Seasonal affective disorder is major depression with a recurring seasonal pattern, usually fall and winter. It is treated with morning bright light therapy at 10,000 lux, antidepressants such as bupropion XL (FDA-approved to prevent seasonal episodes) or SSRIs, and CBT tailored to seasonal depression. Most people improve within two to four weeks of starting treatment, and starting before symptoms begin prevents many episodes.
Florida and South Carolina get more sunlight than Boston or Seattle, but SAD still occurs here, especially among people who relocated from the north, who work indoors, or who have a strong personal or family history of depression. At Stedfast Psychiatry we confirm the seasonal pattern, rule out other causes, and treat with the three approaches that have the best evidence: bright light therapy, medication, and cognitive behavioral therapy adapted for seasonal depression.
Symptoms of SAD
- Depressed mood that begins at the same time each year, usually late fall
- Sleeping more than usual and still feeling tired
- Craving carbohydrates and sweets, with weight gain
- Low energy and heaviness in the arms and legs
- Loss of interest in activities and social withdrawal
- Difficulty concentrating
- Irritability or feelings of hopelessness
- Full recovery in spring or summer, sometimes with a brief period of elevated mood
- In summer-pattern SAD: insomnia, poor appetite, weight loss and agitation
Causes and risk factors
The leading explanation is that shorter days disrupt the body's circadian clock. Reduced morning light delays the internal rhythm relative to the sleep-wake schedule, and that phase delay is associated with depressive symptoms. Serotonin activity drops in winter in some people, melatonin secretion lengthens, and genetic variants that affect light sensitivity in the retina appear more often in people with SAD. Vitamin D deficiency has been proposed but the evidence that supplementing it treats SAD is weak.
Risk is higher in women, in people with a family history of depression or bipolar disorder, in younger adults, and in those who moved from a northern climate. Shift work, windowless offices and spending the daytime indoors can produce a winter pattern even in a sunny state.
About 5 percent of US adults experience seasonal affective disorder, and symptoms typically last about 40 percent of the year.
Source: American Psychiatric Association
Bupropion XL is the only medication with FDA approval for the prevention of seasonal major depressive episodes, approved in 2006.
Source: U.S. Food and Drug Administration
In a randomized trial, CBT tailored for SAD matched bright light therapy during the first winter and produced significantly fewer recurrences two winters later (27 percent versus 46 percent).
Source: Rohan et al., American Journal of Psychiatry, 2015 and 2016
Women are about four times more likely than men to be diagnosed with SAD, and risk is higher in younger adults.
Source: National Institute of Mental Health
How we diagnose it at Stedfast Psychiatry
SAD is a specifier for major depressive disorder or bipolar disorder, not a separate illness, so the evaluation starts by confirming that full depressive episodes are present. Your clinician at Stedfast Psychiatry takes a year-by-year history of mood, sleep and appetite, looking for at least two consecutive years in which depression began and ended at the same times of year and non-seasonal episodes were absent or rare. We use the PHQ-9 and the Seasonal Pattern Assessment Questionnaire, and we ask carefully about spring or summer periods of unusually high energy, because a seasonal pattern can be the first clue to bipolar disorder, which changes treatment. Hypothyroidism, anemia, sleep apnea and low vitamin D can mimic winter fatigue, so we check TSH, a complete blood count and vitamin D when the history suggests it, and we refer for a sleep study if snoring and daytime sleepiness are prominent.
Treatment options
Bright light therapy
Light therapy is a first-line treatment with evidence comparable to antidepressants for winter-pattern SAD. The standard protocol is a 10,000 lux light box positioned at eye level and about 16 to 24 inches away, used for 20 to 30 minutes within an hour of waking, every morning through the dark months. Improvement often begins within one to two weeks. We help you choose a device that filters ultraviolet light, set the timing to match your schedule, and watch for overactivation, headache or eye strain. People with bipolar disorder use light therapy only with a mood stabilizer in place, and anyone with retinal disease should check with an eye doctor first. Starting light therapy in early fall, before symptoms arrive, works better than waiting.
Medication management
Bupropion XL is the only antidepressant FDA-approved for the prevention of seasonal major depressive episodes, approved in 2006. Started in early fall and continued through spring, it reduces the chance of a winter episode, and it tends not to cause the weight gain or sexual side effects that bother some people on SSRIs. SSRIs such as sertraline, fluoxetine and escitalopram are effective once an episode has started and are a reasonable choice if you have non-seasonal depression or anxiety too. We expect an initial lift in energy and sleep within two to three weeks and full response by six to eight weeks, and we typically taper medication in late spring if your pattern is strictly seasonal.
Psychotherapy
CBT adapted for seasonal depression, developed and tested by Kelly Rohan's group at the University of Vermont, targets the specific thoughts and habits of winter: hibernating, dropping activities, dreading the dark months. In a head-to-head trial it matched light therapy in the first winter and produced fewer recurrences the following winter, likely because the skills remain after the light box is put away. A typical course is six weeks of group or individual sessions in early fall. Our therapists deliver it in person and by video.
What to expect
Your first visit is a full psychiatric evaluation lasting about an hour, in person or by video. If a seasonal pattern is confirmed, you leave with a plan that usually combines two of the three main treatments and a date to start them next fall if you are seen off-season. Follow-ups are at two to four weeks while treatment is being adjusted, then monthly through the season. Most SAD care works well by telehealth, which suits people who do not want to drive to appointments when energy is low. We check your PHQ-9 at each visit and plan the taper for spring.
When to seek help
Make an appointment if you notice the same slump arriving each fall, if you are sleeping and eating far more than usual for weeks at a time, or if winter leaves you unable to work or connect with people. If depression brings thoughts of death or suicide at any time of year, call or text 988, go to the nearest emergency room, or call 911 if you are in immediate danger. Seasonal depression can be as severe as any other depression, and it responds just as well to treatment.
