Seasonal Affective Disorder and Sleep
Changing seasons are a natural part of life each year: fall turns to winter, winter to spring, spring to summer, and summer back to fall again. However, for some people, the change in seasons triggers the onset of a specific form of major depressive disorder, which can become a debilitating condition for those who suffer from it.
This condition is referred to as Seasonal Affective Disorder, or SAD. SAD can impact many parts of a person’s life, including mood, appetite, the ability to work, the ability to interact with others in a healthy way, and even basic everyday functionality.
One thing that is often affected in the life of a person with SAD is sleep. Because of the specific way that SAD functions (in large part because of the effects it has on the natural circadian rhythms and the production of both serotonin and melatonin,) SAD patients often report significant sleep disturbances. These sleep disturbances can, in turn, exacerbate the other symptoms of the disorder, which can quickly spiral out of control.
Though SAD can be very serious, there are things people can do to address the condition and the accompanying sleep disorders and to alleviate the struggles they face every year. The key to easing the negative effects of SAD is learning about what causes the disorder, how it works, and how it affects sleep, and taking steps to move forward. In this article, you’ll find a deep dive into the inner-workings of SAD, sleep, and potential treatments for a healthier, happier life.
What is Seasonal Affective Disorder?
Seasonal Affective Disorder (or SAD) is a specific type of depression related to changes in seasons. The course of the disorder is cyclical: symptoms last for one season (fall/winter or spring/summer), and go into remission in the next. For most people with Seasonal Affective Disorder, symptoms set in around the fall and last through the winter months, though a small percentage (around 10%) of SAD sufferers experience onset around the spring and depression throughout the summer. In either case, symptoms set in around the same time every year, tend to last around the same amount of time, go into remission around the same time, and return around the same time.
Seasonal Affective Disorder is relatively common, affecting approximately 10 million Americans (around 14%) and 4-6% of all people every year. The symptoms and severity of Seasonal Affective Disorder can vary, but in many cases, patients can be severely incapacitated and unable to function during the affected time period.
SAD occurs four times more often in women than in men, with an average age of onset between 18 and 30 years old. Generally, it affects younger adults more than older adults, and like other forms of clinical depression, it occurs more frequently in people who have a family history of the condition, or of any Major Depressive or Bipolar Disorder. Additionally, it appears that the farther a person lives from the equator, either to the north or the south, the higher their risk of developing Seasonal Affective Disorder. This is thought to be because of decreased sunlight during the winter months (which exacerbates winter-pattern SAD) and longer days during the summer months (which exacerbates summer-pattern SAD.)
Researchers have faced several issues in calculating the prevalence of Seasonal Affective Disorder. One issue is the fact that it tends to go unreported, and is therefore likely underdiagnosed. It is also considered difficult to diagnose in those who do report symptoms, because it is often comorbid with other mental health disorders (including major depressive disorder, bipolar disorder, attention deficit disorder, alcoholism, and eating disorders), as well as subtle or significant hypothyroidism (or, a decrease in thyroid function), which have similar symptoms and can therefore prevent diagnosis of SAD.
It is very important to remember that Seasonal Affective Disorder is not just the “winter blues” or fatigue from the dog days of summer. Rather, SAD is a form of chronic, recurrent depression and disordered mood, and should be treated seriously as such.
Symptoms of Seasonal Affective Disorder
As defined in the DSM-IV, Seasonal Affective Disorder is a specific form of Major Depressive Disorder that displays a seasonal pattern.
Therefore, in order to be diagnosed with SAD, a person must both meet the criteria for major depression and must experience those symptoms in a recurring seasonal pattern for at least two years.
The symptoms of major depression include:
- Feeling depressed for the majority of the day, on most days.
- Feeling worthless, useless, or otherwise self-loathing
- Unusual feelings of guilt
- Hopelessness about the present and the future.
