Seasonal Affective Disorder Treatment: Light Therapy, Bupropion and CBT-SAD

Seasonal affective disorder (SAD) has three well-studied treatments: bright light therapy, a version of cognitive behavioral therapy built for SAD (CBT-SAD), and antidepressants. Extended-release bupropion is FDA-approved to prevent seasonal depressive episodes in people with a diagnosis of SAD. In a large head-to-head trial, light therapy and CBT-SAD worked equally well during an episode, and CBT-SAD was followed by fewer recurrences two winters later.

Which one fits depends on how severe your symptoms are, whether you have a history of bipolar disorder, eye conditions or seizures, how much time you can give each morning, and whether you want to prevent the next winter or treat the one you are in. Because SAD returns on a predictable schedule, timing is part of the treatment plan.

Is it SAD, the winter blues, or something else?

SAD is a form of depression with a recurring seasonal pattern. In the more common winter pattern, symptoms start in late fall or early winter and lift in spring and summer; a less common summer pattern also exists. According to the National Institute of Mental Health (NIMH), symptoms last about 4 to 5 months of the year.

For a diagnosis, NIMH lists three requirements: depressive symptoms (or the specific winter or summer symptoms), episodes during a specific season for at least 2 consecutive years, and seasonal episodes that are more frequent than episodes at other times of year. Winter-pattern symptoms can include oversleeping, overeating with carbohydrate craving and weight gain, and social withdrawal.

NIMH distinguishes SAD from "holiday blues," which follow calendar stresses rather than daylight changes. It also notes that SAD is more common in people with depression or bipolar disorder, especially bipolar II. That last point shapes treatment, because light and antidepressants both need extra care in bipolar disorder. If you have ever had a period of unusually high energy, little need for sleep and racing thoughts, mention it; the site's article on bipolar disorder vs depression explains why it matters.

The main options at a glance

Light therapy: how it is done and who should be careful

NIMH describes the standard approach: a very bright light box of 10,000 lux, about 30 to 45 minutes every day, usually first thing in the morning, from fall to spring. The box is about 20 times brighter than ordinary indoor light and filters out ultraviolet light. In the largest trial comparing light with CBT-SAD, light was started at 30 minutes each morning and then adjusted according to response and side effects.

A few practical points make a difference:

• Consistency matters more than intensity on any single day. Pick a time you can keep, such as breakfast or the first email check.
• The box is meant to be in your field of view, not stared at. Follow the manufacturer's distance instructions, because brightness falls off quickly with distance.
• Products marketed as "SAD lamps" vary. Ask your clinician what specifications to look for rather than relying on packaging claims.
• Track your mood and sleep weekly so you and your clinician can tell whether the timing or duration should change.

Light therapy is a safe treatment for most people, but NIMH notes that people with certain eye diseases, or who take medicines that increase sensitivity to light, may need an alternative or medical supervision. Ask an eye doctor first if you have a retinal condition.

Bipolar disorder and light

Light therapy is also studied as an add-on treatment for bipolar depression. A 2020 meta-analysis of 7 randomized trials with 259 patients found improvement in depressive symptoms and no difference in mood switches between active and control light, but the authors called the evidence positive but not conclusive and noted small samples and short treatment. Short, small trials cannot rule out a rare switch into hypomania or mania. If you have bipolar disorder, use light therapy only as part of a plan with your prescriber, who can adjust timing and watch for early warning signs.

CBT-SAD: therapy designed for the season

CBT-SAD adapts cognitive behavioral therapy to seasonal depression. NIMH describes it as two weekly group sessions for 6 weeks. It works on two fronts: replacing negative thoughts tied to the season, such as dread about darkness, and behavioral activation, which means scheduling pleasant and engaging indoor or outdoor activities to counter the winter loss of interest. The second piece overlaps with behavioral activation for depression, which is covered in its own article.

What the head-to-head trial found

Kelly Rohan and colleagues randomized 177 adults with recurrent winter depression to 6 weeks of CBT-SAD or light therapy. CBT-SAD was delivered as 12 group sessions, two 90-minute sessions a week, by doctoral-level psychologists. Depression improved comparably with both treatments, and remission rates on the clinician-rated scale were nearly identical: 47.6% with CBT-SAD and 47.2% with light therapy.