Winter pattern and summer pattern
Winter-pattern SAD accounts for the large majority of cases. Its signature is atypical depression: oversleeping, overeating with a pull toward carbohydrates, weight gain and a heavy, leaden fatigue. Summer-pattern SAD is less common and looks different, with insomnia, poor appetite, weight loss, agitation and sometimes anxiety that peaks in the hottest months. The summer pattern responds to standard antidepressants and to strategies that reduce heat and light exposure in the evening, such as air conditioning, darkened bedrooms and keeping a cool, regular sleep schedule. Light therapy is not used for the summer pattern.
Subsyndromal SAD, or the winter blues
Many more people have a milder version that does not meet criteria for major depression: lower energy, more sleep and less motivation from November to February without the full impairment of a depressive episode. This still responds to morning light, regular outdoor time and the behavioral strategies from CBT for SAD, and treating it early may prevent progression to a full episode in people with a family history of depression.
Ruling out look-alikes
Several conditions produce winter fatigue without being depression. Hypothyroidism causes tiredness, weight gain and low mood and is detected with a TSH. Obstructive sleep apnea causes oversleeping and poor concentration and is more common in people who gain weight in winter. Anemia and vitamin B12 deficiency cause fatigue and are easy to test for. Non-seasonal major depression that happens to start in fall is distinguished by its failure to remit in spring. And, as noted above, a spring high after a winter low raises the question of bipolar disorder.
Daily habits that reduce winter symptoms
Morning outdoor light is free and potent: even an overcast winter morning in Florida delivers far more light than indoor lighting. A 20 to 30 minute walk soon after waking combines light exposure with exercise, which has its own antidepressant effect. Keeping a consistent wake time, including weekends, anchors the circadian clock. Limiting evening screen light and alcohol improves sleep quality. Planning social commitments and activities for the dark months in advance counters the pull to hibernate, which is the behavioral core of CBT for SAD. None of these replace treatment for a full episode, but they make every treatment work better.
Prognosis
SAD is highly treatable and often preventable. Most people who start light therapy or medication before the season respond well, and those who complete CBT for SAD have lower recurrence in subsequent winters. The pattern can persist for many years without treatment, and roughly a third of people eventually develop non-seasonal depressive episodes as well, which is one more reason to treat it rather than wait for spring. With a plan in place each fall, the dark months become manageable rather than something to dread.
Frequently asked questions
Can you really get seasonal affective disorder in Florida or South Carolina?
Yes. Prevalence is lower than in northern states, but days still shorten by several hours in winter, and many people here spend their daylight hours indoors regardless of the weather. Patients who moved from the Northeast or Midwest often bring their pattern with them. We also see summer-pattern SAD, which may be more common in hot climates, with insomnia, appetite loss and agitation in July and August. The treatment for the winter pattern works the same here as anywhere.
Is a light box better than medication?
They work about equally well for winter-pattern SAD, so the choice depends on you. Light therapy acts fast, has few side effects and needs no prescription, but it requires 20 to 30 minutes every morning, which many people stop doing. Medication is easier to stay with and also treats non-seasonal depression and anxiety. Many patients use both for the first winter, then settle on whichever they prefer. CBT adds durable benefit either way.
When should I start treatment?
Before symptoms begin. If your depression usually starts in November, we begin light therapy, bupropion or CBT in late September or early October. Preventive treatment is more effective than treating an episode once it has taken hold. If you are already in an episode, do not wait for next year; treatment still works, usually within two to four weeks. Schedule an off-season evaluation so the plan is in place when fall comes.
Does insurance cover SAD treatment?
Psychiatric evaluation, medication management and therapy for seasonal depression are covered by most major insurance plans and Medicare, which Stedfast Psychiatry accepts. Light boxes are usually not covered, but a good 10,000 lux device costs roughly $40 to $150 and can often be paid for with an HSA or FSA. For patients without insurance, a self-pay new-patient visit is $185.
Can SAD be treated by telehealth?
Yes, and it is a good fit. Evaluation, medication management and CBT for seasonal depression all work by video for patients anywhere in Florida or South Carolina. We can review your light box setup on camera and adjust timing. In-person visits are available at any of our 13 offices if you prefer them or if labs are needed.
Do vitamin D supplements help?
The evidence is weak. Low vitamin D is common in winter and in people with depression, but controlled trials of vitamin D for SAD have been small and mostly negative. We check a level if you have risk factors and treat deficiency because it matters for bone and general health, but we do not rely on it to treat the depression. Light therapy, medication and CBT have far stronger support.
Could my seasonal pattern be bipolar disorder?
It is worth asking. Some people with a winter depression experience hypomania or mania in spring and summer, with unusually high energy, reduced need for sleep and impulsive decisions. That pattern points to bipolar disorder, and it changes treatment: antidepressants and light therapy are used cautiously and only with a mood stabilizer. We ask about spring highs at every SAD evaluation for exactly this reason.
Does SAD affect teenagers?
It can, and it is often mistaken for laziness or a school problem. Teens with SAD show the same winter pattern of oversleeping, carbohydrate cravings, withdrawal and falling grades, with recovery in spring. Light therapy and CBT are first-line for adolescents, with medication considered when symptoms are moderate to severe. Our child and adolescent psychiatry team evaluates teens with suspected seasonal depression.
Where to get treatment for seasonal affective disorder
Evaluation and treatment for seasonal affective disorder is available at every Stedfast Psychiatry office and by video across Florida and South Carolina.
Related conditions
If you are thinking about harming yourself, call or text 988 now, or go to the nearest emergency room. This page is educational and does not replace an evaluation. Clinical content reviewed by Dr. David Husted, board-certified psychiatrist.