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Seasonal Affective Disorder (SAD)

Seasonal-Affective-Disorder-(SAD)

SAD, also known as seasonal affective disorder, is a type of mood disorder related to seasonal changes. It is also commonly known as seasonal depression and major depressive disorder (MDD) with seasonal patterns.

What Is Seasonal Affective Disorder (SAD)?

SAD refers to a seasonal affective disorder that a person may experience every year at the same time. It is considered a rare form of mood disorder and is also termed as summer or winter depression. The mood changes and other symptoms are quite similar to depression. A 2017 study 1 defined it as a subtype of bipolar disorder and major depressive disorder. People with this psychological condition experience certain symptoms from winter till late spring or early summer. When the season changes and the daylight hours get shorter during the fall and winter, people with this disorder may start to feel emotionally down.

Studies 2 have shown that this psychological condition often leads to major depression and becomes more apparent and severe during the winter season. It gradually decreases one’s energy and makes them extremely moody. Research 3 also claims that seasonal depression can be commonly observed among people who live further away from the equator. It affects various significant aspects of an individual’s life, such as:

  • Mood
  • Hormonal changes 4
  • Sleep pattern 5
  • Biological clock 6
  • Appetite 7
  • Energy level
  • Personal and professional relationships 8, 5(5), 31–33. ))
  • Sense of self-worth 9
  • Self-confidence
  • Daily activities 10

A 2005 research paper 11, 2(1), 20–26. )) describes this disorder as a prevalent mental health problem in which people experience major depression symptoms during winter and remission in summer. “SAD has focused on neurotransmitters, hormones, circadian rhythm dysregulation, genetic polymorphisms, and psychological factors.”, the study further added.

How SAD Affects Us?

The decreased amount of daylight may cause certain chemical changes in the brain, followed by mild to severe symptoms of depression. People with SAD start to feel better with the increasing daylight hours in the spring. Though the symptoms eventually resolve within a few months, this condition can have serious consequences on a person’s physical and psychological well-being. Being emotionally overwhelmed most of the time may affect people’s interpersonal commitments and relationships. It also affects how a person feels, thinks, and behaves with others. A 1993 research 12 explains that having a family member with a psychological disorder may increase the risk of being diagnosed with seasonal depression. Though often compared, seasonal mood disorder is more severe than winter blues, a less severe form of seasonal depression. Winter blues 8, 5(5), 31–33. )) refers to a feeling of depression associated with experiencing the cold and darkness of winter.

Research 13 says that seasonal depression affects around 10% of the global population. The prevalence is completely related to the latitude since the shorter daylight is involved. According to a 2015 study 14 , women are four times more likely than men to experience this psychological disorder.

Understanding SAD

Sunlight 15 plays a pivotal role in developing various psychological symptoms of seasonal affective disorder. Certain hormonal and chemical changes in the body are responsible for making SAD patients extremely moody and depressive. A 1986 study 16 suggests that people with this mood disorder often experience an overproduction of the melatonin hormone. Melatonin 17 refers to a hormone released by the pineal gland and is associated with responding to darkness and causing sleepiness. During winter, the days become shorter and it increases melatonin production in the human body. According to 2006 research paper 18 , people with seasonal depression feel extremely sleepy and lethargic due to melatonin over-production. Melatonin also has an important impact on several other symptoms of seasonal affective disorder.

A 2013 research paper 19 claims that people with seasonal depression experience difficulty in regulating serotonin, which is a neurotransmitter believed to be responsible for balancing mood. Decreased daylight is associated with vitamin D deficiency that often results in decreased serotonin production 20. Studies 21 have found that this condition disrupts people’s circadian rhythm and sleep patterns. Research 22 says that dopamine plays a critical role in light or dark adaptation and has a mutually inhibitory relationship with melatonin. Increased melatonin often causes lesser dopamine production 23 in the body. As dopamine develops a sense of pleasure and happiness 24 in people, decreased dopamine level makes people depressed and emotionally unwell.

SAD At A Glance

  1. Seasonal affective disorder (SAD) is a type of mood disorder associated with seasonal changes.
  2. People with SAD often experience certain mild to severe symptoms, such as daytime fatigue, sadness, self-harming thoughts, social withdrawal, and many more.
  3. Latitude differences, melatonin overproduction, reduced serotonin level, vitamin D deficiency are some of the significant contributing factors of seasonal depression.
  4. SAD can be diagnosed with the help of various physical examinations, laboratory tests, and psychological evaluations.
  5. Doctors often prescribe bright light therapy, cognitive-behavioral therapy, and antidepressant medication for SAD.