- Low energy or sluggishness
- Loss of interest in previously enjoyable interests, subjects, experiences, and/or activities
- Changes in appetite (including loss of appetite, overeating, binge eating, and otherwise disordered eating patterns)
- Agitation and irritability
- Difficulty concentrating
- Difficulty socializing and social withdrawal
- Lack of motivation
- Reduced libido
- Sleep problems (including insomnia, sleeping too little; hypersomnia, sleeping too much; and/or parasomnias, other irregular sleep disturbances)
- Frequent thoughts of death or suicide.
Seasonal Affective Disorder does tend to exhibit specific types of depressive symptoms more than others. Further, Winter-Pattern SAD tends to exhibit different types of depressive symptoms than Summer-Pattern SAD.
Though these specific symptoms are more common in people with winter-pattern SAD and summer-pattern SAD respectively, people with SAD can also experience many of the other common symptoms of Major Depressive Disorder in the same seasonal time period. In addition, the severity of Seasonal Affective Disorder symptoms vary from person to person, with some people being affected much more severely than others. For many, though, the symptoms of Seasonal Affective Disorder can be just as serious and detrimental to basic life functions as year-round major depression.
Causes of Seasonal Affective Disorder
The exact cause of Seasonal Affective Disorder is unknown. However, there are a number of theories about what factors may contribute to SAD, some pertaining to winter-pattern SAD, some to summer-pattern SAD, and some to both.
It is important to point out that because Winter-Pattern Seasonal Affective Disorder is much more prevalent than Summer-Pattern Seasonal Affective Disorder, the majority of research done on SAD has been winter-pattern based. It has been theorized that some of the same things that may cause winter-pattern SAD can also factor into summer-pattern SAD (especially when it comes to sensitivity around circadian rhythm changes). However, for summer-pattern SAD, a number of additional causes may come into play. They include:
- Sensitivity to Heat: Studies have linked heat to depressed and agitated moods, as well as increased risk for mental health emergencies. This is thought to be caused in part by heat stress, which is the tax that heat has on individual peoples’ bodies and minds. It is possible that people with Summer-Pattern Seasonal Affective Disorder have problems sustaining homeostasis, or regulating internal temperature despite external factors. This would lead to a lower tolerance for heat and a higher risk for heat stress, which may be a factor in the development of summer-pattern SAD symptoms.
- Sensitivity to Light: While light therapy is often used to treat winter-pattern SAD (as we’ll explore below), sensitivity to light may actually be a significant factor in developing summer-pattern SAD. While decreased light might alter the production of melatonin and serotonin in a person with winter-pattern SAD, increased light might also alter the production of those chemicals and proteins in people with summer-pattern SAD. An increase in the “wakefulness” trigger (light) in those with summer-pattern SAD may produce some of the key symptoms of that subtype of the disorder, such as agitation, insomnia, and restlessness.
- Social Factors: Like winter-onset SAD, there are a number of things about the social structure of summer that may contribute to the onset of depression in a pre-disposed person. For many people (especially school-aged people and those who work jobs with summer breaks), summer means the disruption of routine, which can trigger depressive episodes. There is also often significant pressure during the summer months to be out “having fun”, and making the most of the warm weather. For someone who has summer-pattern SAD, this can exacerbate existing symptoms.
How SAD Affects Sleep
Seasonal Affective Disorder and sleep have a complex, intertwined relationship, such that it is almost impossible to think about one without thinking about the other. SAD both causes and exacerbates many sleep-disturbance-related symptoms.
People with winter-pattern SAD and summer-pattern SAD generally experience different types of sleep disturbances--hypersomnia and insomnia, respectively--though sometimes they can experience both. In either case, sleep has been shown to be a major affected area in the lives of most people with Seasonal Affective Disorder.