The difference showed up later. The treatments did not differ during the first winter of follow-up, but at the second winter, recurrence was 27.3% after CBT-SAD compared with 45.6% after light therapy. One possible explanation, which the trial did not test directly, is that light therapy helps while you keep using it, while CBT-SAD teaches skills you carry forward. NIMH summarizes the same pattern: both treatments were equally effective, light sometimes worked a little faster, and CBT's benefits seemed to last longer.

Group CBT-SAD is not offered everywhere. Individual CBT from a therapist who knows behavioral activation and cognitive work for depression can cover similar ground. The site's overview of CBT in Brooklyn explains the general approach.

Bupropion XL: the FDA-approved prevention option

The Wellbutrin XL label lists a specific indication: prevention of seasonal major depressive episodes in patients with a diagnosis of SAD. The approval rests on 3 placebo-controlled trials in adults with a history of autumn-winter depression.

How it is used

The label says to start in the autumn, before symptoms begin, continue through winter, and taper and stop in early spring. The label's starting dose is 150 mg once daily, which may be raised to 300 mg after 7 days; people on 300 mg are stepped down to 150 mg before stopping. Timing and dose are set by your prescriber, based on when your episodes usually start.

How much it helps

Across the three trials, 84.3% of people taking bupropion stayed free of a depressive episode through the season, compared with 72.0% on placebo. Most people on placebo also stayed well, which is worth noticing. A 2019 Cochrane review concluded bupropion XL is effective for preventing SAD recurrence, but that even in a high-risk group, three out of four people will not benefit from preventive treatment and will still be exposed to possible harms. The reviewers advised that the decision should rest strongly on patient preference.

Who should not take it

• People with a seizure disorder, or with conditions that raise seizure risk, such as abrupt withdrawal from alcohol or benzodiazepines.
• People with a current or past diagnosis of bulimia or anorexia nervosa, because of a higher seizure rate.
• Anyone with bipolar disorder unless the prescriber has screened for it and is monitoring; the label warns about activation of mania or hypomania.

In the SAD trials, some people developed higher blood pressure: hypertension was reported in 2% of the bupropion group and none of the placebo group. Like every antidepressant, bupropion carries a boxed warning about suicidal thoughts and behaviors in young people. For a fuller picture of how bupropion compares with SSRIs and SNRIs, see SSRI, SNRI or bupropion.

If you are thinking about suicide or are in crisis, call or text 988 (the 988 Suicide & Crisis Lifeline) or go to the nearest emergency room.

Other antidepressants and vitamin D

SSRIs are sometimes used for SAD, as they are for depression in general. NIMH notes that antidepressants usually take 4 to 8 weeks to work, and that sleep, appetite and concentration often improve before mood. Using an SSRI for SAD is treating depression with a seasonal pattern; the SAD prevention indication discussed above is on the extended-release bupropion label. The broader menu, including therapy and neuromodulation, is in depression treatment options compared.

Vitamin D is often suggested because levels drop in winter. NIMH reports mixed results: some studies found it as effective as light therapy, while others found no effect. A blood test can tell you whether you are actually low; the site's guide on whether to test your vitamin D walks through that decision.

Prevention: when to start before fall

Because SAD tends to arrive at the same time each year, NIMH notes that people with a history of it may benefit from starting treatment before fall (or before spring for the summer pattern), although few studies have tested prevention directly. Cochrane reviews of light therapy and of psychological therapy for prevention found too little evidence to draw conclusions. Extended-release bupropion is the option here with an FDA-approved prevention indication.

A practical calendar to discuss with your clinician:

1. Late summer: look back at when your symptoms usually start. Write down the month and the first signs (oversleeping, cravings, pulling away from friends).
2. Early fall: book a visit before that window. Decide together whether to start light therapy, schedule CBT-SAD, start bupropion XL, or watch closely.
3. Through winter: track mood and sleep weekly. Agree in advance what change would prompt a call.
4. Early spring: plan any taper with your prescriber; do not stop medication on your own.

The site's page on fall and winter mental health covers sleep, holiday stress and grief during the dark months.

Choosing among the options

Sleep problems often travel with SAD. If insomnia rather than oversleeping is your main problem, insomnia treatment options may help you sort out what to treat first.

