How is light therapy done?
Most light therapy is prescribed at 10,000 lux for about 30 minutes to 2 hours in the early morning. Studies vary as to whether light therapy at other times of the day is less effective, but some people with SAD (perhaps those who wake up normally in the early morning) should do their light therapy for 1 to 2 hours in the evening, ending 1 hour before bedtime. Most research shows that light box therapy is more effective than dawn simulation. But some people who find it inconvenient to use a light box may want to try dawn simulation. When you begin light therapy, your initial response will determine whether you need to adjust the intensity or duration. Many people respond to light therapy within 3 to 5 days, but they may relapse back into depression if they miss treatment for 3 days in a row during winter.1 If you don’t respond to treatment within the first week, you may notice improvement in the second week. The most common side effects of light therapy include headache, eye strain, an
