Understanding Seasonal Affective Disorder

As the days become shorter and temperatures continue to drop, many people begin to experience noticeable changes in their mood, appetite, sleep patterns, and energy levels. If these changes occur every year around the same time, typically around fall or winter, a possible explanation may be seasonal affective disorder (SAD), a condition more commonly known as seasonal depression.

For most people, SAD occurs during the colder months of the year, typically starting around fall or winter, and lasting until late spring to summer. However, some people may experience seasonal depression in the warmer months of the year, starting in the spring and lasting through fall. Whether you experience SAD during the summer or winter months, it’s important to understand that, if left untreated, SAD can increase your risk of other mental health conditions, including a substance use disorder (SUD).

What Is Seasonal Affective Disorder?

Feeling sad for brief periods of time is a normal part of life. Oftentimes, feeling sad is an expected response to events such as the loss of a loved one, financial troubles, or problems at work or school. While these responses are normal, when feelings of sadness, loneliness, or low self-esteem persist for longer than normal, it may be a sign of a depressive episode.

Before exploring the relationship between SAD and SUDs, let’s cover some general information about SAD. According to the Diagnostic Statistical Manual of Mental Health (DSM-5), a guidebook used by mental health professionals in the assessment and diagnosis of mental health disorders, SAD is a recurring form of depression (major depressive disorder) with seasonal pattern. Per the DSM-5, to meet the criteria for SAD one must:

  • Experience symptoms of major depression, hypomania, or mania. These episodes must occur during specific seasons (i.e., only during the winter months or the summer months) for at least 2 consecutive years
  • Experience full remission of symptoms in between the seasons.

In some cases of SAD, these episodes can become severe and affect how you think, feel, and even perform daily activities.

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When Does SAD Occur?

For most cases of SAD, symptoms typically begin and end in specific seasons. While some people experience SAD in the spring or summer, for most people SAD commonly begins in the fall through the winter. As previously mentioned, if symptoms of depressive episodes do not recur during these specific times of year, it may be the case that you are experiencing major depressive disorder rather than SAD.

Symptoms of SAD typically last about 40% of the year, which, for most people, runs between October or November to March or April. In all cases, the symptoms of SAD are not present during other seasons and will begin with the changing of the seasons.

What Are The Symptoms Of SAD?

The National Institute of Mental Health (NIMH) reports that most symptoms of fall or winter-based SAD center around an unhappy mood and decreased energy. While not every person will experience all the symptoms of SAD, some of the most common include:

  • Irritability
  • Frequent crying spells
  • Day time fatigue and lethargy
  • Difficulty focusing and concentrating
  • Loss of interest and pleasure in activities
  • Increased sleeping or oversleeping
  • Isolating and social withdrawal
  • Craving sugar and carbohydrates
  • Overeating
  • Weight gain
  • Physical problems, such as headaches
  • Thoughts of suicide

Conversely, spring or summer-based symptoms of SAD typically present symptoms that are the opposite of fall or winter SAD, and include:

  • Poor appetite
  • Weight loss
  • Insomnia
  • Restlessness
  • Agitation
  • Anxiety
  • Violent tendencies

The Relationship Between SAD And Substance Use

As our understanding of addiction and mental health continues to progress, we continue to learn more about the relationship between the two. Through years of addiction and mental health-related research, experts in the field have concluded that the presence of a mental health condition increases a person’s likelihood of developing a substance use disorder by nearly 50%, and vice versa.

This relationship between mental illness and addiction can become even more apparent during times of the year in which we experience more stress, whether it be financial, familial, or work-related. For many, this increase in stress typically occurs during the winter months, where holidays, family gatherings, and shorter days can all take a toll on our mental health.

For example, individuals who are experiencing symptoms of SAD are typically lethargic, fatigued, socially withdrawn, and have a loss of interest in activities they usually enjoy. In an attempt to manage these symptoms, people self-medicate and gravitate towards drugs that are stimulating like cocaine, methamphetamines, or ecstasy.

Additionally, during the holidays people can experience depression, anxiety, loneliness, insomnia, sugar cravings, and overeating. As an unhealthy coping strategy, many people reach for alcohol as quick fix to numb the pain, ease the discomfort of social and familial gatherings, help with sleep disturbance, and to satisfy sugar cravings. What people do not realize is that when they ingest more sugar, they create spikes and dips in their blood sugar levels. When blood sugar levels drop below the initial baseline it creates more intense cravings for sugar and/or alcohol.

Mental health providers typically report seeing an influx in new patients around the beginning of the year. While many of these patients are likely the result of New Year’s resolutions, a significant portion of those are people experiencing SAD. Among those seeking treatment for SAD is a growing number of patients who report a co-occurring substance use disorder.

What Causes SAD?

Researchers do not completely understand the causes of SAD; however, they have discovered the following links:

Decreased Serotonin Levels

People with SAD will typically have reduced levels of serotonin, a brain chemical that helps regulate mood. Sunlight is one of the major ways the body controls serotonin levels; however, in people with SAD, this regulation does not function properly, resulting in decreased serotonin levels in the winter.

Another reason many people with SAD have lower serotonin levels, specifically those with fall or winter SAD, is due to increased time spent indoors. For those living in colder climates, the winter months, combined with the shorter days, limits the amount of outdoor time people have. This means that the body doesn’t produce as much serotonin as it normally would, which can lead to feelings of sadness or loneliness.

