For those of us living in the northern hemisphere, the winter solstice and least amount of daylight is fast approaching, as is the risk of Seasonal Affective Disorder (SAD).

An estimated¹ 20 percent of Americans are affected by SAD each winter, suffering from the blues, fatigue, and in some cases, more serious depression as sunlight grows scarce.

Worldwide, it strikes about 1 in 20.² What differentiates SAD from regular depression is that a full remission occurs in the spring and summer months. The fact that SAD occurs when sunlight is at a minimum is not a coincidence.

Your health and mood are intricately tied to exposure to sunlight. For example, your serotonin levels (the hormone typically associated with elevating your mood) rise when you’re exposed to bright light.

Your melatonin level also rises and falls (inversely) with light and darkness. When it’s dark, your melatonin levels increase, which is why you may feel tired when the sun starts to set (and in the heart of winter, this may be at as early as 4 p.m.).

Scientists generally recommend full-spectrum light therapy over SSRIs like Prozac or Zoloft for this condition, as it has virtually no side effects and is far less expensive than prescription drugs. And, according to recent research, light therapy may be preferable even for major depression.

Light Therapy for Non-Seasonal Depression

The study^3,4,5,6 set out to compare the effectiveness of light therapy, alone and in conjunction with the antidepressant fluoxetine (sold under the brand name Prozac).

The eight-week-long trial included 122 adults between the ages of 19 and 60, who were diagnosed with moderate to severe depression. The participants were divided into four groups, receiving:

       1. Light therapy (30 minutes per day upon waking using a 10,000 lux Carex brand Day-Light device, classic model) plus a placebo pill
       2. Prozac (20 mg/day) plus a deactivated ion generator serving as a placebo light device
       3. Light therapy plus Prozac
       4. Placebo light device plus placebo pill (control group)

In conclusion, the study found that the combination of light therapy and Prozac was the most effective — but light therapy-only came in close second, followed by placebo. That’s right, the drug treatment was the least effective of all, and LESS effective than placebo!

The mean changes in the Montgomery-Åsberg Depression Rating Scale (MADRS) from baseline to the eight-week end point was 16.9 for the combination therapy (active light and drug therapy), and 13.4 for light therapy alone.

Meanwhile, as noted by the authors:

“The combination and light monotherapy were significantly superior to placebo in the MADRS change score, but fluoxetine monotherapy was not superior to placebo.” [Emphasis mine]