In many ways, the relationship between Seasonal Affective Disorder and sleep is similar to the relationship between other types of Major Depressive Disorder and sleep. Like people with Major Depressive Disorder, people with SAD are more likely to experience “long” or “short” sleep (more than 9 hours, or fewer than 6). They also get less restorative, efficient sleep, and spend less time in deep sleep, and are significantly more likely to experience frequent nightmares and subsequent frequent awakening.
There are also ways in which the specific mechanisms of Seasonal Affective Disorder affect sleep and vice versa. Three of the main factors that go into SAD are changes in circadian rhythm, serotonin regulation, and melatonin production, all of which play a role in sleep.
When the body’s circadian rhythm is disrupted, or when a person is having difficulty adjusting their circadian rhythm to seasonal change, sleep is affected. In people with Winter-Pattern Seasonal Affective Disorder, this means that less light getting picked up by the circadian alerting system during the winter causes the body to signal less wakefulness, and allow sleepiness to take hold. This is one reason why approximately 80% of people with Seasonal Affective Disorder report hypersomnia, or oversleeping. Additionally, many people with winter-pattern SAD spend much more time in bed than is typical, which actually causes people to feel overly sleepy throughout the day.
In people with Summer-Pattern Seasonal Affective Disorder, this circadian disruption is also important, An increase in light during the summer may over-stimulate the circadian alerting system in those patients, causing it to signal wakefulness inappropriately. This may lead to a person with summer-pattern SAD being unable to relax, and to experience restlessness, irritability, anxiety, and insomnia.
In addition, people with Seasonal Affective Disorder may be sensitive to changes in circannual rhythms--other seasonally-based changes in the external world, such as temperature, weather, and barometric pressure. These changes can also influence sleep in people with SAD. For instance, as mentioned above, people with summer-pattern SAD may find it more difficult to obtain homeostasis in the heat and humidity of the summer, which may contribute to the high rates of insomnia reported in that subset.
When it comes to the neurochemistry of Seasonal Affective Disorder, both serotonin and melatonin-related issues can affect sleep, especially for people with winter-based SAD. As aforementioned, people with winter-based SAD have been shown to have higher levels of SERT (and thus a lowered effect-level of serotonin) during the winter months, which can cause depressive symptoms. These depressive symptoms may, in themselves, cause sleep disturbances, especially hypersomnia, but also insomnia and various parasomnias. Meanwhile, overproduction or over-sensitivity to melatonin can make people with winter-based SAD even more prone to hypersomnia.
All of these sleep disturbances can exacerbate the symptoms of SAD, which in turn can worsen the sleep disturbances themselves, creating a sort of vicious cycle.
Help for Managing SAD
Having explored the causes, symptoms, and sleep effects of Seasonal Affective Disorder, it’s clear that the disorder can be quite serious, and may even seem overwhelming. However, SAD is treatable: there are many existing treatment methods available for people with SAD, for both generalized and sleep-related symptoms. Moreover, addressing the general symptoms of SAD will affect the sleep-related symptoms, and vice versa. Like most treatment regimens for major depressive disorders, each approach will be slightly different and should be catered to a person’s individual needs. However, there are many steps that a person with SAD can take to start the recovery process.
Light Therapy Treatment for SAD
Light Therapy Treatment is one way to treat Seasonal Affective Disorder (specifically, winter-pattern SAD). It involves being exposed to bright light, which is supposed to make up for the lack of light exposure during the winter months. Otherwise known as bright light therapy or phototherapy, forms of this treatment have been used to address mood disorders for centuries, but a more medically supported, research-based method has been used to treat SAD in recent times.
During light therapy, a patient will sit near a device that gives off bright light--usually, at least 10,000 lux of cool-white fluorescent light, which is around 20 times brighter than regular indoor lighting-- and either read, or work, or just relax. These devices used to be available exclusively in medical offices, but can now be purchased and used within a person’s home or workplace.