Symptoms Of SAD

Symptoms Of SAD
Seasonal Affective Disorder (SAD)


Seasonal affective disorder is not a separate disorder itself, rather a type of depression characterized by different seasonal symptoms. The signs and symptoms may vary from mild to severe depending upon the seasonal changes. Seasonal depression occurs with a return of symptoms every year when the amount of daylight starts to decrease. A 1999 study 25 suggests that people can start to experience the symptoms from October/November till February/March. When the symptoms become more apparent during fall or winter, it is termed as “Winter Depression”. Though the summer type is less common, a few people may experience the symptoms during the summer days also.

Generally, there are two types of symptoms according to different seasons, such as:

1. Winter symptoms

Most people experience severe symptoms during fall/winter, such as:

  • Appetite changes and weight gain 26
  • Tiredness or lethargy 27
  • Overeating due to carbohydrate craving 28
  • Daytime fatigue
  • Difficulty in thinking and concentrating
  • Desire to be alone
  • Feeling sad, cranky, and irritated
  • Self-harming thoughts 29
  • Social withdrawal 30
  • Reduced sexual interest 31
  • Feeling worthless and guilty 32
  • Aches and pains without proper reason 33
  • Use of drugs and alcohol for comfort 34
  • Desire for extreme physical activity 35
  • Feeling angry, anxious, and stressed 36
  • Changes in sleeping pattern 37
  • Consistent low mood
  • Crying without any reasonable trigger
  • Interpersonal difficulties 38

2. Summer symptoms

The mild summer symptoms include:

  • Insomnia, hypersomnia, or trouble sleeping 39
  • Poor appetite 40
  • Anxiety and agitation 41
  • Weight loss 42
  • Violent behavior 43
  • Feeling depressed most of the day

A 2008 study 8, 5(5), 31–33. )) claims that the symptoms of seasonal affective disorder can last for 4 to 5 months in a year. One can experience these symptoms at any age, but typically the symptoms start between the age of 18 to 30. Over time, the symptoms may become severe and affect one’s day-to-day activities. Except for seasonal patterns, the symptoms may depend on genetic vulnerability 44 and geographic location 45 .

Causes Of SAD

Causes Of SAD
Seasonal Affective Disorder (SAD)


A 2009 research paper 46 suggests that seasonal depression is often believed to be associated with reduced exposure to sunlight. An important theory 47 claims that reduced daylight may disrupt the functioning of a significant part of the brain named the hypothalamus. This condition affects several factors of the human body and ultimately leads to seasonal mood disorder. Though the exact causes of the seasonal affective disorder are still unknown, there are some significant factors that can trigger the symptoms, such as:

1. Circadian rhythm

During the winter season, most people experience decreased sunlight exposure. Sunlight is extremely essential for several important functions in our body. According to a 2006 study 48, decreased sunlight affects the biological clock or the circadian rhythm 49 of the human body that regulates our sleep-wake-cycle, hormones, appetite, and mood. This condition eventually leads to feelings of depression and makes one feel groggy, cranky, anxious, sleepy, and disorientated.

2. Latitude

Research 50 says that people who live in such places that have long winter nights and less sunlight because of the higher altitude are more likely to experience seasonal depression symptoms. Seasonal mood disorders are more common among the citizens of Canada and Alaska than the citizens of Florida. Winter is the longest season in Alaska and Canada. The amount of daylight is variable above the Arctic Circle. In Canada and Alaska, the sun disappears for months at a time. The reduced sunlight exposure and the frigid conditions increase the risk of seasonal mood disorder in Alaskans and Canadians. Similarly, the sunnier and temperate weather of Florida reduces the risk of being diagnosed with seasonal depression.

3. Overproduction of melatonin

Studies 51 have found that the human brain releases melatonin during the night and helps us to fall asleep. Decreased sunlight exposure causes overproduction of melatonin 52 hormone in our body. As melatonin regulates our sleep patterns and mood, increased melatonin levels may make us feel sleepy and lethargic at inconvenient times.

4. Decreased serotonin levels

Serotonin 53 is a neurotransmitter that affects people’s moods. Reduced sunlight causes a drop in serotonin production. A 2013 study 54 says that serotonin deficiency may lead to depression along with other symptoms, including appetite changes, memory problems, drowsiness, and low interest in sexual desire.

