daylight.
  
  

Duration

• The length of exposure depends on the intensity of the light, but daily sessions of 30 minutes are typical.
  
  

Time of Day

• Seasonal affective disorder relates to light's effect on your internal circadian rhythm clock; most patients benefit from morning white light therapy.
  
  

Side Effects

• Side effects to white light therapy are rare; however, some patients experience headaches, irritability, eyestrain, or nausea.