Like all treatments, the effectiveness of light therapy varies from person to person. However, when it comes to Winter-Pattern Seasonal Affective Disorder, it has been found effective in reducing symptoms in a sizable percentage of patients. One study, which utilized data from 14 research centers studying 322 patients over five years, found that exposure for at least 2 hours daily for 1 week resulted in significant levels of remission of SAD symptoms.
If you’re interested in trying out a SAD lamp, it’s important to do your research. SAD lamps for individual use aren’t yet regulated by the FDA, so it’s important to read expert-based reviews and compare your options carefully. This guide from the Mayo Clinic provides a good summary of what to look for and why.
In addition, it is definitely recommended that you consult with your doctor about light therapy, specifically what type to seek out, how to use it, and if you at risk for any complications. For instance, if you suffer from bipolar disorder, increasing exposure to a lightbox too quickly or using it for too long may induce mania, while people with eye problems such as glaucoma and cataracts may want to avoid sustained intense light exposure altogether. In any case, consulting with your doctor about this decision is key.
SSRIs and Antidepressants
Another commonly prescribed treatment for Seasonal Affective Disorder is medication, specifically SSRIs and other forms of antidepressants.
SSRIs (or, Selective Serotonin Reuptake Inhibitors) are the most commonly prescribed type of antidepressant and are most frequently prescribed for Seasonal Affective Disorder. They work by blocking the reabsorption of serotonin into the brain. This is particularly helpful when treating SAD, since one of the main potential causes is the overproduction of SERT, which increases serotonin reabsorption and reduces the positive effects of serotonin. The most common SSRIs are Citalopram (Celexa), Escitalopram (Lexapro), Fluoxetine (Prozac), Paroxetine (Paxil), and Sertraline (Zoloft), all of which can be prescribed to treat SAD.
In addition to SSRIs, another class of antidepressants called bupropion (including the brands Aplenzin and Wellbutrin XL) are approved by the FDA to treat Seasonal Affective Disorder. Bupropion works by inhibiting the reabsorption of serotonin, as well as dopamine and norepinephrine, which are also important neurotransmitters when it comes to mood and sleep.
All medications have potential side effects and interactions, so you should absolutely consult your doctor to find out which of these options, if any, may work for you.
Seasonal Affective Disorder patients, like many patients with Major Depressive Disorders, often benefit from psychotherapy.
There are many types of therapy that can be useful to SAD patients, but the one that is most commonly suggested is Cognitive Behavioral Therapy, or CBT. CBT helps patients identify negative thoughts and harmful patterns and replace them with positive ones through a process called “behavioral activation”. In fact, there is a form of CBT that is specifically adapted for use with SAD (known as CBT-SAD), which uses behavioral activation to help a person with SAD identify pleasurable or helpful activities in order to improve the ability to cope during affected months.
Other types of therapy that are sometimes used to treat SAD include Somatic Therapies (such as Hakomi and Somatic Transformation), which use body-centered practices to focus on the relationship between the body and the mind, and Psychodynamic Therapies, which focus on redirecting maladaptive coping strategies from a person’s past.
Appetite is often affected by SAD, causing people to either overeat (often in the case of winter-pattern SAD), or have trouble eating (often in the case of summer-pattern SAD.)
Though more research is needed when it comes to the potential effects of diet on SAD symptoms, there are a number of theories about dietary changes that may be helpful. One theory has to do with omega-3 fatty acids.
Omega-3 fatty acids are a key family of polyunsaturated fats. They are an integral building block of cell membranes throughout the body, and therefore affect the cell receptors within those membranes. In doing so, they play a key role in making hormones that regulate vital body functions like blood clotting, contraction and relaxation, and inflammation. They have been shown to prevent heart disease and stroke, and may also help control lupus, eczema, rheumatoid arthritis, and cancer.
In addition, omega-3’s appear to help regulate mood and maintain healthy levels of dopamine and serotonin. Having a deficit of omega-3 fatty acids has been linked to depression, and specifically to SAD.
