Seasonal Affective Disorder: How to Recognize Symptoms and Find Treatment
Dr. Jamie Rogers • February 18, 2026
Quick Summary / TL;DR
Seasonal Depression GuideSeasonal Affective Disorder (SAD) is a recurring, seasonal pattern of depression —often tied to reduced daylight—affecting mood, energy, sleep, and daily functioning.
What it looks like
Low mood, fatigue, sleep/appetite changes, losing interest—often returning around the same time each year.
Why it happens
Reduced daylight can disrupt circadian rhythms and mood chemistry (serotonin/melatonin), affecting energy and sleep.
What helps
Often improves with lifestyle support + light therapy; therapy/medication can help; advanced options like TMS may help when symptoms persist.
When to reach out
If symptoms repeat seasonally and interfere with work, relationships, or routine—an evaluation can help clarify options.
Tip: Use this block as a “jump-in” summary for skimmers—then your detailed sections answer the “why” and “what to do.”
As the seasons change, it’s normal to feel shifts in energy, mood, or motivation. Shorter days and colder weather can leave many people feeling a little “off.” But for some, these changes go beyond occasional winter blues.
Seasonal affective disorder (SAD) is a form of clinical depression that follows a seasonal pattern and can significantly affect daily functioning, relationships, and overall well-being. Often emerging in the fall or winter months, SAD may cause persistent fatigue, mood changes, and disruptions in sleep or appetite linked to reduced daylight exposure.
At TrueNorth IMH in Greenville, NC, we help individuals understand seasonal depression and offer advanced, evidence-based treatment options to support long-term mental health.
What Is Seasonal Affective Disorder?
Seasonal affective disorder (SAD) is a type of depression linked to changes in seasons. Most people experience symptoms beginning in late fall or early winter, with improvement during the brighter months of spring and summer, though a smaller number of individuals experience symptoms during the warmer seasons instead.
Unlike temporary mood changes or holiday-related stress, SAD involves recurring patterns of depression that affect how a person feels, thinks, and functions over time.
SAD can influence mood, energy levels, sleep, and daily behavior, often returning at the same time each year. It is also diagnosed more frequently in women and may be more common in individuals living in regions with limited seasonal sunlight.
Because SAD follows a predictable pattern, recognizing the signs early can help individuals seek appropriate care and support.
Signs and Symptoms of Seasonal Affective Disorder
Seasonal affective disorder can look different from person to person, but as mentioned, the symptoms often follow a predictable pattern tied to seasonal changes. These shifts go beyond occasional mood changes.
They can affect your emotions, energy, sleep, and ability to function day to day. Recognizing the symptoms of seasonal affective disorder early can help you or someone you care about seek the right support. Below are some common signs and symptoms to watch out for.
- Persistent sadness or low mood
- Loss of interest in activities once enjoyed
- Fatigue or low energy
- Difficulty concentrating or making decisions
- Trouble sleeping (insomnia)
- Changes in appetite
- Feelings of hopelessness, guilt, or worthlessness
- Anxiety or restlessness
- Irritability or agitation
- Oversleeping or difficulty waking up
- Cravings for carbohydrates or sugary foods
- Weight gain
- Social withdrawal or desire to “hibernate”
If these symptoms appear at the same time each year and begin to interfere with daily life, it may be a sign of SAD rather than temporary seasonal stress or passing “winter blues.”
Seasonal Affective Disorder: Common Symptoms
If multiple symptoms show up seasonally and disrupt daily life, it may be worth discussing support options.
The Science Behind Seasonal Depression
Seasonal affective disorder is not simply a reaction to cold weather or darker days. It involves real biological changes in the brain and body that influence mood, energy, and behavior.
Researchers believe seasonal depression develops through a complex interaction between light exposure, brain chemistry, and the body’s internal rhythms. Understanding these underlying mechanisms can help explain why symptoms occur and why certain treatments are effective.
Circadian Rhythms and Light Exposure
Your body runs on an internal clock called the circadian rhythm, which regulates sleep, energy levels, and mood. This “clock” relies heavily on sunlight to stay balanced.
When daylight hours decrease in the fall and winter, the body receives fewer signals to stay alert and energized. This disruption can throw off sleep–wake cycles, leading to fatigue, sluggishness, and mood changes commonly associated with seasonal depression.
Reduced sunlight exposure can also affect brain pathways that regulate emotional and behavioral responses, further contributing to depressive symptoms.
Serotonin and Mood Regulation
Serotonin is a neurotransmitter that plays an essential role in regulating mood and emotional stability. Exposure to sunlight helps maintain healthy serotonin activity in the brain.
During darker months, reduced sunlight may lower serotonin levels, which can trigger feelings of sadness, low motivation, and depression symptoms. These changes in mood-regulating brain chemicals are believed to be a key factor in seasonal affective disorder.
Melatonin and Sleep Cycles
Melatonin is a hormone that helps control sleep patterns and responds directly to darkness. When days become shorter, the body produces more melatonin, which can increase sleepiness and reduce energy levels. This shift may contribute to the excessive fatigue and changes in sleep commonly experienced in seasonal depression.
