Understanding Seasonal Affective Disorder, With Molly Sherb, Ph.D.

Credit: The Mount Sinai Health Center

As the days grow shorter and sunlight fades earlier each afternoon, many people notice a shift in their mood, energy and motivation. While some may brush these feelings off as the “holiday blues,” for others, the change is deeper and more persistent. Seasonal affective disorder (SAD) is a type of depression linked to disruptions in the body’s internal clock, triggered by reduced daylight during late fall and winter. In an interview with The Educated Patient, Molly Sherb, Ph.D., a licensed clinical psychologist with the Behavioral Health Team at the Mount Sinai Health Center, explains how SAD differs from everyday seasonal stress, who is most at risk, the most common symptoms to watch for, and the effective, evidence-based treatments that can help people feel more like themselves again.

For readers who may be unfamiliar, what exactly is SAD, and how is it different from the general “holiday blues” many people experience?

Molly Sherb, Ph.D.: SAD and “holiday blues” share similar symptoms while also having distinguishable differences. Holiday blues consist of low mood, sadness, fatigue, etc., specifically connected to the holiday season. SAD is a broader psychological disorder linked to fewer daylight hours, which disrupts the circadian rhythm throughout late fall and winter, extending beyond holiday time.

What are the most common symptoms people should watch for if they think their low mood is more than just seasonal stress?

MS: The most common symptoms of SAD include but are not limited to persistent low mood, sadness, fatigue, anhedonia, low motivation, sleeping and eating disturbances, irritability and social isolation.

Who is most at risk for SAD, and why does it tend to appear as the days get shorter?

MS: There are several groups of people who are at higher risk for developing SAD.

• Individuals who live in areas of the country (such as the northern U.S.) where daylight hours are shorter and it becomes darker earlier.
• Individuals with a family history of depressive or other mood disorders
• Women are at higher risk in general due to differences in hormonal and biological factors.
• Individuals between the ages of 18 and 30, as this is typically when symptoms of SAD begin.

What evidence-based treatments are available for SAD, and how effective are they?

MS: There are several effective evidence-based treatments for SAD.

1. Light therapy is a primary treatment modality for reducing symptoms of SAD by replacing the natural light your body is lacking with artificial light transmitted through a light box. There are many different types of light boxes, and it is best to discuss the various options with your physician to determine the right fit. This treatment involves sitting in front of the light box for about 30 minutes each morning to “wake your body up” and send the message to your brain that daytime has begun. This helps to reset the internal clock and regulate circadian rhythm. Light also increases serotonin levels, which leads to improved mood. Light therapy is effective as both a stand-alone treatment as well as in combination with talk therapy.
2. Cognitive behavioral therapy has also demonstrated efficacy in treating SAD by challenging automatic negative thoughts related to the seasonal changes. This therapy helps individuals recognize and understand how their automatic negative thoughts contribute to the exacerbation of depressive symptoms. It works to empower clients to reframe their thinking and in turn improve their mood. The skill-building techniques learned in therapy have long-lasting effects, as they can be carried into future years.
3. Antidepressant medications, including selective serotonin reuptake inhibitors (SSRIs), help to increase overall serotonin levels in the brain and help reset the chemical changes caused by lack of daylight. Other types of antidepressant medications can help to increase dopamine levels, resulting in improved mood. It’s important to work directly with a physician trained in treating psychiatric disorders to determine which medication is right for you.

What role do lifestyle habits — like sleep, movement and nutrition — play in managing seasonal symptoms?

MS: Lifestyle habits play a critical role in reducing symptoms of SAD, as behavior directly impacts mood and overall physical and mental well-being. Because SAD is directly linked to reduced sunlight, it’s important to spend as much time in brightness as possible. Sit by a window or, better, take a break and move around, get outside for fresh air. This increases exposure to direct sunlight and increases vitamin D levels, while movement increases endorphins and tells your brain it’s time to be awake.

Nutrition also plays a key role in managing symptoms of SAD. Eating balanced and nutrient-dense meals throughout the day provides your body with the fuel it needs to combat fatigue and low energy. Eating frequently throughout the day can also help to combat blood sugar spikes.

Further, establishing solid and consistent wind-down and wake-up routines can help prime the body for when it’s time to go to sleep and when it’s time to be awake. A 20- to 30-minute routine at the start and end of the day helps to smooth these transitions and stabilize the circadian rhythm.

What message do you want people to hear about seeking help for seasonal depression or emotional challenges during the holiday season?

MS: Life is hard, it is challenging, and it can bring you to your knees. What knocks us down is not in our control, but the ability to get back up can be. Sometimes we need help doing that, and asking for help should be viewed a sign of strength. Be kind to yourself this holiday season and during low moments, and try to approach yourself with curiosity instead of criticism. Ask yourself “what do I need?” instead of “what’s wrong with me?” This question prompts self-reflection and can help you identify people, places and spaces that can support and guide actionable next steps to begin shifting out of a low emotional space.