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Seasonal Affective Disorder (SAD): Symptoms, Causes and Treatments

Beth Pausic, Psy.D.

Reviewed by Beth Pausic, Psy.D

Written by Rachel Sacks

Published 09/22/2022

Updated 08/08/2023

Seasonal changes from summer to fall can mean many things: changing leaves, holidays just around the corner and mood changes. While there are so many fun things about fall and winter, there are also some not-so-fun aspects — like when searches for seasonal depression symptoms and weighted blankets spike.

Many people seem to recognize that they’re experiencing seasonal depression when their typical symptoms of depression come at the same time as a blizzard. It makes sense — there’s less sunlight, fewer social activities and you go outside less, possibly making you feel lonely and isolated.

But did you know that seasonal depression — or seasonal affective disorder — can also happen in the summer? While many people get happier as the weather gets warmer and they spend more time outside, others find themselves getting symptoms of depression as they put away sweaters and bring out shorts. 

Keep reading this guide to learn more about seasonal affective disorder, as well as its causes, seasonal depression symptoms and more.

What Causes Seasonal Affective Disorder?

Before we go into what causes seasonal depression, we’ll answer what’s likely your first question: what is seasonal affective disorder?

Seasonal affective disorder, typically abbreviated as SAD (a very on-the-nose abbreviation, of course), is a mood disorder that happens in the same season every year.

While many people may experience the winter blues when the temperature drops, SAD is a more severe type of depression that can affect people in the winter — known as winter-pattern SAD or winter depression — as well as cause summer depression.

This mood disorder commonly affects women (a really not-so-fun fact) and is more common in people with major depressive disorder or bipolar disorder. Additionally, people with SAD tend to have other mental disorders, such as anxiety disorder, eating disorders or panic disorder.

So now that we’ve covered what seasonal affective disorder is, we can move on to what’s likely your next question — why seasonal depression happens. Surely we’re not just getting disproportionately upset over cold weather and earlier sunsets, right?

There are several theories that point to a lack of sunlight and hormone changes as the causes of SAD. 

The significant decrease in sunlight affects your body’s production of two key hormones, serotonin and melatonin, which regulate your circadian rhythm — aka your internal clock of when to be awake and when to sleep.

Lower serotonin levels also affect your mood, resulting in feelings of sadness or hopelessness. So, those super early sunsets could very well be the reason you feel down.

But a low mood is just one of several symptoms of seasonal affective disorder, which we dive into below.

Symptoms of Seasonal Affective Disorder

Seasonal depression symptoms can start in late spring and early summer, but are most common in late fall and early winter. Either way, they’ll stick around throughout the season in which they start, and can range in severity from mild to moderate.

While SAD symptoms can vary depending on which season this form of depression happens in (more on that in a bit), there are some common signs across seasons:

  • Feeling depressed or in a low mood nearly every day

  • Sleep issues

  • Anxiety

  • Loss of interest in typically enjoyable activities

  • Irritability

  • Low energy levels

  • Hopelessness

  • Difficulty concentrating

  • Suicidal thoughts

  • Carb cravings

Fall and Winter SAD Symptoms

If you’re experiencing symptoms of seasonal affective disorder in the fall and winter, you may be noticing:

  • Oversleeping (hypersomnia)

  • Craving carbohydrates

  • Overeating

  • Weight gain

  • Feeling like “hibernating” or withdrawing socially

Spring and Summer SAD Symptoms

Meanwhile, SAD symptoms in the spring and summer may look slightly different than those in the fall and winter:

  • Trouble sleeping (insomnia)

  • Poor appetite

  • Weight loss

  • Restlessness and agitation

  • Episodes of violent behavior

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How Seasonal Affective Disorder is Diagnosed

If you’re feeling down and hopeless and the weather outside is reminiscent of a winter wonderland, would you be able to say you have seasonal affective disorder? Not quite.

According to the National Institute of Mental Health (NIMH), someone must have symptoms of major depression or other SAD symptoms and have a seasonal pattern of depressive episodes in order to be diagnosed with seasonal depression.

