Will a Light Box Actually Help My Winter Depression?

Light Therapy, Part 2. Part 1 covers light therapy more broadly, including depression that isn’t seasonal. This part covers the protocol for seasonal depression and what changes if you have bipolar disorder.

“Every year it’s the same. By November I’m sleeping ten hours, eating everything, and still dragging. Does a light box actually do anything?”

For seasonal affective disorder, yes. Light therapy is one of the best-supported treatments we have for winter depression, and in the one large trial that put it head to head with an antidepressant, it did about as well. The catch is that it only works at the right dose and the right time of day, and a lot of what gets sold as a light box can’t deliver that dose. It’s one of the non-pharmacological recommendations I make every winter, and I follow it myself.

Is it seasonal depression or just winter?

Most people feel slower when the days get short. Seasonal affective disorder is a depressive episode that keeps a calendar; mood drops in fall or winter and lifts in spring or summer, year after year. Light tends to help most when that winter picture includes oversleeping and overeating.

I’d confirm that pattern with a clinician before buying anything. A nonseasonal depression that happens to start in October, or bipolar disorder, can look like “winter blues” at first, and bipolar disorder changes how light should be used.

What the evidence for light therapy in SAD shows

Light therapy has been tested in more than 100 clinical trials since the early 1980s, and The Carlat Psychiatry Report puts its effect size for winter depression at 0.5 to 0.8, which compares well with medication. Light also helps some depression that isn’t seasonal, which I covered in Part 1; this post sticks to the winter pattern.

The trial I point patients to is Can-SAD. Ninety-six people with winter depression got eight weeks of either a 10,000 lux light box for 30 minutes each morning plus a placebo pill, or fluoxetine (Prozac) 20 mg plus a dim placebo light. About two-thirds of each group responded, and remission rates were close (50% with light, 54% with fluoxetine). Light pulled ahead at week one, and fluoxetine caused more agitation, sleep disturbance, and palpitations. The limit is that there was no group with both a placebo pill and a placebo light, so the study shows the two were comparable, not how far either beat doing nothing.

One detail from that research matters at home. The dim light used as a placebo in trials is about as bright as an ordinary room; indoor light runs roughly 300 to 1,000 lux. A sunny window seat or a bright desk lamp can feel nice, but it isn’t the treatment.

How to use a light box for SAD

For this morning SAD protocol, use white light at 10,000 lux at your eyes. Lower-intensity boxes require longer sessions, so don’t substitute one minute for minute.

Use it soon after you wake up, at the same time every morning. I recommend keeping SAD treatment in the morning rather than making up a missed session late in the day. Light near bedtime can disturb sleep. If your sleep schedule makes morning treatment difficult, ask your clinician to help set the timing.

Start with 30 minutes. Most people end up needing 30 to 60. Some notice a change within a few days; most should be clearly better by about two weeks. If nothing has moved by days 10 to 14, check the timing and distance with your clinician and discuss increasing to 60 minutes.

The box should sit slightly above eye level and angle down toward you, roughly 30 to 45 degrees. Eyes open, but don’t stare into it; reading, eating, or working on a laptop is fine. Regular glasses are okay. Sunglasses, tinted, transition, or blue-blocking lenses defeat the purpose. Sit at the distance where your particular box delivers 10,000 lux, as specified by its manufacturer. That distance varies by device; there isn’t one number of inches that works for every box.

If your pattern is predictable, start about two weeks before your usual low, keep going through winter, and taper over about two weeks in spring. Missing a day or two is usually fine. Missed mornings, week after week, are the usual reason it “didn’t work,” far more often than the box itself.

If you have bipolar disorder

Winter depression is common in bipolar disorder, but light treatment needs a separate plan with your psychiatric clinician. Light can trigger hypomania, mania, or mixed symptoms. I treat it as an add-on to appropriate antimanic medication, not a replacement for it, and I favor a supervised midday approach.

The trial behind that approach is a 2018 randomized study in the American Journal of Psychiatry. Forty-six adults with bipolar I or II depression continued stable antimanic medication and received either 7,000 lux white light or dim red placebo light for six weeks. Sessions took place between noon and 2:30 pm, starting at 15 minutes a day and increasing by 15 minutes after each weekly assessment, toward 60 minutes by week four or until remission. Increases depended on tolerable side effects and no emerging hypomania. This was a 7,000 lux study protocol, not the 10,000 lux morning SAD routine above.