5. Vitamin D deficiency

Sunlight is a great source of vitamin D in the human body. A 2015 research paper 55 mentions that vitamin D and serotonin levels are interlinked with each other. During winter, our body experiences vitamin D deficiency followed by decreased serotonin levels and several depression symptoms.

Risk Factors Of SAD

Seasonal depression is more common among women than men. Similarly, younger adults tend to be diagnosed with this mood disorder more than older adults. This disorder can also be observed in those people who live far north or south of the equator as they experience less sunlight in the winter and longer daylight during the summertime. The following are some of the common factors that can increase the risk of seasonal depression:

  • Family history 12
  • Prior medical history 56 of bipolar disorder or major depressive disorder
  • Age 10
  • Gender 57

Complications Of SAD

One should take the signs and symptoms of seasonal depression very seriously as they become worse over time if not treated. These symptoms can cause several complications that include:

  • No interest in social interaction
  • School and work-life problems
  • Difficulties in performing daily activities
  • Suicidal thoughts
  • Anxiety and eating disorder

Read More About Eating Disorders Here

When To See A Doctor

When To See A Doctor
Seasonal Affective Disorder (SAD)


Feeling low or depressed for some days doesn’t mean that one has a seasonal affective disorder. It is completely normal to feel anxious and emotionally disturbed on some days. But one should visit and consult with a health care professional if they experience the following symptoms for more than two consecutive years:

  • Feeling down every day at the same time
  • Having no interest in social interaction
  • Facing difficulties in performing daily activities
  • Appetite and sleep pattern drastically changed
  • Turning to alcohol and other substances for comfort and relaxation
  • Feeling hopeless
  • Having repeated suicidal thoughts

Diagnosis Of SAD

Sometimes, it is extremely difficult to detect seasonal affective disorder even with proper evaluation as other types of mental health disorders may cause similar symptoms. A recent 2021 study 2 has claimed that one needs to experience the following symptoms for at least more than two consecutive years to be clinically diagnosed with this disorder:

  • Depression related symptoms that start and end according to seasonal changes
  • Not experiencing the symptoms during the seasons other than winter or summer
  • Feeling depressed and emotionally low most of the time of a year

Other than these, mental health care professionals may do a proper medical evaluation 58 of an individual in order to diagnose seasonal depression. The medical evaluation usually includes:

1. Physical examination

The health care professional may do a proper physical examination of the person and ask some important questions. The questionnaire is very essential for the diagnosis as seasonal depression can be underlying The questions may include:

  • The duration of the symptoms
  • The severity of the symptoms
  • Appetite and sleeping pattern changes
  • Difficulty in performing daily activities
  • Difficulty in thinking and concentrating
  • Family medical history
  • Any behavioral changes

2. Laboratory test

The doctor may do a blood test to know the complete blood count or test the thyroid to detect if there is an underlying health problem.

3. Psychological evaluation

The doctor may conduct a thorough psychological assessment of the person to better understand their signs and symptoms. The health care professional may ask the person about his/her:

  • Lifestyle
  • Mood
  • Eating habits and sleeping patterns
  • Seasonal behavior and thought process changes
  • Prior experience of any depressive disorder

4. DSM-5 criteria

DSM-5 59 refers to the diagnostic and statistical manual that is published by the American Psychiatric Association and used as a criterion to diagnose significant psychological disorders. DSM-5 does not consider SAD a separate psychological disorder, but a specifier of major depressive episode diagnosis. The doctor may use the DSM-5 criteria 60 to detect any seasonal depressive disorder listed in that specific manual.

Read More About DSM-5 Here

Treatment For SAD

Treatments for SAD vary depending upon the patient’s medical history and the severity of their symptoms. Mental health specialists often prescribe some traditional antidepressants to treat the symptoms of seasonal mood disorder. Besides medications, both summer and winter depression can be effectively treated with therapy and personal counseling. A 2003 research 61 has divided the treatments for seasonal depression into four main categories:

  • Bright light therapy 62
  • Psychotherapy 63
  • Medications
  • Vitamin D treatment

It is important to consult with a doctor about which treatment is best suited for you. The following are some of the most common beneficial treatments for Seasonal affective disorder.