Questions to ask your clinician

• Do my symptoms fit a seasonal pattern, or is this depression that happens to be worse in winter?
• Is there anything in my history, such as bipolar symptoms, eye disease, seizures or an eating disorder, that rules out an option?
• If I use a light box, what timing and duration should I start with, and when should we adjust?
• Would CBT-SAD or individual CBT be available to me, and how many sessions are typical?
• If I start bupropion XL, when should I begin this year, and how will we taper in spring?

How Dr. Lewis's practice can help

The practice's team includes psychiatrists, psychiatric nurse practitioners and psychotherapists, and its services include psychiatric evaluation, medication management, psychotherapy including CBT, lab testing, and nutrition and lifestyle psychiatry. If winter depression is a pattern for you, a free discovery call by phone or text is a way to ask about care options, scheduling and insurance before your usual start month. Individual clinical care starts with the Patient Interest Form. The practice is out of network with all insurance plans; if you need in-network care, ask the team on the discovery call about options. The Choosing Psychiatric Care guide compares other starting points.

Frequently asked questions

Can I use a light box without seeing a doctor?

Many people do, but it is safer to check with a clinician first if you have an eye condition, take medicines that increase light sensitivity, or have any history of bipolar disorder. A clinician can also confirm that what you have is SAD and not another kind of depression.

Does a dawn simulator or a sunny walk count as light therapy?

The standard approach NIMH describes uses a 10,000-lux box for a set time each morning. Outdoor light and dawn simulators may help some people, but they are not the same as that standard protocol. Ask your clinician whether they fit your plan.

Is bupropion XL the only medicine for SAD?

Extended-release bupropion is the medicine FDA-approved specifically to prevent seasonal depressive episodes in people with SAD. Other antidepressants, often SSRIs, are used to treat depression with a seasonal pattern.

What about summer-pattern SAD?

It is less common and less studied. NIMH notes there are no treatments specific to summer-pattern SAD; psychotherapy and antidepressants used for depression in general are the usual options.

Will I need treatment every winter?

Not necessarily. Light therapy is typically used daily from fall to spring, so people who rely on it usually restart it each fall. CBT-SAD teaches skills that may carry over, and in one trial was followed by fewer recurrences at the second winter.

Can I take vitamin D instead of light therapy?

Studies of vitamin D for SAD have mixed results. A blood test can show whether you are low. Treating a true deficiency is reasonable, but it is not a proven substitute for light therapy, CBT-SAD or medication.

Sources

1. Seasonal Affective Disorder. National Institute of Mental Health (NIH Publication No. 23-MH-8138), 2023. nimh.nih.gov
2. WELLBUTRIN XL (bupropion hydrochloride extended-release tablets), prescribing information. U.S. National Library of Medicine DailyMed, 2025. dailymed.nlm.nih.gov
3. Randomized Trial of Cognitive-Behavioral Therapy Versus Light Therapy for Seasonal Affective Disorder: Acute Outcomes. American Journal of Psychiatry (Rohan KJ, et al.), 2015. pubmed.ncbi.nlm.nih.gov
4. Outcomes One and Two Winters Following Cognitive-Behavioral Therapy or Light Therapy for Seasonal Affective Disorder. American Journal of Psychiatry (Rohan KJ, et al.), 2016. pubmed.ncbi.nlm.nih.gov
5. Second-generation antidepressants for preventing seasonal affective disorder in adults. Cochrane Database of Systematic Reviews (Gartlehner G, et al.), 2019. pubmed.ncbi.nlm.nih.gov
6. Light therapy for preventing seasonal affective disorder; Psychological therapies for preventing seasonal affective disorder. Cochrane Database of Systematic Reviews (Nussbaumer-Streit B, et al.; Forneris CA, et al.), 2019. pubmed.ncbi.nlm.nih.gov
7. Light Therapy for Patients With Bipolar Depression: Systematic Review and Meta-Analysis of Randomized Controlled Trials. Canadian Journal of Psychiatry (Lam RW, et al.), 2020. pubmed.ncbi.nlm.nih.gov

Educational information, not medical, tax or legal advice. Decisions about diagnosis, medication and treatment belong with a clinician who knows your history.