What You Need to Know About Seasonal Affective Disorder

Seasonal affective disorder (SAD) is a condition that affects millions of individuals each year, with symptoms that can significantly impact quality of life and productivity.¹ In recognition of December being Seasonal Affective Disorder Awareness Month, it is important to explore approaches to managing SAD and strategies to reduce the burden of SAD on the health care system.

In recognition of December being Seasonal Affective Disorder Awareness Month, it is important to explore approaches to managing SAD and strategies to reduce the burden of SAD on the health care system. | Image credit: Ольга Рязанцева - stock.adobe.com

SAD is a type of depression that follows a recurring seasonal pattern, often triggered by changes in daylight and weather.² Unlike brief periods of feeling “down” or experiencing the “winter blues,” SAD significantly affects how an individual thinks, feels, and functions during specific times of the year. Most commonly, symptoms begin to occur in the late fall or early winter and typically resolve in spring or summer, a pattern often referred to as winter-pattern SAD or winter depression.

Common symptoms of SAD include persistent feelings of sadness, fatigue, and changes in sleep or appetite. Additionally, winter-pattern SAD is associated with oversleeping and carbohydrate cravings, while summer-pattern SAD includes symptoms of insomnia and weight loss.

Both Elon Musk and Vivek Ramaswamy, tapped by President-elect Donald J. Trump to help run a new effort dubbed the "Department of Government Efficiency," mentioned ending daylight savings time as a potential target, in an X post, according to The Washington Post.³ However, it was not immediately clear if they were serious.

How Does SAD Develop?

While the exact causes of SAD remain uncertain, research has provided insights into its potential biological and environmental factors.⁴ Reduced levels of serotonin are commonly observed in individuals with SAD. Sunlight exposure is also thought to influence molecules that help maintain serotonin levels, and shorter daylight hours in winter may disrupt this process, leading to mood changes. Furthermore, vitamin D deficiency, often exacerbated by limited sunlight exposure during the winter months, may reduce serotonin activity.

Melatonin, a critical hormone for sleep-wake cycles, also appears to play a role. In winter-pattern SAD, excessive melatonin production can lead to fatigue and oversleeping, while individuals with summer-pattern SAD may experience reduced melatonin levels, contributing to insomnia and restlessness. These disruptions in serotonin and melatonin levels can throw off the body’s internal clock or circadian rhythm, leading to impaired adaptability to seasonal changes.

Psychological factors may also contribute, as negative associations with seasonal changes—like winter’s cold and darkness or summer’s heat and long days—can exacerbate symptoms. While it’s unclear whether these thoughts are a cause or effect of SAD, they often become a focus in treatment strategies. Understanding these mechanisms is key to managing the disorder effectively.

Who is At Risk of Developing SAD?

SAD is not uncommon, with 2 in 5 Americans reporting that their mood worsens in winter, according to a recent poll from the American Psychiatric Association (APA).⁵ Although SAD affects a wide range of individuals, certain groups appear to be more vulnerable to its symptoms. Women are disproportionately impacted, with 45% reporting a decline in mood during winter compared with men (37%). Women are also more likely to experience behavioral changes, such as increased moodiness and fatigue, and feel the mental health effects of seasonal time changes.

Geographical differences also play a role in who is most impacted by SAD. Individuals living in Midwestern regions of the US report the highest rates of winter-related mood changes, with 52% feeling worse during the colder months. Those living in urban areas appear less affected, with only 36% reporting experiencing mood declines compared with 46% of individuals living in rural areas, who also reported greater mental health challenges related to the time change.

Evidence-Based Treatment Approaches

Primary treatment strategies for individuals with SAD fall into 4 categories: light therapy, psychotherapy, antidepressant medication, and vitamin D supplementation.⁴

Light therapy is the main treatment option for winter-pattern SAD, involving daily exposures to a bright light box to compensate for reduced natural sunlight. Psychotherapy, particularly cognitive behavioral therapy (CBT) adapted for SAD (CBT-SAD), aims to help patients reframe negative thoughts about seasonal changes and engage in mood-enhancing activities. Antidepressant medications, such as selective serotonin reuptake inhibitors (SSRIs) and bupropion, are often prescribed to address the underlying chemical imbalances associated with SAD. For those with winter-pattern SAD, vitamin D supplements may also be beneficial, though the effectiveness varies across studies.

As the days grow shorter and winter settles in, recognizing the signs of SAD and seeking timely support can make a meaningful difference. Whether through light therapy, engaging in enjoyable activities, or connecting with loved ones, proactive steps can help mitigate the challenges of the season. Raising awareness and providing resources can help foster a supportive environment for those affected by SAD and help everyone move toward brighter days ahead.

References

1. December is seasonal affective disorder (SAD) awareness month. National Alliance on Mental Illness. Accessed December 3, 2024. https://namiguilford.org/sad_month/.

2. Seasonal affective disorder (SAD). Mayo Clinic. Accessed December 3, 2024. https://www.mayoclinic.org/diseases-conditions/seasonal-affective-disorder/symptoms-causes/syc-20364651.

3. No more daylight savings time? Musk, Ramaswamy muse on ending clock changes. Washington Post. December 3, 2024. https://www.washingtonpost.com/health/2024/12/03/daylight-saving-time-musk-ramaswamy/.

4. Seasonal affective disorder. National Institute of Health. Accessed December 3, 2024. https://www.nimh.nih.gov/health/publications/seasonal-affective-disorder#:~:text=If%20you%20have%20noticed%20significant,pattern%20SAD%20or%20winter%20depression.

5. Two in five Americans say their mood worsens in winter; 29% say “falling back” hurts their mental health. American Psychiatric Association. News release. October 30, 2024. Accessed December 3, 2024. https://www.psychiatry.org/news-room/news-releases/apa-poll-mood-changes-in-winter#:~:text=Women%2C%20Midwesterners%20Feel%20the%20Impact,more%20about%20rural%20mental%20health.