1. Bright light therapy

One can administer bright light therapy which is also known as phototherapy. Research 64 explains that this therapy plays the role of natural outdoor light and works as an antidepressant by causing certain chemical changes in the brain. It is one of the most beneficial therapies that ensures the correct amount of light exposure. Light therapy can be done either with a lightbox or a dawn simulator.

a. Lightbox

Lightbox 65 delivers light that is ten times more intense than normal domestic light. One needs to sit 2 feet away from the lightbox for at least the first hour after waking up in the morning. A 2009 study 66 claims that the full-spectrum light of the lightbox indirectly shines into the eyes and reduces one’s depression and the other symptoms of mood disorder. One should not stare directly at the light for a longer time. This therapy may cause hypomania 67 in bipolar disorder patients.

b. Dawn simulator

A dawn simulator refers to a device that increases the amount of light in the bedroom. In the morning, this device simulates the rising sun and helps one to wake up. It gradually increases the light just as the sunlight does. Studies 68 have found that it can help to reset one’s circadian rhythm and improve mood.

However, a 2013 study 69 has found that light therapy can cause several side effects, such as agitation or irritability, headaches, eye strain, sleep disorders, blurred vision, and tiredness.

2. Psychotherapy

Psychotherapy 70 is another effective treatment option for the seasonal affective disorder as it may have long-lasting benefits. This treatment focuses on both the psychological and social aspects. One of the most common psychotherapies used to treat seasonal depression is cognitive-behavioral therapy (CBT) 71 or talk therapy. This specific therapy is based on the fact that the way we think and behave affects the way we feel. It helps the patients to deal with their negative thoughts, attitudes, and behavior regarding themselves and their environment. It also helps to manage the severe symptoms of seasonal mood disorder. A specially trained therapist may conduct two weekly group sessions for six weeks.

3. Medications

If the symptoms are severe and light therapy doesn’t work, the doctor may prescribe certain antidepressants to treat the winter depression. A 2019 research 34 has revealed that such antidepressants work on the serotonin level in the brain and reduce the severity of the SAD symptoms. Bupropion is the most commonly prescribed antidepressant medicine to treat seasonal depressive symptoms. It is believed to be the most effective one if taken at the start of the winter before the symptoms appear. However, it is extremely important to know the adverse side effects before starting antidepressant medication.

4. Mind-body connection

There are some extremely beneficial mind-body techniques that people often use to deal with SAD. The techniques include:

  • Yoga 72
  • Mindfulness practice 70
  • Meditation 73
  • Guided imagery 74
  • Music or art therapy 75

5. Vitamin D treatment

Research 76 claims that SAD is associated with vitamin D deficiency. Doctors often recommend seasonal depression patients to increase their vitamin D intake through their diet, exposure to sunlight, or vitamin supplements. However, studies examining the effectiveness of vitamin D treatment have led to inconclusive findings.

6. Healthy lifestyle

A recent 2020 research paper 7 suggests that a healthy lifestyle and habits are very beneficial to help reduce the severity of SAD symptoms. Certain lifestyle changes that one can include are:

  • Regular physical exercise
  • Proper sleep
  • Fresh fruits, vegetable, and protein diet
  • Drinking plenty of water

How To Cope With SAD

How To Cope With SAD
Seasonal Affective Disorder (SAD)


Besides treatment and medications, there are some effective ways through which one can manage depressive symptoms, such as:

  • Get as much natural sunlight as possible.
  • Follow your treatment and attend all therapy sessions.
  • Don’t hesitate to seek medical help if you find it difficult to cope with the depression yourself.
  • Follow a healthy lifestyle, get enough sleep, do regular physical exercise, eat balanced meals, and drink plenty of water.
  • Try to spend more time with your loved ones as it is always better than being alone.
  • Learn to practice meditation or other types of mindfulness techniques to manage your stress better.
  • If possible, plan a winter or summer vacation according to your seasonal depression pattern.
  • Do whatever makes you happy. Go to a movie, do gardening, listen to soothing music, take part in religious and social activities.
  • Don’t take any important decisions until the depression has lifted.
  • Try to be focused and think positive about the treatment result.

Overcome SAD

Seasonal affective disorder (SAD) is a type of seasonal depression that people experience from the winter till late spring or early summer. People with SAD often experience common depression symptoms according to seasonal changes. The symptoms vary from person to person and affect several aspects of an individual’s life, such as mood, appetite, energy, sleep, biological clock, and their interpersonal relationships. Several hormonal changes, circadian rhythm, and latitude differences are responsible for developing seasonal depression. Though it takes a lot of time, most people recover fully with proper treatment and medication. Along with treatment, healthy lifestyle choices can make it easier for people to deal with the severity of the symptoms.

Seasonal Affective Disorder (SAD) Reviewed By :


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