 Subjects will be instructed to begin daily 45-min sessions of exposure to the light each morning shortly after they awaken provided it is after 6 a.m.. Written instructions will be given, potential adverse effects will be discussed, and subjects will be instructed to telephone the supervising clinician either Dr. Anderson or Dr. Glod with any questions or should any adverse effects occur. A telephone appointment will be scheduled for 2-3 days after the first use of the light device. Patients who complain of feelings of jitteriness after using the light device will be advised to reduce their duration of daily exposure to 30 min per day. Patients who complain of headache after using the light device each day for 2-3 days will be advised to return for a visit to review the procedures they are using. An appointment will be scheduled for 7 days after the first use of the light device. Any patient who continues to complain of headache after the first week of light exposure will be withdrawn from the study. Patients who complain of feelings of jitteriness after using the light device 20 min per day will be withdrawn from the study. 