While the body can make most types of fats it needs, it cannot make omega-3 fatty acids from scratch. Rather, these essential fats must be taken in from food. It has been suggested that regularly consuming foods rich in omega-3’s may reduce a person’s risk of developing SAD and experiencing SAD symptoms. People with SAD may benefit from introducing foods with omega-3’s--such as oily, fatty fish like mackerel, herring, salmon, sardines, and anchovies, as well as flaxseed, help, canola, and walnut oils and nuts--into their diets.
It is also especially important for people with winter-pattern SAD to watch out for increased carb and sugar cravings. It’s not exactly known why people with winter-pattern SAD crave carbs during affected seasons, but one reason may be decreased serotonin levels. Carbohydrates and sugars promote the production of serotonin, and, when faced with reduced serotonin, the body may seek that out in the form of a carb craving. Unfortunately, some sweets and simple carbohydrates (like doughnuts and white bread) quickly raise blood sugar levels and trigger a spike in insulin, which causes the blood sugar to rapidly metabolize. This results in the “sugar crash” in the immediate aftermath of a simple carb binge, which can exacerbate SAD symptoms and increase irritability and fatigue.
However, some carbs can actually help promote serotonin production without causing the spike and crash in blood sugar levels. People with SAD may benefit from choosing carbohydrates with little fat and low protein, such as popcorn, pretzels, shredded wheat squares, or low-fat biscotti for snacks, and lentils, brown rice, and potatoes during meals.
There are many supplements used by people with SAD to treat symptoms. The main supplement suggested is Vitamin D, which may be deficient in some SAD sufferers. Vitamin D deficiency has been linked to depression and mood disorders, and Vitamin D absorption (which primarily occurs through exposure to UV sunlight) often varies by season. The effectiveness of Vitamin D supplements in treating SAD has been debated, but the general consensus is that it can be helpful in some patients. It is estimated that approximately 7 out of 10 Americans don’t get enough Vitamin D, especially during the winter. Your doctor can help test your Vitamin D levels and establish whether or not you may need a supplement.
In addition, some research has been done into the use of melatonin supplements in the treatment of SAD. Some SAD patients experience problems regulating their melatonin production (either producing too much or too little). Though there needs to be more research done on this topic, some studies suggest that melatonin may help improve sleep and daytime vitality in some SAD patients, specifically in patients with milder symptoms. Other supplements used by SAD patients include:
- 5-HTP: Otherwise known as 5-hydroxytryptophan, a nutrient supplement that may increase serotonin levels.
- Tyrosine: A supplement that may help the brain produce catecholamines (which promote mood health) and may reduce stress.
- SAM-e: Otherwise known as S-adenosyl-methionine, a supplement that may improve mood by encouraging the production and sensitivity to serotonin and dopamine.
- Folic Acid: A B-Vitamin that may be used by the body to create serotonin.
It is very important to remember that supplements, like prescription medications, are drugs, and may have side effects, interactions with other medications, or general health repercussions. It is essential that you discuss adding any potential supplements into your SAD care regimen with your doctor before doing so.
Though a person suffering from SAD symptoms may find it very difficult to drum up the motivation to exercise, getting and staying active is a very effective tool for fighting SAD. Studies have shown that getting at least 30 to 60 minutes of exercise each day can significantly reduce SAD symptoms, and can also reduce the risk of symptom recurrence.
Even if it feels hard to get started, there are proactive things you can do to begin and maintain a regular exercise routine. Make a specific time for exercise every day, and stick to it. Ask friends to join you in exercise activities, or enlist their help for accountability check-ins. Try to find a form of exercise that you actually enjoy (for instance, kickboxing, swimming, dance, or whatever else you find invigorating), and mix up exercise styles so you don’t get bored. Take classes at a gym or exercise studio, and, if possible, hire a personal trainer to keep you going.
Natural Light Exposure
Since increased or decreased exposure to natural light clearly has a key role to play in Seasonal Affective Disorder, one commonly utilized treatment is approaching that deficit or surplus of natural light head-on.
