[Butterfly_Faerie]

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TREATMENT OF SAD

LIGHT THERAPY

Light therapy (previously known as phototherapy) is recognized as a safe and effective treatment for SAD. More than 3 dozen controlled studies have shown efficacy of light therapy with response rates of 60% to 90%. The most widely studied protocol is 2500 lux fluorescent light for 2 hours per day, although studies of higher intensity light have shown that 10,000 lux light for 30 minutes per day gives similar response rates. Lux is a unit of illumination intensity that corrects for the photopic spectral sensitivity of the human eye. For comparison, indoor evening room light is usually less than 100 lux, a brightly-lit office is less than 500 lux, a cloudy, gray winter day is around 4,000 lux, and bright sunshine can be 50,000 to 100,000 lux or more.

Although light therapy is regarded to be clinically effective, there are still some critiques about the evidence for its efficacy. Like other non-pharmacologic treatments, the studies are not funded by multinational companies, and so sample sizes tend to be small (usually less than 20 patients per condition) and the duration of treatment short (usually 1 to 2 weeks). There is also difficulty in designing a suitable placebo condition. Since the light cannot be “blinded”, some deception is usually required to control for non-specific effects of treatment and biases inherent in expectations of response. Not surprisingly, given the small sample sizes, some studies have not found superiority of bright light over putative placebo conditions. Other studies have not found that bright light is more effective than dim light of intensity found in ordinary indoor room light. In these studies, the possibility of statistical Type II errors (i.e., missing a true effect) was high.

Two multi-year, large-sample, placebo-controlled studies were recently reported that may finally answer the efficacy question. Both showed significant effects of the active bright light condition against plausible placebo controls. Additionally, a recent meta-analysis (where many similar studies are analyzed together using standardized effect sizes) also showed significant effects of bright light over dim or no light controls. Together, these studies should provide sufficient confirmatory evidence that light therapy does have significant clinical benefit over placebo in SAD.

Various studies have investigated clinical parameters of light therapy including intensity of light, wavelength of light, duration of daily exposure, and timing of light exposure within the day. Results of this research are summarized by current clinical guidelines for the use of light therapy . The protocol used in our clinic is exposure to 10,000 lux cool-white light produced by a fluorescent light box, fitted with a ultraviolet filter, for 30 to 45 minutes daily. Light therapy is usually administered in the early morning upon awakening (e.g., 7:00 a.m.) because many studies found that morning light exposure is superior to exposure at other times of the day. Patients use the light therapy for at least 2-3 weeks to determine response.

Patients usually obtain a light device (see below) and use light therapy at home, although some hospital and outpatient clinics have designed light therapy rooms for patient use. The onset of action of light therapy is rapid, with significant clinical improvement found in studies of 1 or 2 weeks duration. However, relapse usually occurs after a similar period once light therapy is discontinued. Therefore, most patients must use light therapy regularly during their symptomatic winter season, until the time of their usual spring/summer remission. Once patients have remitted, they can often experiment with individual dosing required to stay well. Thus, they may be able to maintain their response while reducing the daily time of exposure to 15 or 20 minutes, or by using the light box on weekdays only. In subsequent years, patients may be advised to begin light treatments in the early fall, before the onset of symptoms, thus avoiding any gradual or insidious impairment of function.

Several studies have shown that various atypical depressive symptoms predict positive response to light therapy. Similarly, the balance of melancholic symptoms (e.g., insomnia, appetite and weight loss) over atypical symptoms was correlated to poor response to light therapy.

Side effects to light therapy are generally mild and transient, and consist of headache, nausea, eyestrain, blurred vision, and feelings of edginess. Bright light exposure in the later evening may disrupt onset and maintenance of sleep. Like any effective antidepressant treatment, there is a risk of precipitating a hypomanic or manic episode with light therapy, and Bipolar I patients (those with a history of manic episodes) should be on mood-stabilizing medications if light therapy is used. Current dosing guidelines for intensity of light should not prove to be harmful to the eyes, and two long-term follow-up studies did not find any ophthalmologic changes with chronic use of light therapy. However, caution should be exercised when treating patients at higher risk of bright light induced eye damage, including patients with pre-existing retinal disease (e.g., retinitis pigmentosa), patients who are taking photosensitizing medications (e.g., lithium, antipsychotics, chloroquine), and elderly patients (due to the higher risk for senile macular degeneration, which may be asymptomatic). For those patients, an ophthalmologic examination is recommended before initiating light therapy, as well as regular follow-up monitoring.

Other light devices also have been studied for winter SAD. Three light therapy studies used a similar portable light visor. These studies, with large sample sizes and rigorous designs, found no differences between bright, medium, and dim intensity light, although the response rates of all conditions were similar to those of light box studies. Other head-mounted devices also have not demonstrated a dose-response relationship or a superior response compared to a putative placebo. It is possible that less light is required for therapeutic effect using light visors because of the close proximity of the light source to the eye. Physiologic studies using the light visor have shown that biological effects of light can be demonstrated with lower intensity light.

