Light therapy and fluoxetine both induced remissions in about half of
patients with winter seasonal affective disorder (SAD)—even those who
were severely depressed, Canadian researchers found in a double-blind,
randomized, controlled trial.
Two-thirds of patients using either firstline treatment showed a clinical
response, according to Raymond Lam, M.D., a professor of psychiatry and head
of clinical neuroscience at the University of British Columbia, Vancouver. The
results of the study, known as Can-SAD, were published in the May American
Journal of Psychiatry.
While light therapy worked a little faster than fluoxetine and triggered
slightly fewer patient-reported adverse events in two-month trials, subjects
tolerated both treatments well. Absent clear superiority for either light or
fluoxetine, patient preference should guide treatment selection, the
"Patients often prefer light therapy, but physicians always wondered
whether light was as good as drugs," Lam told Psychiatric News."
Now we have evidence to support the decision to use light as a
first-choice treatment for patients with winter depression."
The researchers compared the two therapies in 96 adults with SAD at four
centers over three winter seasons, 2000-2001 through 2002-2003. Their
eight-week treatment protocol is the longest controlled light therapy study to
date. It also is the first to run as long as the standard clinical trial for
All participants had moderate to severe depression, as indicated by the
Structured Clinical Interview for DSM-IV and scores on Hamilton
depression rating scales. None had previously used light therapy or
fluoxetine. No subjects were currently taking other psychotropic medications,
and none had engaged in formal psychotherapy for three months prior to the
study or while participating in it.
The researchers randomly assigned 48 eligible subjects to receive active
light therapy plus placebo capsules, and 48 to receive placebo light therapy
Subjects on active light therapy received daily exposure to 10,000 lux
light for 30 minutes as soon as possible after they awakened— the
now-standard treatment. The placebo light therapy utilized dim light of only
100 lux on the same schedule. To minimize expectation bias, researchers told
patients that the study aimed to examine different wavelengths of light
without mentioning intensities.
Subjects receiving active medication took 20 mg of fluoxetine in a single
daily dose between 7 a.m. and 8 a.m. The identical placebo capsule taken at
the same time of day had an inert filler.
Board-certified psychiatrists, blinded to treatment assignments, assessed
patient response using a variety of Hamilton depression scales. For the study,
the researchers defined clinical response as a 50 percent or greater reduction
in baseline in 24-item Hamilton depression scale scores at the last visit.
They defined clinical remission as a clinical response plus a score of 8 or
Researchers monitored adverse effects using a self-rated patient scale that
assesses frequency and severity of 32 adverse events. This scale provides a
broader and more systematic picture than spontaneous self-reports.
Forty subjects in the active light treatment group and 40 in the active
fluoxetine treatment group completed the study, with the majority improving in
all measures over time. The response and remission rates for both active
treatments were similar in magnitude to those reported in other
Rates of many adverse events, despite intensive reporting, were lower than
5 percent for both light and fluoxetine treatment.
At baseline, the researchers found no differences in expectations for light
or drug between subjects assigned to either group. Overall, subjects had
higher expectations for light over drug, although not for one light condition
over the other.
A grant from the Canadian Institutes of Health Research (CIHR) and a
CIHR/Wyeth postdoctoral fellowship to one of the researchers funded the study.
Up-lift Technologies supplied the light boxes.
"The Can-SAD Study: A Randomized Controlled Trial of the
Effectiveness of Light Therapy and Fluoxetine in Patients With Winter Seasonal
Affective Disorder" is posted at<http://ajp.psychiatryonline.org/cgi/content/full/163/5/805>.▪