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Which course is recommended
for individual patients with SAD depends on both the severity of symptoms
and patient preference. Light treatment units are not usually covered
by provincial medical plans so that the cost of treatment may also be
a factor in considering which approach is best for a patient with SAD.
Pharmacotherapy
Traditional antidepressants, notably the TCAs, tend to be poorly tolerated
by patients with SAD. Because TCAs may contribute to weight gain and somnolence,
they may accentuate features of SAD, including weight gain and an excessive
need for sleep. The SSRIs or the newer cyclic antidepressants - nefazodone
(Serzone), venlafaxine (Effexor), or bupropion (Wellbutrin) - have fewer
side effects and are usually considered first in the treatment of SAD.
Although there have
been no studies evaluating the effectiveness of combination light therapy
and antidepressant medications, combination therapy is quite common in
clinical practice and it may be considered.
Seasonal Affective Disorder3 |
| Level
of Evidence |
Place
in Therapy |
Medication |
Usual
Daily Dose1 |
Cost
per
Day2 |
| Level
I Evidence and generally tolerable side effect/safety profile. |
1st
choice |
Light
therapy4
is FIRST CHOICE when:
1.
episode is not severe and patient is not suicidal
2. medical reasons exist to avoied antidepressants
3. previous response was positive
4. preferred by patient
Light
therapy using commercially available light boxes should be considered
for well documented seasonal non-psychoitic winter depressive epsodes
in patients with recurrent major depressive disorder or mild seasonal
episodes. The usual protocol for light therapy invovles the use
of a fluorescent light box rated at 10,000 lux for 30-45 minutes
per day, in the early morning between 6:00 and 8:00 a.m. Response
is seen usually in 1-3 weeks but may occur within 4 to 7 days.
|
FLUOXETINE
(Prozac) |
20-40
mg |
$1.08-2.16 |
| Level
II evidence or Level I evidence but less tolerable side effect/safety
profile. |
2nd
choice |
MOCLOBEMIDE
(Manerix) |
450-600
mg |
$1.22-2.28 |
| L-tryptophan |
2-8
g |
$2.85-11.40 |
|
NOTE:
Non-responding patients should be switched to an alternative 1st
choice agent prior to attempting a 2nd choice antidepressant.
|
|
1.
Usual daily doses are provided unless otherwise stated. Consult
the drug monograph for details on age and condition specific dosing.
2.
Approximate costs were derived from the ODB formulary (#36) or manufacturers'
price lists and do not include professional fees or markups.
3.
Furher guidelines on SAD are available. See Canadian Consensus Guidelines
for the Treatment of Seasonal Affective Disorder: A Summary of the
Report of the Canadian Consensus Group on SAD. Lam RW & Levitt
AJ (Eds). The Canadian Journal of Diagnosis Supplement Oct 1998;
p. 1-15.
4.
Light therapy or medication treatment is usually continued throughtout
the winter, and discontinued at the time of the usual spring/summer
remission. For more information on light therapy and light box suppliers,
contact your nearest university-affiliated Department of Psychiatry.
From: CANMAT
- Guidelines for the Diagnosis and Pharmacological Treatment of
Depression (1st Edition Rev., 1999) Page 22.
Back
to Treating Depressive Disorders
Back
to Managing Depressive Disorders - (Selections from:
CANMAT - Guidelines for the Diagnosis and Pharmacological Treatment
of Depression [1st Edition Rev., 1999])
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Light Therapy
Light therapy involves exposure to intense levels of light under controlled
conditions. There are various types of apparatus available, ranging from
a light box equipped with fluorescent bulbs and a diffusing screen, to
headsets and glasses of various designs. Treatment sessions vary in length
with the intensity of light used (15 minutes to 3 hours, once or twice
a day, using illumination ranging from 2,500 to 10,000 lux). The intensity
of light therapy is 5 to 20 times higher than typical indoor illumination.
The timing of light therapy is an important factor, and varies from person
to person; some people respond best to early morning therapy, while others
do better with evening therapy.
The reason for the
apparent effectiveness of light therapy has not been completely defined,
although there are a number of theories. Studies have shown that light
has a biological effect on brain hormones and functioning. People with
SAD may have a disturbance in the biological clock in the brain, which
regulates hormones, mood and sleep. The intense light experienced in light
therapy may help to restore normal function. As in other depressive disorders,
changes in the function of the neurotransmitters serotonin and dopamine
may be disturbed in SAD, and these imbalances may be corrected by light
therapy as with antidepressant medications. It is important to counsel
patients to keep their eyes open during the treatment, because the therapeutic
effect from light is gained by its absorption through the eyes, not the
skin.
A meta-analysis reviewing
various light studies (up to 1989) found that light therapy was effective
in about half of patients, provided it was given in the morning. Patients
with milder symptoms are also more likely to do well with light therapy
than those whose symptoms are more severe.
When effective, light
therapy works quite quickly, with about 70% of responders improving within
the first week. Most clinicians recommend a two-week trial of light therapy,
with treatment beginning as soon as possible after the patient wakes up.
Because depressive symptoms have been shown to return within about a week
if light therapy is discontinued, patients are advised to maintain a consistent
daily schedule throughout the winter months.
If symptoms do not
improve after two weeks of light therapy, it is unlikely they will respond
and another approach should be tried.
Side effects are uncommon,
but eye strain, headaches, insomnia, irritability, dry eyes and rarely,
hypomania have been reported.
Preventive Measures
When patients have regular episodes of winter depression, there are good
reasons why treatment should be initiated between September and November,
before symptoms begin. Most patients prefer to avoid the recurrent episode
entirely and are motivated to do so. If patients wish to delay treatment
until symptoms develop, they should know that it is harder to bring symptoms
under control if they wait, and that by starting treatment early, they
are likely to remain well throughout the winter. In addition, patients
need to counter the illness with lifestyle measures.
Because carbohydrate
cravings are common in SAD, patients need to be advised to select simple
carbohydrates and pay attention to their daily caloric intake to minimize
weight gain. Regular exercise also mitigates against weight gain and improves
both self-esteem and sleep quality. Patients should also be encouraged
to spend more time outside where they will be exposed to natural light.
A regular sleep schedule
with some restriction on the amount of sleep patients allow themselves
helps guard against what can be large fluctuations between normal sleep
patterns and those that develop as a result of SAD.
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