“Dawn simulator” devices are also marketed. These devices gradually increase the indirect light in a bedroom, while the patient is sleeping, to a final illumination of less than 500 lux, to simulate a summer dawn during the symptomatic winter. Preliminary studies of efficacy are promising, but not yet replicated, so dawn simulation remains an experimental treatment.

Light therapy has also been studied for nonseasonal depression, although not as extensively as for SAD. Several studies have shown positive effects with light therapy, although other studies have been negative. These studies generally had smaller effect sizes than light therapy studies of SAD, and were all of relatively short duration (1-4 weeks) compared to most antidepressant studies of nonseasonal depression. Thus, further replication or more definitive studies are required before light therapy can be endorsed as effective for nonseasonal depression.

OTHER TREATMENTS FOR SAD

Medications have not been studied in SAD as extensively as light therapy. Only 3 placebo-controlled studies have been reported for antidepressants in SAD. Selective serotonin reuptake inhibitors (SSRIs) are the best-studied medications, with multi-centre, placebo-controlled studies showing that fluoxetine and sertraline are effective in SAD. The fluoxetine study used a fixed 20 mg/day dose for 5 weeks. Although there was no significant difference in the raw depression scores, the clinical response rate of fluoxetine was superior to that of placebo (59% vs. 34%, respectively). The sertraline study used doses of 50 to 200 mg/day for 8 weeks. Sertraline was superior to placebo in both the depression scores and the clinical response rates (62% vs. 46%, respectively). A study of moclobemide (SAD and subsyndromal SAD patients) used low doses of 300 mg/day for only 3 weeks, and found no differences between drug and placebo.

Although not placebo-controlled, a 6-week comparison study of moclobemide versus fluoxetine, found no significant difference in response rate (64% vs. 44%, respectively). Other smaller controlled studies of tryptophan, d-fenfluramine, and hypericum suggest that these treatments, if the positive results can be replicated, may be effective for SAD.

A number of case series studies suggest that other antidepressants may also be beneficial for SAD, including bupropion, tranylcypromine and alprazolam.

Although psychological treatments like cognitive-behavioural therapy and interpersonal psychotherapy have been demonstrated to be effective in nonseasonal depression, there are as yet no studies of such treatments in SAD.

In summary, the first-line medication treatment for SAD is with SSRI medications such as fluoxetine and sertraline, followed possibly by moclobemide, then with other medications such as d-fenfluramine, tryptophan, bupropion and tranylcypromine.

HOW TO CHOOSE A TREATMENT FOR SAD

There are no published studies comparing the efficacy of light therapy versus medications for SAD. Thus, the choice of treatment for SAD requires individual risk/benefit assessment. There are more studies demonstrating efficacy of light therapy than there are of medications, but the studies of SSRI antidepressants are much larger than any individual light therapy study. Clinically, light therapy seems to work faster than antidepressants, and generally has fewer side effects. Many patients also prefer a non-pharmacologic treatment for their symptoms. For these patients, light therapy should be the first-line treatment of choice. However, compliance is an issue, since even the newer light therapy protocols mandate spending a half-hour per day or more using the light device. Many patients do not have the interest or motivation required to use light therapy effectively. For those patients, daily medication use is more convenient. For more severely depressed inpatients, antidepressant medications are indicated as first-line treatment, although light therapy is often useful as an adjunctive treatment.

Light boxes are now widely available commercially, at a cost of US$150 to US$350. Thus, the cost of a light box is approximately the same as one season of the newer antidepressant medications. For recurrent use, light therapy appears to be more cost-effective. However, insurance plans may not reimburse light boxes, while medications may be covered, and some patients may not be able to afford a light device. Many light device companies have rental programs or money-back guarantees so patients can have a trial of light therapy before purchasing a light device.

Some patients find that a combination of light therapy and medications works best for them, and that the dose of antidepressant can be reduced when light therapy is combined. Unfortunately, there are as yet no studies of combined use of light therapy and antidepressant medications.

CONCLUSION

.SAD is a common depressive condition that results in significant psychosocial dysfunction and disability. Primary care practitioners should be vigilant for the presenting features of SAD and subsyndromal SAD when seeing patients during the winter. SAD is a very treatable condition with a good prognosis. Sample sizes in light therapy studies have been limited, but the efficacy of light therapy in the treatment SAD has been established by multiple replications in independent laboratories around the world. Medications, notably SSRI antidepressants such as fluoxetine and sertraline, have also been demonstrated to be effective in SAD. Further research is required to elucidate the pathophysiology of SAD and light therapy, and the optimal treatment (light therapy, medications, psychotherapies, or a combination) for individual patients with SAD.

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<font color="blue">Good website, and links</font>http://www.psychiatry.ubc.ca/mood/sad/pcp_sad.htm#g

[lenjan]

Thanks, Sundance! This is great. :-) I appreciate your time and effort in digging this up.

Candy

[Butterfly_Faerie]

You are welcome, I came across this earlier while I was browsing some stuff, so I decided to post it here when I saw your post.

I hope that you find it helpful.

[Wants2Fly]

Dr. John has asked for blog posts, etc. See General Forum. This looks like Good info for that.