Dh. Avery et al., Bright light therapy of subsyndromal seasonal affective disorder in the workplace: morning vs. afternoon exposure, ACT PSYC SC, 103(4), 2001, pp. 267-274
Objective: Bright light therapy in seasonal affective disorder (SAD) has be
en studied extensively. However, little attention has been given to subsynd
romal seasonal affective disorder (SSAD) or the use of bright light in the
workplace. Many patients using bright light boxes complain of the inconveni
ence of use. Much of this inconvenience involves the often-recommended earl
y timing of the bright light therapy. Patients, who already have difficulty
awakening, often have difficulty using the bright light therapy soon after
awakening before going to work. If bright light could be used effectively
in the workplace, the treatment would be more convenient; the improved conv
enience would probably improve compliance. In this study, we studied the ef
fectiveness of bright light therapy in subjects with SSAD in the workplace,
comparing morning bright light with afternoon bright light.
Method: Morning and afternoon bright light treatment (2500 lux) were compar
ed in 30 subsyndromal seasonal affective disorder patients using the bright
light therapy in the workplace. Hamilton Depression Ratings and subjective
measures of mood, energy, alertness and productivity were assessed before
and after 2 weeks of light therapy.
Results: Both morning and evening bright light significantly decreased the
depression ratings and improved the subjective mood, energy, alertness and
productivity scores. However, there were no significant differences between
the two times of administration of the bright light treatment. Both bright
light treatments were well tolerated.
Conclusion: Bright light given in the workplace improves subjective ratings
of mood, energy, alertness and productivity in SSAD subjects. Morning and
afternoon bright lights resulted in similar levels of improvement.