Seasonal Affective Disorder

Unlike traditional psychiatry, which rarely looks at the brain, Amen Clinics uses brain imaging technology to help identify underlying brain issues that may be associated with seasonal affective disorder.

What is Seasonal Affective Disorder?

Seasonal affective disorder (SAD) is a type of depression that is usually linked to changes in the seasons. For most people with this disorder, depressive symptoms begin in late autumn or early winter and subside during the spring and summer. Some people experience depression during the summer months, but this is much less common than winter depression. Short dark days and cold temperatures can make anyone wish for sunnier summer days, but seasonal affective disorder is more than just the winter blues. People with SAD say they sleep an extra 2.5 hours each night in the winter compared with the summer months. Those with the winter blues get an extra 1.7 hours of shuteye, and people who don’t have either of these conditions log a little over 40 extra minutes of sleep during the winter. The low moods and energy drain people experience can grow into a sense of emptiness or numbness that doesn’t dissipate. Eventually, it negatively impacts the way you think, how you feel, and how you act and can get in the way of daily living.

Who is Affected by SAD?

In the U.S., approximately 14% of adults experience the winter blues, but only an estimated 6% of Americans are affected by SAD. About 10% of people with SAD experience it during the summer months. However, experts suggest the number could be higher since the condition often goes unreported and undiagnosed. For example, people with SAD who have low levels of thyroid hormone may attribute their symptoms of lethargy and lack of motivation to hypothyroidism, so their seasonal affective disorder may go undetected. (See below for more information about who is at risk for SAD.)

What are the Symptoms?

People with SAD may experience many of the typical symptoms of depression, including persistant negative mood, lost of interest in pleasurable activities, feeling of worthlessness or sleeping too much or too little. Also, see below for longer list of symptoms.

What Causes SAD?

Although the scientific community has yet to identify the exact causes of SAD, it is believed that it may be related to neurotransmitter issues and neurohormone issues, as well as to lower levels of vitamin D due to reduced exposure to sunshine in winter months. With summer-onset SAD, longer days and rising temperatures and humidity levels may play a role. (See below for more information on the causes of SAD.)

Mental health conditions that are commonly seen with SAD include:

  • Depression
  • Bipolar disorder
  • Substance use disorders
  • Eating disorders

Why Choose Amen Clinics for Treating Seasonal Affective Disorders?

It is not uncommon for SAD to co-occur with other mental health disorders, which can make it more challenging to diagnose. At Amen Clinics, we use brain SPECT imaging, a state-of-the-art brain mapping tool that can be very helpful in getting an accurate diagnosis for seasonal affective disorder. SPECT helps detect underlying brain dysfunction and co-occurring disorders as well as their subtype.

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Seasonal Affective Disorder Brains Work Differently

Brain imaging research has found that people with seasonal affective disorder have lower levels of the “happy” neurotransmitter serotonin in the winter months due to problems with the serotonin transporter SERT. In addition, this condition is considered to be a type of major depressive disorder, and our brain imaging work at Amen Clinics has found 7 types of anxiety and depression, which means that seasonal affective disorder is not a single or simple disorder. Traditional psychiatry typically takes a one-size-fits-all approach to diagnosis and treatment, but giving everybody with SAD the same treatment will never work.

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What Causes Seasonal Affective Disorder?

We are still uncovering what causes seasonal affective disorder, but research has shown that the following may be contributing factors:

  • Neurotransmitter Issues: Abnormal regulation of the neurotransmitter serotonin, a feel-good chemical, has been found in people who have SAD.
  • Producing Too Much Melatonin: People with SAD may produce too much melatonin, which increases sleepiness and saps energy.
  • Low Levels of Vitamin D: During the winter months, we get less sunlight, which lowers production of vitamin D, known as the “sunshine vitamin.” Low levels of Vitamin D have been implicated in depression and bipolar disorder, as well as many other physical and mental health conditions.


Who is at Risk for Seasonal Affective Disorder?

People who are at increased risk of developing SAD include:

  • Women: Seasonal affective disorder is diagnosed 4 times more often in women than in men.
  • Young adults: The typical age of onset ranges from 18 to 30 years old.
  • Having a close relative with SAD: Seasonal affective disorder tends to run in families, which suggests some people may have a genetic predisposition for the disorder.
  • People who live far from the equator: The farther you live from the equator, the more susceptible you are to SAD. For example, only 1% of people who reside in Florida experience SAD while 9% of those living in Alaska have it. About 6% of people living in Canada and 2% of those in the United Kingdom suffer from SAD.
  • Night shift workers: Due to limited exposure to sunlight, people (and especially women) who do shift work may be at increased risk of developing SAD.
  • People with depression or bipolar disorder: Research shows that 24% of people with bipolar disorder and nearly 10% of those with major depressive disorder experience a seasonality to their condition compared with only 2.5% of healthy people.


Symptoms of SAD

People with SAD may experience many of the typical symptoms of depression, including:

  • Persistent sad or negative mood
  • Loss of interest in usually pleasurable activities
  • Restlessness, irritability, or excessive crying
  • Feelings of guilt, worthlessness, helplessness, hopelessness, or pessimism
  • Sleeping too much or too little, or early-morning awakening
  • Appetite changes and/or weight loss or weight gain
  • Decreased energy, increased fatigue, or feeling “slowed down”
  • Thoughts of death or suicide, or suicide attempts
  • Difficulty concentrating, remembering, or making decisions
  • Persistent physical symptoms (such as headaches, digestive problems, or chronic pain)
  • Chronic low self-esteem
  • Persistent feeling of being dissatisfied or bored


People who experience SAD during the winter may experience the following symptoms:

  • Lack of energy
  • Overeating and weight gain
  • Carbohydrate cravings
  • Sleeping more than usual
  • Social withdrawal
  • Trouble concentrating


People who experience SAD during the summer may experience the following symptoms:

  • Restlessness
  • Loss of appetite and weight loss
  • Trouble sleeping
  • Anxiety or agitation


“With A Better Brain Comes A Better Life”

– Daniel G. Amen, M.D.


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