Additionally, the DSM-5 (a reference manual for mental health conditions) states that seasonal depression has a beginning and ending during a specific season every year and that the individual must have experienced more seasons with depression than seasons without depression throughout their life.

Treating Seasonal Depression (SAD)

Although dealing with seasonal depression is difficult, this type of mood disorder is also highly treatable:

  • Antidepressant medications. Often a first-line treatment for depression, antidepressants may be used for SAD. Antidepressants that have been shown to be effective for seasonal depression include selective serotonin reuptake inhibitors (SSRIs) like fluoxetine (Prozac®), escitalopram (Lexapro®) and sertraline (Zoloft®), as well as bupropion (Wellbutrin XL®), an atypical antidepressant. However, bupropion may cause more side effects.

  • Light therapy. Light therapy uses sunlight lamps or a light box to mimic natural sunlight and help increase melatonin and serotonin levels. It’s a promising treatment option for those with seasonal depression symptoms or a delayed circadian phase.

  • Vitamin D. Low levels of vitamin D have been associated with depression and serotonin production also depends on the availability of this particular vitamin. Making sure you eat nutrient-rich foods or adding a supplement to increase your vitamin D levels could help reduce symptoms of seasonal affective disorder.

  • Psychotherapy. Also known as talk therapy, psychotherapy like cognitive behavioral therapy (CBT) can help you focus on thinking positively through the darker months. You can start therapy in-person or get connected with a mental health professional through online therapy.

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Coping with Seasonal Affective Disorder

Certain types of depression can affect people at specific times — and seasonal affective disorder is just one example of this. Here’s what you need to know.

  • Seasonal affective disorder is a type of depression that occurs during specific seasons, whether in the fall and winter months or spring and summer.

  • Symptoms of SAD can look a lot like symptoms of major depressive disorder, including feelings of hopelessness, trouble sleeping, weight changes, anxiety, a loss of interest in usual activities and difficulty focusing.

  • A healthcare provider or mental health professional may diagnose you with seasonal depression if your depressive episodes occur during the same months each year, for multiple years in a row.

  • Seasonal depression can be treated with antidepressants, psychotherapy, light therapy, vitamin D supplementation or a combination of treatments, if that’s right for you.

Regardless of what season you experience SAD in, seasonal depression can definitely take a toll on your mental health. If you think you might be dealing with seasonal affective disorder, getting connected with a healthcare provider through online psychiatry or using online mental health services can provide you with some answers and treatment options.

5 Sources

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references.

  1. Munir, S., & Abbas, M. (2023). Seasonal Depressive Disorder. StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK568745/
  2. NIMH » Seasonal Affective Disorder. (n.d.). NIMH. Retrieved from https://www.nimh.nih.gov/health/publications/seasonal-affective-disorder
  3. Melrose S. (2015). Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches. Depression research and treatment, 2015, 178564. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4673349/#B1
  4. Gartlehner, G., Nussbaumer-Streit, B., Gaynes, B. N., Forneris, C. A., Morgan, L. C., Greenblatt, A., Wipplinger, J., Lux, L. J., Van Noord, M. G., & Winkler, D. (2019). Second-generation antidepressants for preventing seasonal affective disorder in adults. The Cochrane database of systematic reviews, 3(3), CD011268. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6422318/
  5. Campbell, P. D., Miller, A. M., & Woesner, M. E. (2017). Bright Light Therapy: Seasonal Affective Disorder and Beyond. The Einstein journal of biology and medicine : EJBM, 32, E13–E25. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6746555/

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Beth Pausic, Psy.D

Dr. Beth Pausic is a clinical psychologist and oversees the therapy platform at Hims & Hers. 

Prior to Hims & Hers, Beth worked in senior roles at several behavioral healthcare startups focused on the digital delivery of emotional support and treatment through both conventional and innovative approaches. 

Her experience prior to working in telebehavioral health includes over 15 years as a Clinical Administrator and provider in diverse clinical settings. In her clinical work, she primarily focused on anxiety, depression and relationships. 

Dr. Pausic received her doctorate from George Washington University. You can find Beth on Linkedin for more information.


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