In healthy adult woman, does light therapy compared to a placebo impact seasonal affective disorder?

Lynn Bucher, Nikki Schenandore, Taylor Folk, Jenn Hulse & Jill JohnsonYork College of Pennsylvania

Introduction

METHODS

RESULTS Recommendations

SUMMARY

Seasonal Affective Disorder (SAD) affects 0.4%-2.7% of the general populations of the United States and Canada. SAD has been defined as a mood disorder consisting of recurrent episodes of depression that are congruent with a “seasonal pattern.” Winter depression is the most common type, and is manifested by symptoms of depression during the fall and winter seasons followed by a full remission in spring and summer. Symptoms associated with SAD include: Depressed mood; Lack of energy; Hypersomnia; Carbohydrate craving with subsequent weight gain. Impairment, in those suffering from SAD, in the areas of occupational and social functioning has also been identified. The primary treatment for SAD is light therapy which is exposing the sufferer to artificial bright light during the symptomatic months.7 We chose to explore the efficacy of light therapy as the optimal treatment for SAD. Our PICO question is: In healthy adult women, does light therapy, compared to a placebo, impact Seasonal Affect Disorder.

A total of 35 research articles were found and reviewed using PubMed, Google Scholar, OVID, and Chochrane databases. Of the 35 articles found, 25 of them were excluded because they did not have significant data, weren't experimental, or did not meet the criteria for our PICO question. The search terms that we used included light therapy, seasonal affective disorder (SAD), seasonal mood disorder, depression, randomized controlled trial, placebo, or they were references found in other research articles that we reviewed. We limited our search to articles that were written in 2001 and later.

• Since there are few studies testing light therapy using a placebo condition, further research is needed to create a placebo for visible light treatment.5,8

• There is a need to test the effects of light therapy based on a patient’s individual circadian rhythm to determine the appropriate time to administer the light therapy, rather than just being administered in the morning.1,7

• A strong design and methodology, by the use of an inactive control group, can reduce the occurrence of uncommon events such as light sensitivity or sight problems.1

• Standardizing treatment time can decrease side effects and lead to more positive outcomes.4

We conclude that light therapy compared to placebo therapies (pharmalogical, cognitive, negative ion, transcranial bright light) is an effective treatment for healthy adult women suffering from seasonal affective disorder. A minimum of four weeks of bright light treatment has been proved to significantly decrease depressive symptoms associated with seasonal affective disorder when compared to other placebos.

EVIDENCE SUMMARY TABLE Level of

Evidence # of

Studies Summary of Findings Quality

Level I: Experimental (randomized controlled trial- RCT) or meta-analysis of RCTs

7

Early morning light exposure resulted in greater remission of SAD symptoms based on the SIGH-SAD, compared to a placebo.1

With 4 weeks of light therapy treatment, patients experienced a significant decrease in depressive symptoms and higher rates of remission.3

Patients receiving Bright White light therapy showed significant decreases in SAD symptoms according to the SIGH-SAD scale.4

Effects of bright light therapy are comparable to effects found in many antidepressant pharmacotherapy with a significant reduction in symptoms of depression.5

Although bright light therapy improves symptoms in the first week of treatment, there was no significant difference between light therapy and antidepressant therapy after 6 weeks.7

Ten-day bright light treatment in a light therapy room reduced self-reported depression in subjects with winter depressive mood.9

Light therapy combined with cognitive-behavioral therapy may be the most optimal treatment for SAD.10

B1

B3

A4

B5

B7

B9

C10

Level II: Quasi Experimental

3

Bright light in the workplace is effective in improving mood, energy, alertness, productivity, and the quality of awakening. 2

After receiving transcranial bright light therapy for 4 weeks, patients experienced a significant decrease in depression and anxiety related to SAD on both a self-rated and psychiatrist rated scale.6

Low-intensity blue white light is highly effective and equal to standard bright light in improving symptoms of mood, sleep quality, and energy levels.8

C2

B6

B8