The authors investigated the outcome of an alternating time schedule
versus two fixed schedules (either morning or evening) of bright light
treatment for seasonal affective disorder. The subjects were 31 patients
who met DSM-III-R criteria for major depression with a seasonal pattern. No
statistically significant difference was observed among patients in the
three groups for response criteria after 1 week of treatment. These results
support the use of more flexible phototherapy schedules.