Vitamin D Deficiency
Sunlight also helps the body produce vitamin D, which supports brain health and serotonin activity. Reduced sun exposure during winter months may lead to lower vitamin D levels, potentially worsening mood changes and contributing to depressive symptoms.
Brain Response to Seasonal Changes
Research
also suggests that specialized light-sensitive pathways in the brain help regulate emotional responses to environmental changes. When seasonal light patterns shift, these biological systems may respond differently in some individuals, creating an interaction between environmental triggers and brain function that contributes to SAD.
Who Is Most at Risk for SAD?
Seasonal affective disorder can affect anyone, but some people may be more vulnerable than others.
- Women receive SAD diagnoses more often, and it typically begins in young adulthood.
- Individuals with a family history of depression may be at higher risk.
- Living in regions with limited seasonal sunlight, where shorter days can intensify symptoms, can also increase risk.
- People with existing mood disorders, including major depression or bipolar disorder, may also experience seasonal patterns that affect their mental health more strongly.
Treatment Options for Seasonal Affective Disorder
Seasonal affective disorder is highly treatable, and many people find relief through a combination of therapies tailored to their needs. Treatment often focuses on restoring balance to the body’s internal rhythms, improving mood regulation, and supporting overall mental health.
Lifestyle and Behavioral Strategies
Simple daily habits can play an important role in managing seasonal depression. Regular exercise, time outdoors, and consistent exposure to natural sunlight can help improve mood and energy levels. Maintaining strong social connections and practicing healthy sleep habits also support emotional well-being and help regulate the body’s internal rhythms.
Light Therapy
Light therapy is one of the most widely used treatments for seasonal depression. It typically involves sitting near a specialized light box that emits 10,000 lux of bright light for about 30 minutes each morning. This exposure helps regulate circadian rhythms, improve mood, and reduce symptoms by mimicking natural sunlight. Research supports light therapy as a safe, noninvasive, and evidence-based treatment option for depression.
Psychotherapy and Medication
Psychotherapy, particularly cognitive behavioral therapy (CBT), can help individuals identify negative thought patterns and develop healthier coping strategies. Antidepressant medications may also be prescribed to help regulate mood-related brain chemicals. These treatments are commonly used to manage seasonal depression and may be combined with other approaches for more effective symptom relief.
TMS Therapy for Seasonal Depression
For individuals who do not find sufficient relief from traditional treatments, Transcranial Magnetic Stimulation (TMS) offers an advanced, noninvasive option. TMS therapy uses targeted magnetic pulses to stimulate areas of the brain involved in mood regulation, helping restore healthy neural activity.
Research shows that depression with a seasonal pattern responds to repetitive TMS similarly to other forms of major depression, making it a promising treatment option. By improving mood-regulating brain function, TMS may reduce symptoms when medication, therapy, or light treatment alone is not enough.
Treatment Options: A Simple Care Path
Readers love seeing “what to try first” and “what’s next” at a glance.
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Start with daily supports
Consistent sleep, movement, time outdoors, morning light, and staying socially connected.
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Consider light therapy
Many people try structured morning bright-light exposure to support circadian rhythm and energy.
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Add therapy and/or medication as needed
CBT and antidepressants can help regulate mood patterns and coping skills.
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Explore advanced options
If symptoms persist despite first-line approaches, noninvasive neuromodulation like TMS may be a next step.
When to Seek Help for Seasonal Depression
It’s normal to have occasional low days, but if your mood changes persist or begin to interfere with your daily life, it may be time to seek professional support. Ongoing fatigue, persistent sadness, or loss of motivation that affects work, relationships, or routine activities should not be ignored.
Early evaluation and treatment can help prevent symptoms from worsening and support your long-term recovery. A mental health professional can provide an accurate diagnosis and guide you toward the most effective care.
How TrueNorth IMH Helps Patients Experiencing SAD in Greenville, NC
Seasonal affective disorder is a real and treatable condition, not something you simply have to push through each year. Understanding the symptoms and causes can help you take meaningful steps toward better mental health. If you’re experiencing seasonal changes in mood or energy, reaching out for professional support can be the first step toward feeling like yourself again.
At TrueNorth IMH, we provide specialized mental health care designed to support individuals experiencing seasonal depression and other mood disorders. Our team offers advanced TMS therapy and personalized treatment plans tailored to your unique symptoms, history, and goals. We take a compassionate, patient-centered approach, focusing on lasting relief and improved quality of life.
Conveniently located in Greenville, NC, TrueNorth IMH is committed to helping members of our local community access effective, evidence-based care.
If you’re ready to take the next step, you can learn more about our TMS therapy services or schedule a consultation to explore your treatment options.
Seasonal Affective Disorder FAQs
Quick answers to common questions readers ask before they reach out for help.
Is SAD the same as “winter blues”?
When do SAD symptoms usually start?
What are the most common symptoms?
What treatments are typically tried first?
Can TMS help with seasonal depression?
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