For people with winter-pattern SAD, spending at least an outside during the day, under direct, natural sunlight, has been shown to improve self-reported SAD symptoms. Incorporating an outdoor walk into your schedule before work, or during your lunch break, can mitigate the effects of reduced sunlight exposure.
Mindfulness and Meditation
Mindfulness and meditation techniques are used to treat many forms of Major Depressive Disorder, including SAD. Studies have shown that mindfulness and meditation can be helpful in mitigating SAD symptoms in some patients. There are many forms of mindfulness practices and meditation techniques commonly used to treat SAD. They include:
- Relaxation-based Movement Techniques, like yoga or tai chi
- Transcendental Meditation, a subtype of meditation developed to increase energy levels and improve depression and anxiety.
- Loving-Kindness Meditation, which helps create an attitude of love and kindness toward yourself and others.
- Mindfulness Meditation, which focuses on moment-to-moment awareness of the present, the use of breath, and attention to the body and can ease depression, anxiety, and stress.
Improved Sleep Habits/Hygiene
Of course, one of the most important things you can do to help alleviate your SAD symptoms is to regularly get a healthy amount of restorative, restful sleep. Though people with SAD do experience unique sleep problems, there are also specific things they can do to improve their sleep habits, and therefore improve their chances of getting a good night’s sleep.
For people with winter-type SAD, it’s especially important to fight the inclination toward hypersomnia. Establish a set bedtime every night, and set an alarm for the morning that you are unable to sleep through. Make sure not to spend any more time in your bed than is necessary, as this may encourage oversleeping and other disordered sleep patterns.
For people with summer-type SAD, who experience more insomnia, it’s important to create a comfortable, stimuli-free sleep environment. Invest in blackout curtains, soundproofing, and a high-powered air conditioning system to keep you as cool as possible and to limit increased UV exposure.
For those with either sort of SAD, it’s best to stay away from caffeine or alcohol before bed, to limit screen time right before sleeping, and to establish a nightly routine that you can follow to help your body adjust to a healthy sleep pattern.
If serious sleep problems continue, consult your doctor about possible underlying causes and/or additional sleep aids.
Learn More About SAD and Sleep
Major Depressive Disorders like SAD can often feel overwhelming and insurmountable. It may feel like you’re all alone in the struggle, and there’s no one to turn to. However, you are not alone. There are many people out there struggling like you, and many resources to help.
- National Suicide Prevention Hotline: If you are struggling with feelings of suicidal ideation, this is an excellent, judgment-free hotline. Speak to a trained, empathetic expert about what you’re going through, and how to get help. Hotlines are available in English and Spanish, with options for the hard of hearing, and a text messenger function.
- SAMSHA National Helpline: This helpline, run by the Substance Abuse and Mental Health Services Administration, is a free, confidential, 24/7, 365 day a year hotline for people struggling with any mental health or substance abuse issues. They have resources both for individuals and families, and can provide referrals to local organizations, support groups, medical professionals, and treatment facilities.
- SAD Coping Strategies: A list of coping strategies for people with Seasonal Affective Disorder.
- Mayo Clinic SAD Fact Sheet: A comprehensive, up-to-date information resource about SAD.
- Helping a Loved One with SAD: A compassionate, supportive source of support for the loved ones of those living with SAD.
- APA Psychologist Locator: The American Psychological Association’s finder tool for local, qualified mental health professionals.
- SAD and Kids: For children experiencing SAD, and the parents of kids with SAD.
- Seasonal Affective Disorder Support Group: This Facebook-based group has over 7,000 members, and serves as a place for people to talk about SAD with others who understand.
- R/Winterblues: A fairly active subreddit for people with SAD to share information and resources.
- Depression and Bipolar Support Alliance: This database of support groups includes a number of online and in-person groups for SAD support.