As the days grow shorter and the weather turns colder, many people notice a shift in their mood and energy. It’s common to feel more tired, irritable, or low during the winter months, and sometimes these changes can be confusing or even embarrassing. What you might be experiencing is not just “winter blues”—Seasonal Affective Disorder (SAD) is a real, diagnosable condition, and the good news is that it is treatable. Understanding the signs and knowing that support is available can make a big difference in getting through the darker months.
What Is Seasonal Affective Disorder?
Seasonal Affective Disorder (SAD) is a recurring mood condition where symptoms show up during the fall and winter months and naturally improve as spring and summer roll in (Chen et al, 2024). It’s officially recognized in the DSM-5 as a subtype of major depressive disorder with a seasonal pattern (Chen et al, 2024).
To receive a diagnosis of SAD, a person typically needs to show:
- A clear seasonal pattern to their mood episodes—like depression, hypomania, or mania—for at least a few years in a row (Chen et al, 2024).
- Full relief from symptoms once the season changes, often shifting from deep depression to a stable or improved mood (Chen et al, 2024).
- More seasonal episodes than non-seasonal ones (Chen et al, 2024).
SAD affects about 1.5% to 10% of people, with higher rates seen in areas farther from the equator, though it can occur anywhere (Chen et al, 2024). The condition tends to appear at the same time each year—most often in the fall or winter—and symptoms usually lift completely by spring or summer (Galima et al, 2020). While the “winter blues” are mild and temporary, SAD involves stronger, more disruptive depressive symptoms that follow a clear seasonal pattern and meet clinical criteria.
Common Symptoms of SAD
People with Seasonal Affective Disorder (SAD) often experience a range of symptoms, which may include:
- Persistent low mood
- Ongoing feelings of sadness
- Low energy, fatigue, or a general sense of being drained
- Sleeping more than usual
- Craving carbohydrates
- Weight gain
- Difficulty concentrating
- Loss of interest in usual activities
- Social withdrawal
- Irritability
- Being easily tearful
- (Melrose, 2015)
In some cases, these symptoms may become severe enough to interfere with daily functioning.
What Causes SAD?
Seasonal Affective Disorder stems from reduced exposure to sunlight during the fall and winter months, which can disrupt the body’s internal 24-hour clock, or circadian rhythm (Melrose, 2015). When daylight decreases, the balance between serotonin and melatonin shifts—serotonin levels may drop, while melatonin levels can rise—making it harder to regulate mood, energy, and sleep (Melrose, 2015). People with SAD often produce too much melatonin, a hormone released in darkness that increases sleepiness, and may also struggle to maintain stable serotonin levels, which play a key role in mood regulation (Melrose, 2015).
Limited sunlight in winter can also lead to lower vitamin D production. Because vitamin D supports serotonin activity, low levels of this nutrient have been linked to more significant depressive symptoms (Melrose, 2015). In addition to these biological factors, genetics, geographic location, reduced time spent outdoors, and lifestyle factors such as shift work may further increase the risk of developing SAD.
Who Is Most at Risk?
People are more likely to develop SAD if they live in northern climates or higher latitudes, have a history of depression or bipolar disorder, or have a family history of mood disorders, including SAD (Galima et al, 2020). Women tend to be affected at higher rates than men, and the condition is also more common in young adults, particularly those between 18 and 30 years old (Galima et al, 2020).
How We Diagnose SAD in Our Practice
At ONE, our providers diagnose Seasonal Affective Disorder (SAD) through a comprehensive clinical evaluation that includes reviewing the patient’s psychiatric history, examining the pattern and timing of symptoms, using screening tools such as the PHQ-9 and seasonal pattern assessments, and ruling out medical causes like thyroid dysfunction, anemia, or sleep disorders. Our team also emphasize the importance of tracking symptom patterns across multiple years to confirm seasonal recurrence.