Too Much Melatonin

It is believed that people with SAD produce too much melatonin, a hormone that is integral to maintaining the normal sleep-wake cycle. The body makes more melatonin when it is dark and slows production during the daytime. Overproduction of melatonin can increase sleepiness, which can lead to chronic fatigue, lethargy, decreased appetite, and many other symptoms associated with SAD.

Vitamin D Deficiency

Vitamin D is an essential nutrient found in many of the foods we commonly eat. It’s also produced by the body when exposed to sunlight. Vitamin D promotes healthy serotonin activity. When there is less sunlight in the winter, people with SAD may have lower vitamin D levels, which may negatively affect serotonin activity.

People with SAD also tend to experience either a decrease in appetite or cravings for foods like carbohydrates or sugars, both of which tend to be low in vitamin D. This can lead to decreased levels of vitamin D, which can also lower the body’s serotonin levels.

Disruption In Daily Rhythms

Both serotonin and melatonin help to maintain the body’s daily rhythm that is tied to the seasonal night-day cycle. In people with SAD, the changes in serotonin and melatonin levels disrupt the normal daily rhythms. As a result, people can no longer adjust to the seasonal sunlight changes, leading to sleep, mood, and behavior changes.

Circadian Rhythm

Circadian rhythms are responsible for a variety of important functions: daily fluctuations in wakefulness, body temperature, metabolism, digestion, hunger, the formation of long-term memories, the timing of growth hormone secretion, and body healing.

An irregular circadian rhythm can have a negative effect on the body’s ability to sleep and function properly, which can result in mood disorders such as depression, anxiety, bipolar disorder, and SAD.

Who Is At Risk For SAD?

Approximately 5% of adults in the U.S. experience SAD. There are many different risk factors that may put someone at risk for developing SAD. Some of these risk factors may be genetic, and largely out of your control, while others may be rooted in more social or environmental factors. Either way, it’s important to understand that mental illnesses are complex, multifaceted conditions; and just because you display one risk factor does not mean you will develop SAD. Conversely, you may have none of the risk factors mentioned below and still develop SAD.

What’s important is to always keep an eye on your mental health and speak with a licensed mental health care provider or your primary physician if you suspect you may be dealing with a mental illness.

Some commonly known risk factors associated with SAD include:

  • Being a young adult (12-24).
  • Being an older adult (over the age of 50).
  • Having an active addiction.
  • Having a family member who has had SAD.
  • Being a woman; women are affected more often than men.
  • Having another mental health condition such as major depressive disorder or bipolar disorder (especially bipolar II disorder)

Coping Strategies For SAD

SAD can be an extremely difficult condition to live with. Fortunately, there are many effective and healthy coping strategies for SAD recommended by mental health professionals. Even if the strategies don’t fully mitigate your symptoms, they can decrease the severity and make them more manageable.

Below are some simple coping strategies to help ease the symptoms of SAD:

  • Start your coping routine before your typical onset of symptoms
  • Do physical activity 3-4 times a week for at least 30 minutes
  • Eat healthy, well-balanced meals
  • Establish and stick to a regular daily routine
  • Limit alcohol consumption and abstain from mood-altering substances
  • Try to be with other people and confide in someone you trust
  • Do things that you enjoy like gardening or watching your favorite TV show
  • Try aromatherapy
  • Practice yoga or meditation
  • Attend support groups if needed

It’s important to remember that while coping strategies can be an effective way to manage symptoms of SAD, it’s always recommended to seek help from a professional mental health care provider.

Treatment For SAD

Treatment used for SAD can be used individually or in combination. Effective treatments include:

Light Therapy

Light therapy is one of the most common ways SAD is treated. During light therapy, patients sit in a special box, called a light box, that mimics natural outdoor sunlight. This is typically done on a daily basis within the first hour of waking.

Light therapy is so effective, in fact, that it is one of the first treatments given for fall or winter-onset SAD. While research on light therapy is limited, experts agree that it is a viable treatment option for those with SAD, with many patients reporting a decrease in negative symptoms within days or weeks.

Consider safely exposing yourself to sunlight to try and raise levels of serotonin in your body. Before trying light therapy with a light box or artificial light source, always talk with your health care provider first.

Vitamin D Supplements

Low levels of vitamin D, whether caused by low dietary intake or lack of sunlight, are common among people with SAD. However, data is limited on the effect vitamin D supplements can have on SAD, and it remains unclear if they can aid in symptom management. Nonetheless, vitamin D deficiency is a real condition that should be addressed. If you suspect that you have low vitamin D levels, talk with your doctor before beginning any new supplement regimen.

Antidepressant Medication

Selective serotonin reuptake inhibitors (SSRIs) are commonly used in the treatment of SAD. Additionally, some SSRI’s are effective in the management of SUDs, especially when combined with supportive talk therapy.

As with any medication, it’s important to talk with your doctor before pursuing any type of prescription, or before taking medications “off label,” or against their intended use.


There are many types of psychotherapy; however, cognitive behavioral therapy (CBT) is helpful in the treatment of SAD. CBT is frequently used in the treatment of SUDs and is an approach that many mental health professionals have found effective in their clients.

Whether you think you have SAD or you are 100% certain, it is recommended that you consult with a mental health professional. They will evaluate your symptoms and provide support as deemed necessary.

Don’t Wait To Get Help

It is a good time to seek professional help if the healthy coping strategies are not helping, you notice an increase in unhealthy coping, and your symptoms of SAD are persistent and interfering with daily life activities.

If you feel your depression is severe or if you are abusing drugs or alcohol, the time to get help is now. No one should have to live with mental illness or addiction alone. To get started on your recovery today, contact a treatment provider to learn what options are available to you.