Seasonal Affective Disorder: Definition, Causes, & Treatments

In fact, nearly 10 million Americans struggle with the symptoms of Seasonal Affective Disorder every year (Kurlansik & Ibay, 2012). While the majority of cases of SAD occur during the colder months of the year, summer is not a time for fun in the sun for everyone. It is not unheard of for some people to experience Seasonal Affective Disorder​ during the spring and summer—a type of depression known as Summer-Seasonal Affective Disorder. Contrary to Winter-Seasonal Affective Disorder, the symptoms of Summer-SAD will typically resolve during early autumn.

Seasonal Affective Disorder Causes ​
Research on Seasonal Affective Disorder remains relatively new, first dating back to Dr. Norman Rosenthal’s work in the 1980s. Thus, the causes of Seasonal Affective Disorder are not entirely clear. However, psychologists theorize that three specific biological and neurological changes, or a combination of all of them, can cause a shift in our psychological and social wellness. I will outline these three possible causes below. 

• A change in serotonin levels. Serotonin is a neurotransmitter, or more simply, a chemical messenger in our brains, that is responsible for stabilizing our moods. Research suggests that the decrease in exposure to sunlight can also reduce serotonin activity in our brains (McMahon et al., 2014). When serotonin levels go down, our brains have a harder time balancing our emotions, which puts us at a greater risk for developing depressive moods. 

• An increase in melatonin. Do you catch yourself wanting to sleep in during a rainy day? Or maybe take the day off when the skies are gray to snuggle under the blankets and binge-watch your favorite show on Netflix? A change in melatonin might be causing this. Melatonin is a hormone found in the pineal gland of our brains and plays a role in our level of sleepiness throughout the day. When it’s dark outside, melatonin production increases, making us sleepier (Miller, 2005). The transition to colder temperatures and shorter days can influence melatonin levels to increase, which is why fatigue and lethargy are often associated with Seasonal Affective Disorder. 

• Disruption of the circadian rhythm. Our circadian rhythm, or our biological clock, is our body’s natural process of monitoring our sleep-wake cycle. As the season changes into winter, the nights become longer, which affects the balance of our sleep-wake cycle. This disruption is further influenced by a change in our serotonin and melatonin levels, which can delay our sleep patterns and alter our daily routines (Lewy et al., 2009). Such a change may make it more difficult to regulate our moods, leading to feelings of depression.

Risk Factors for Seasonal Affective Disorder
While anyone can experience Seasonal Affective Disorder, like most other conditions, some of us may be more likely to experience symptoms of SAD. In summary, females and younger people have an increased risk of developing symptoms of Seasonal Affective Disorder. Below you will find a more detailed overview of risk factors.

• Sex differences. Female-identifying folks tend to be impacted by Seasonal Affective Disorder nearly four times more than their male counterparts (Kurlansik & Ibay, 2012). 

• Age. Young adults, typically between the ages of 18-30, have an increased likelihood of displaying symptoms of Seasonal Affective Disorder (Galima, Vogel, & Kowalski, 2020). 

• Family History. If you have a parent, grandparent, or other close relatives who have previously experienced Seasonal Affective Disorder, or other depressive disorders, you may have a higher predisposition of experiencing SAD (Galima, Vogel, & Kowalski, 2020).  

• Geographic Location. Interestingly enough, where you live can impact your likelihood of developing Winter-Seasonal Affective Disorder. If you happen to call tropical islands and countries close to the equator your home, you likely have the advantage of a lower risk of developing Seasonal Affective Disorder symptoms. However, if you live in the hustling and bustling cities of the American Northeast or are used to shoveling several inches of snowfall from your driveway each year, you most likely live further from the equator. And the latitudinal position of your home determines your exposure to sunlight (Galima, Vogel, & Kowalski, 2020). So, those of us that live further North or South of the equator may want to keep an eye out for Seasonal Affective Disorder symptoms, especially during the winter months.​​

Whether you are someone (or know someone) whose psychological health is negatively affected in the winter or summer, several of the symptoms of Seasonal Affective Disorder are similar regardless of when your onset of SAD occurs (Melrose, 2015). Below you will find a list of these signs.