Evidence-Based Treatment Options for SAD
Light Therapy
Light therapy is one of the most well-supported treatments for seasonal affective disorder (SAD). It typically involves the use of commercially available “light boxes” that emit bright light while filtering out harmful ultraviolet rays (Galima et al., 2020). Sessions usually last 30 to 60 minutes per day, with light intensities ranging from 2,500 to 10,000 lux; 10,000 lux appears to be the most effective and should ideally be used at the same time each day (Galima et al., 2020).
Light therapy is generally considered low risk. For comparison, the midday sun provides approximately 50,000 to 100,000 lux. However, individuals with preexisting eye conditions or those taking medications that increase photosensitivity may benefit from obtaining clearance from an eye care professional before beginning treatment (Galima et al., 2020).
Research indicates that light therapy can produce mild to moderate improvements in depressive symptoms, with some studies suggesting it may be more effective than placebo or other interventions (Chen et al., 2024). During treatment, clients should sit with the light box positioned slightly above eye level and angled downward at approximately 30 degrees. They may engage in activities such as reading, eating, using a computer, or meditating during the session, but should avoid looking directly into the light. Glasses may be worn as long as they do not have transition, blue-light–blocking, or tinted lenses.
Psychotherapy
Cognitive Behavioral Therapy designed specifically for Seasonal Affective Disorder (CBT-SAD) is also a helpful treatment option. It focuses on the thoughts and behaviors that tend to fuel winter-related depression, using strategies like behavioral activation and cognitive restructuring (Fields, 2024). Behavioral activation helps counter wintertime anhedonia by encouraging you to identify, plan, and follow through with enjoyable activities (Fields, 2024). By increasing engagement in things that feel rewarding, it can boost mood and reduce seasonal depressive symptoms (Fields, 2024). Cognitive restructuring, on the other hand, works on challenging and reframing negative thoughts or core beliefs tied to the winter months—such as reactions to shorter days, limited sunlight, or gloomy weather (Fields, 2024).
Medication
Pharmacological treatments, particularly selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), have strong evidence for managing SAD (Chen et al, 2024). For example, fluoxetine (Prozac) has been shown to be as effective and safe as light therapy (Galima et al, 2020). Medications may be recommended for individuals with moderate to severe symptoms, and starting treatment early in the season can help reduce the risk of relapse. Some research also suggests that vitamin D supplementation may provide additional support (Melrose, 2015).
Lifestyle Supports
Lifestyle strategies can complement clinical treatments. Increasing outdoor exposure to natural light, maintaining regular sleep schedules, exercising regularly, and paying attention to nutrition—including vitamin D intake—can all help manage SAD symptoms (Galima et al, 2020). Structuring daily routines to stay engaged and active can further support mood and overall well-being. While clinical trials are limited, these approaches are low-risk and offer additional health benefits beyond mood support (Galima et al, 2020).
How Our Psychiatry Practice Supports Patients With SAD
Our psychiatry practice supports patients with Seasonal Affective Disorder (SAD) by creating personalized treatment plans, providing collaborative care that may include therapy, medication, and lifestyle guidance, and closely monitoring progress across seasons. We also offer telehealth options during the winter months and encourage patients to reach out early, before symptoms peak.
Concerned about your mental health? Contact us today to schedule with a licensed psychiatric nurse practitioner in Columbus, Ohio.
Chen, Z., Zhang, X., & Tu, Z. (2024). Treatment measures for seasonal affective disorder: A network meta-analysis. Journal of Affective Disorders, 350, pp. 531-536. https://doi.org/10.1016/j.jad.2024.01.028
Fields, T. (2024). Seasonal Affective Disorder: A Narrative Review. Journal of Clinical Psychology and Neurology, 2(1): 1-8. DOI: doi.org/10.61440/JCPN.2024.v2.14
Galima, S., Vogel. S., & Kowalski, A. (2020). Seasonal Affective Disorder: Common Questions and Answers. Am Fam Physician. 102(11), 668-672.
Melrose, S. (2015). Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches. Depression Research and Treatment. https://doi.org/10.1155/2015/178564
