Seasonal Affective Disorder: How Seasonal Changes Can Affect Mental Health
Seasonal Affective Disorder, often called SAD, is a form of depression that follows a predictable seasonal pattern. It most commonly appears in the fall and winter months, when daylight hours decrease, and improves in the spring or summer. For some people, symptoms can also emerge during warmer months, though this pattern is less common.
While many people notice changes in mood or energy during certain seasons, SAD goes beyond temporary discomfort. It is a recognized mental health condition that can significantly affect daily functioning, emotional wellbeing, and quality of life (American Psychiatric Association, 2022).
What Is Seasonal Affective Disorder?
Seasonal Affective Disorder is diagnosed when depressive symptoms occur during the same season for at least two consecutive years, with improvement as the season changes. SAD shares many features with major depressive disorder, with seasonality being the defining factor.
Symptoms are not simply a reaction to colder weather or holiday stress. Research shows that seasonal changes can affect brain chemistry, circadian rhythms, and hormone regulation, all of which play important roles in mood stability (Rosenthal et al., 1984).
Common Symptoms
Symptoms of SAD can vary in intensity, but often include:
Persistent low mood or sadness
Loss of interest in activities that once felt enjoyable
Low energy or fatigue
Difficulty concentrating or thinking clearly
Sleeping more than usual or feeling unrested
Increased appetite, especially cravings for carbohydrates
Weight changes
Social withdrawal or isolation
Feelings of hopelessness or emotional heaviness
In summer-pattern SAD, symptoms may include insomnia, irritability, anxiety, restlessness, or reduced appetite.
Why Seasonal Changes Matter
Seasonal shifts can affect mental health through several biological pathways. Reduced exposure to sunlight can disrupt the body’s internal clock, which helps regulate sleep, mood, and energy. Seasonal changes may also influence serotonin and melatonin levels, which affect mood regulation and sleep-wake cycles. Lower vitamin D levels during darker months may also contribute to depressive symptoms (National Institute of Mental Health, 2023).
For individuals who are more biologically sensitive to these changes, seasonal shifts can trigger depressive symptoms that feel difficult to manage without support.
Who Is More Likely to Experience SAD?
Seasonal Affective Disorder can affect people of all ages. Risk factors include:
Living in regions with limited winter daylight
A personal or family history of depression or bipolar disorder
Being female
Younger age, with symptoms often beginning in early adulthood
SAD can also occur alongside other mental health conditions, which may increase symptom severity or persistence.
Treatment Options
Seasonal Affective Disorder is treatable, and many people experience meaningful improvement with appropriate care. Treatment plans are individualized and may include:
Light Therapy
Daily use of a clinically approved light box can help regulate sleep and mood by simulating natural sunlight.
Therapy
Cognitive Behavioral Therapy can help identify seasonal thought patterns, develop coping strategies, and reduce the likelihood of symptoms returning each year.
Medication
Antidepressant medications may be recommended when symptoms are moderate to severe or significantly interfere with daily life.
Lifestyle Support
Consistent routines, regular physical activity, healthy sleep habits, and increased exposure to natural light can support overall mental health.
When to Seek Support
If seasonal mood changes begin to interfere with daily functioning, relationships, or emotional well-being, professional support can be an important step. Seasonal Affective Disorder and related seasonal mood challenges are medical conditions that respond well to evidence-based treatment. Early support often leads to better outcomes and helps prevent symptoms from becoming more disruptive over time. With appropriate treatment, individuals can restore balance, energy, and emotional clarity throughout the year.
References (APA Style)
American Psychiatric Association. (2022). DSM-5-TR: Diagnostic and statistical manual of mental disorders (5th ed., text rev.). https://doi.org/10.1176/appi.books.9780890425787
National Institute of Mental Health. (2023). Seasonal affective disorder. https://www.nimh.nih.gov/health/topics/seasonal-affective-disorder
Rosenthal, N. E., Sack, D. A., Gillin, J. C., Lewy, A. J., Goodwin, F. K., Davenport, Y., Mueller, P. S., Newsome, D. A., & Wehr, T. A. (1984). Seasonal affective disorder: A description of the syndrome and preliminary findings with light therapy. Archives of General Psychiatry, 41(1), 72–80. https://doi.org/10.1001/archpsyc.1984.01790120076010