• Persistent sadness. This type of sadness is not momentary or temporarily triggered by your favorite character dying in a movie (but of course, we all know the pain and tears that can come with this situation). Persistent sadness may include feeling hopeless, unenergetic, and be accompanied with crying, for most of the day and occurring almost every day. This type of mood typically lasts longer than two weeks. 

• Changes in energy levels and interests. Maybe you’re a big sports fan like me, and suddenly find no joy in watching your team play, or you love to read and somehow don’t have the energy to pick up a book off of your bedside table anymore. Seasonal Affective Disorder might be influencing these changes. When you begin to lose interest in activities you enjoy or are having a harder time crossing off the tasks on your to-do list, you may want to reflect on whether your body and well-being are affected by the changing seasons. 

• Altered sleep patterns. Remember our conversation about melatonin and circadian rhythms? Here’s the effect of those changes. Those of us experiencing SAD may find ourselves sleeping more than normal or having trouble sleeping altogether.

• Shifts in behavior. When our moods, sleep, and energy levels change, they may have an effect on our behaviors, too. Some common changes in behavior may include difficulty concentrating, increased irritability, and removing yourself from social situations. 

As we now know, Seasonal Affective Disorder can have a winter or summer onset. While the symptoms listed above tend to develop no matter what season of the year you experience Seasonal Affective Disorder, there are some distinct differences that are worthy of taking into account. 

Winter-Seasonal Affective Disorder Symptoms​

• Sleeping more than normal
• Craving foods high in sugar and carbohydrates (e.g., wanting to eat the whole pumpkin pie rather than a slice (or two) during a holiday dinner)
• Gaining weight due to an increased appetite 

Summer-Seasonal Affective Disorder Symptoms

• Insomnia, or difficulty sleeping at night 
• A reduction in food intake or skipping meals altogether 
• Losing weight due to a decreased appetite 

Research has shown a few options for treatment for Seasonal Affective Disorder. These approaches include therapy, medication, and light therapy—and sometimes, a combination of all three of these techniques (Kurlansik & Ibay, 2012).  

Psychotherapy for Seasonal Affective Disorder
Psychotherapy, otherwise known as talk therapy, is exactly what it sounds like. It may not be identical to how TV characters lay on the big couches in their therapist’s office explaining to them their life dilemmas in detail, but talking about problems and emotions to a therapist can look similar. Seeking out help from a therapist may not always be the easiest step for us, but psychological professionals are trained in various therapy styles that can help aid us in our journeys to recovery and better holistic wellness when dealing with SAD. 

One of the most common therapy techniques psychologists use is Cognitive-Behavioral Therapy (Melrose, 2015). Cognitive means relating to thoughts, while behavioral refers to actions. Simply put, cognitive-behavioral therapy focuses on how we can change negative thoughts and behaviors to positive ones, therefore elevating our mood. 

Cognitive-Behavioral Therapy for Seasonal Affective Disorder
But what exactly does this look like in practice? Let’s say you experience Seasonal Affective Disorder symptoms during the wintertime and you hate the thought of tolerating cold weather. When you look at the snow falling outside, you feel upset that you are unable to go on your morning walk with your dog and smell the fresh air while soaking in the sun on your skin. The lack of physical activity and quality time spent with your fur baby is making you feel irritable. 

A therapist practicing a cognitive-behavioral technique might ask you what alternatives might help you conquer this challenge. Maybe you grab a big coat for yourself (and a sweater for your dog) and make snow angels in the front yard. Perhaps you plan a quick and easy getaway to a slightly sunnier location. Or instead, maybe you come up with a list of exercises you can do in the comfort of your own home that elevate your heart, and similarly, your mood. 

