Understanding Seasonal Affective Disorder (S.A.D.); Why Winter Can Feel Heavier and How to Find Your Way Through It
Seasonal shifts can affect us in surprising and deeply personal ways. For some, winter is not only a change in weather, but also a change in mood, energy, and emotional balance. Shorter days, colder temperatures, and reduced sunlight can create a heaviness that settles quietly but persistently.
Many people find themselves feeling more tired, less motivated, and emotionally drained during this time of year, often without realizing there is a name for what they are experiencing. This pattern is known as Seasonal Affective Disorder (S.A.D.), a form of depression influenced by changes in light and seasonal rhythms [1]. Understanding why it happens helps us allow ourselves and others greater compassion. You can explore more supportive mental health and wellness resources in our Wellness Corner.
What Is S.A.D.?
Seasonal Affective Disorder (S.A.D.) is a subtype of depression that follows a predictable seasonal cycle. Most commonly, symptoms begin in late fall or early winter and gradually lift as spring brings longer days and more sunlight. It is more than “winter blues”; it is a legitimate mood disorder with emotional, physical, and cognitive symptoms that may interfere with daily life.
S.A.D. is recognized by mental health organizations worldwide and is understood as a biological and psychological response to reduced sunlight exposure [2]. It is treatable, common, and nothing to be ashamed of.
What are the Contributing Factors?
S.A.D. develops through a combination of biological, environmental, and emotional factors. While every person’s experience is unique, research has identified several key contributors.
Reduced sunlight exposure
During fall and winter, shorter daylight hours can disrupt the body’s internal clock, or circadian rhythm, which helps regulate sleep, energy, and mood. When this rhythm is out of sync, it can become harder to feel emotionally steady or alert during the day [3].
Serotonin changes
Sunlight plays a role in the body’s production of serotonin, a neurotransmitter that supports mood and emotional well-being. Reduced light exposure may contribute to lower serotonin activity, which can be associated with depressive symptoms [4].
Melatonin imbalance
Darker days can increase melatonin production, the hormone that helps regulate sleep. Higher melatonin levels can lead to increased fatigue, drowsiness, and difficulty waking up or feeling fully alert. For those sensitive to seasonal changes, this shift can significantly affect daily functioning [5].
Vitamin D and mood
Sunlight also supports the body’s production of vitamin D. Low vitamin D levels have been linked with mood changes and depressive symptoms, especially during winter months when sun exposure tends to be limited [6].
Emotional and social stressors
Seasonal emotional health is shaped not only by biology, but also by life circumstances. Holiday expectations, financial strain, changes in routine, and social isolation can intensify emotional vulnerability.
What are the signs?
S.A.D. often feels like a gradual emotional fog, subtle at first, then increasingly difficult to ignore. People may notice a shift in the way they think, feel, and move through their day-to-day lives.
Common emotional signs may include:
- Feeling sad, low, or emotionally heavy for much of the day
- Increased irritability or sensitivity
- Loss of interest in activities that usually feel meaningful
- Feeling disconnected from others or wanting to withdraw
Physical and energy-related signs may include:
- Low energy or persistent fatigue
- Sleeping more than usual or struggling to get out of bed
- Increased appetite, often with cravings for carbohydrates or sweets
- Unexplained weight changes
- Difficulty concentrating or feeling mentally “foggy”
Behavioural signs may include:
- Canceling plans or withdrawing from social connections
- Procrastinating or feeling unable to complete everyday tasks
- Feeling “slowed down” physically and emotionally
Unlike chronic depression, which can be present throughout the year, S.A.D. symptoms tend to appear and fade with the seasons. However, the impact during those months is very real and deserving of care and support.
Seasonal struggles are not always visible. Someone who seems quiet, distant, or frequently tired may be carrying emotional weight shaped by the time of year.
If You Are Struggling
If winter feels especially heavy for you, please know that what you are experiencing is valid. You are not weak for finding this season difficult, and you do not have to navigate it alone.
References
- Mayo Clinic. “Seasonal Affective Disorder (SAD).”
https://www.mayoclinic.org/diseases-conditions/seasonal-affective-disorder/
- National Institute of Mental Health (NIMH). “Seasonal Affective Disorder.”
https://www.nimh.nih.gov/health/topics/seasonal-affective-disorder
- Cleveland Clinic. “Seasonal Affective Disorder (SAD): Causes & Symptoms.”
https://my.clevelandclinic.org
- Lambert, G.W. et al. “Effect of sunlight and serotonin turnover.” The Lancet.
- Wirz-Justice, A. “Seasonality in depression: melatonin and circadian rhythms.” Dialogues in Clinical Neuroscience.
- Holick, M.F. “Vitamin D deficiency and mood disorders.” New England Journal of Medicine.