At weeks four through six, about 68% of the bright-light group met the study’s remission threshold, compared with 22% of the placebo group. No mood switches occurred, but the trial was small and carefully supervised. It excluded people with manic, hypomanic, or mixed episodes in the previous six months, rapid cycling in the previous year, and several other risks. Those results don’t make unsupervised light treatment safe for everyone with bipolar disorder.

A later small pilot trial also found improvement with light added to medication. For me, the practical point is to agree on the timing, intensity, and gradual increases with your clinician, with regular checks on mood and sleep.

If you feel irritable, unusually “up,” restless, or find you need less sleep, stop the light and call your clinician. Don’t restart or adjust the dose on your own.

Eyes, medications, and side effects

If you have glaucoma, cataracts, macular degeneration, or retinal disease (including diabetic eye disease), see your eye doctor first. Ask your prescriber or pharmacist to check your medication list before starting, especially if you take a medicine that can cause photosensitivity, such as the phenothiazine antipsychotic chlorpromazine, or if you have lupus. That risk depends on the specific medicine; it doesn’t apply equally to every antipsychotic. Use a box with a UV filter. Never use a sunlamp or a tanning lamp.

The common side effects are headache, eye strain, and mild nausea, usually early and usually better with a shorter session or sitting a bit farther back.

Don’t stop your psychiatric medications to use a light box. Your clinician can help decide whether light is an appropriate addition to an antidepressant or other treatment. It isn’t a reason to skip an evaluation. If you’re having thoughts of suicide, call or text 988 (in the US), or go to the nearest emergency room.

The light box I use, and the one I’d start with

I use the Alaska Northern Lights Aurora LightPad Mini, mostly because it’s portable and comes with me. To be fair about it, its face is small: about 7.5 by 5.25 inches, roughly 40 square inches. The Center for Environmental Therapeutics recommends a screen over 200 square inches, and the Carlat protocol asks for at least 12 by 15 inches. The maker rates it at 10,000 lux at 25 inches, but with a small face, small head movements can drop the dose you actually get. It fits my routine; it isn’t the standard pick.

If you’re buying one box for seasonal depression, the Carex Day-Light Classic Plus is the full-size choice I’d start with. It’s rated at 10,000 lux at 12 to 14 inches, has a screen of about 16 by 13 inches (around 208 square inches), filters UV, and is one of the brands Carlat names as reliable. Prices change often, so I’m not listing them.

Be skeptical of the cheapest lamps on big marketplaces; some only reach 10,000 lux a few inches from your face. CET’s guide to choosing a light box lays out the criteria.

I don’t earn anything from the products I recommend on this site, including either box here. The one exception is a Wispr Flow referral link on my Contact page.

This is general information, not personalized medical advice. Don’t start, stop, or change a treatment without talking to your own clinician, especially if you have bipolar disorder, eye disease, or take photosensitizing medications.

This article was written in my own words with the help of Wispr Flow, a voice-to-text tool I use for drafting.

References

1. Lam RW, Levitt AJ, Levitan RD, et al. The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder. American Journal of Psychiatry. 2006;163(5):805-812. doi:10.1176/ajp.2006.163.5.805. PubMed
2. Aiken C. A practical guide to light therapy. The Carlat Psychiatry Report. November 15, 2019. Link
3. Higgins EM. Pocket protocol for light therapy (reference table). The Carlat Psychiatry Report. 2021;19(10). PDF
4. Bright light therapy fact sheet. Medication Fact Book for Psychiatric Practice, 7th ed. Carlat Publishing. PDF
5. UBC Mood Disorders Centre. Procedure for using the 10,000 lux fluorescent light box. University of British Columbia. Link
6. Cuomo A, Carmellini P, Garo ML, et al. Effectiveness of light therapy as adjunctive treatment in bipolar depression: a pilot study. Journal of Affective Disorders. 2023;321:102-107. doi:10.1016/j.jad.2022.10.009. PubMed
7. Center for Environmental Therapeutics. How to select a light box. Link
8. Sit DK, McGowan J, Wiltrout C, et al. Adjunctive bright light therapy for bipolar depression: a randomized double-blind placebo-controlled trial. American Journal of Psychiatry. 2018;175(2):131-139. doi:10.1176/appi.ajp.2017.16101200. PubMed: randomized trial of midday light in bipolar depression
9. Chlorpromazine hydrochloride. Prescribing information. DailyMed: photosensitivity and ocular precautions