Cognitive-behavioral therapy allows you to speak to a professional to recognize the harmful thought patterns that may be occurring and collaborate together to find actionable ways to change negative behaviors into more meaningful and positive ones. 

As we know, a dip in serotonin in our brains can lead to the destabilization of our moods. The antidepressant medication works to reverse this effect, thus allowing our brains more control in emotion (or mood) regulation. 

It is important to note here that like any other medication, it is recommended to ask your doctor for medications that are best for you and your body. Sometimes, antidepressants can present side effects such as nausea, changes in bowel movement, an upset stomach, and anxiety. When considering medication as a primary option or supplement for your treatment with Seasonal Affective Disorder, it may be a good idea to speak to a healthcare provider about any questions or concerns you may have prior to beginning treatment.

You may be wondering how light therapy works, especially during the wintertime when light isn’t exactly abundant in supply. Light therapy, also known as phototherapy, is operated through a light box. Yes, you read that correctly—it is indeed a box of special light while eliminating harmful ultraviolet rays, to mimic natural daylight. For example, red light therapy may be helpful.

The process of light therapy is relatively simple once you receive a light therapy box from a medical provider or purchase your own. Research suggests that those of us who struggle with Winter-Seasonal Affective Disorder, in particular, turn on our light box first thing in the morning and sit in front of it for 20-60 minutes every day. 

Whether you are getting ready for work, making your breakfast, or taking a few moments to practice some meditation, having a light box in front of you may improve your mood. What does this box do to your brain, you ask? Light therapy has shown success in reducing your melatonin production while increasing your serotonin level. In simple terms, light boxes may aid in making you a little less tired and a bit more inspired, while turning your feelings of sadness into feelings of gladness. 

Light therapy may also include some side effects, such as eyestrain, headaches, and difficulty sleeping. For those of us who may have a diagnosis for Bipolar Disorder, in particular, it is recommended to discuss light therapy options with your medical provider, as this technique may interfere with treatment for Bipolar Disorder.

• Keep your diet in check. Whether it’s cold outside and we’re reaching for a warm midnight snack, or we’re losing the motivation to make a meal when it’s too bright out, having a balanced diet can help us manage symptoms of Seasonal Affective Disorder better. In the wintertime, we experience a reduction of Vitamin D due to a lack of sunlight (Melrose, 2015). Some foods that can help us combat this include eggs, salmon, and fruits and vegetables, such as oranges or leafy greens. Don’t seem to have the energy to make a meal? It might help to ask a friend, family member, or partner to cook a healthy snack together. Not only can this help you feel properly satiated, but you may even benefit from some social support from a loved one.

• Try to stay active. Sometimes the weather outside may be in freezing temperatures. Other times, there’s not enough air conditioning to keep you from sweating out the heatwave. It may not always be the best day to go outside, but we still have some options to stay active inside. Whether you have a gym membership or put on your favorite yoga video on YouTube, getting your body moving can alleviate lethargy and sadness caused by SAD thanks to the endorphins you release when you exercise. And hey, if the weather isn’t so bad and you have a few moments to step out, a nice stroll in the park or quick run may also help. 

• Invite in social support. If you’re anything like me and feel thrilled with the opportunity to spend time with people, prioritizing social support may help elevate negative emotions or thoughts that you may have. Whether it’s meeting a friend for coffee, having a movie night with your family, or even FaceTiming a loved one to chat, social support not only lifts our spirits but can make us feel less alone when dealing with depressive moods. ​

• Emotion: Definition, Theories, & Examples
• Emotional Dysregulation: Definition, Examples, And Tips
• ​Mood Disorders: Definitions, Symptoms, & List
• ​Blue Light: Effects on Sleep & Health
• Benefits of Vitamin D: For Men, Women, & Mental Health
• Mental Health: Definition, Awareness, & Resources

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• Rosenthal, N. E., Sack, D. A., Gillin, J. C., Lewy, A. J., Goodwin, F. K., Davenport, Y., … & 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. ​