What causes seasonal depression

Seasonal affective disorder (SAD) - Symptoms and causes


Seasonal affective disorder (SAD) is a type of depression that's related to changes in seasons — SAD begins and ends at about the same times every year. If you're like most people with SAD, your symptoms start in the fall and continue into the winter months, sapping your energy and making you feel moody. These symptoms often resolve during the spring and summer months. Less often, SAD causes depression in the spring or early summer and resolves during the fall or winter months.

Treatment for SAD may include light therapy (phototherapy), psychotherapy and medications.

Don't brush off that yearly feeling as simply a case of the "winter blues" or a seasonal funk that you have to tough out on your own. Take steps to keep your mood and motivation steady throughout the year.

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In most cases, seasonal affective disorder symptoms appear during late fall or early winter and go away during the sunnier days of spring and summer. Less commonly, people with the opposite pattern have symptoms that begin in spring or summer. In either case, symptoms may start out mild and become more severe as the season progresses.

Signs and symptoms of SAD may include:

  • Feeling listless, sad or down most of the day, nearly every day
  • Losing interest in activities you once enjoyed
  • Having low energy and feeling sluggish
  • Having problems with sleeping too much
  • Experiencing carbohydrate cravings, overeating and weight gain
  • Having difficulty concentrating
  • Feeling hopeless, worthless or guilty
  • Having thoughts of not wanting to live

Fall and winter SAD

Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:

  • Oversleeping
  • Appetite changes, especially a craving for foods high in carbohydrates
  • Weight gain
  • Tiredness or low energy

Spring and summer SAD

Symptoms specific to summer-onset seasonal affective disorder, sometimes called summer depression, may include:

  • Trouble sleeping (insomnia)
  • Poor appetite
  • Weight loss
  • Agitation or anxiety
  • Increased irritability

Seasonal changes and bipolar disorder

People who have bipolar disorder are at increased risk of seasonal affective disorder. In some people with bipolar disorder, episodes of mania may be linked to a specific season. For example, spring and summer can bring on symptoms of mania or a less intense form of mania (hypomania), anxiety, agitation and irritability. They may also experience depression during the fall and winter months.

When to see a doctor

It's normal to have some days when you feel down. But if you feel down for days at a time and you can't get motivated to do activities you normally enjoy, see your health care provider. This is especially important if your sleep patterns and appetite have changed, you turn to alcohol for comfort or relaxation, or you feel hopeless or think about suicide.

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The specific cause of seasonal affective disorder remains unknown. Some factors that may come into play include:

  • Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may cause winter-onset SAD. This decrease in sunlight may disrupt your body's internal clock and lead to feelings of depression.
  • Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in SAD. Reduced sunlight can cause a drop in serotonin that may trigger depression.
  • Melatonin levels. The change in season can disrupt the balance of the body's level of melatonin, which plays a role in sleep patterns and mood.

Risk factors

Seasonal affective disorder is diagnosed more often in women than in men. And SAD occurs more frequently in younger adults than in older adults.

Factors that may increase your risk of seasonal affective disorder include:

  • Family history. People with SAD may be more likely to have blood relatives with SAD or another form of depression.
  • Having major depression or bipolar disorder. Symptoms of depression may worsen seasonally if you have one of these conditions.
  • Living far from the equator. SAD appears to be more common among people who live far north or south of the equator. This may be due to decreased sunlight during the winter and longer days during the summer months.
  • Low level of vitamin D. Some vitamin D is produced in the skin when it's exposed to sunlight. Vitamin D can help to boost serotonin activity. Less sunlight and not getting enough vitamin D from foods and other sources may result in low levels of vitamin D in the body.


Take signs and symptoms of seasonal affective disorder seriously. As with other types of depression, SAD can get worse and lead to problems if it's not treated. These can include:

  • Social withdrawal
  • School or work problems
  • Substance abuse
  • Other mental health disorders such as anxiety or eating disorders
  • Suicidal thoughts or behavior


There's no known way to prevent the development of seasonal affective disorder. However, if you take steps early on to manage symptoms, you may be able to prevent them from getting worse over time. You may be able to head off serious changes in mood, appetite and energy levels, as you can predict the time of the year in which these symptoms may start. Treatment can help prevent complications, especially if SAD is diagnosed and treated before symptoms get bad.

Some people find it helpful to begin treatment before symptoms would normally start in the fall or winter, and then continue treatment past the time symptoms would normally go away. Other people need continuous treatment to prevent symptoms from returning.

By Mayo Clinic Staff


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Seasonal Affective Disorder | Johns Hopkins Medicine

What is seasonal affective disorder?

Seasonal affective disorder, or SAD, is type of depression. It happens during certain seasons of the year—most often fall or winter. It is thought that shorter days and less daylight may trigger a chemical change in the brain leading to symptoms of depression. Light therapy and antidepressants can help treat SAD.

What You Need to Know

  • Depression is different from feeling sad or unhappy. It is not a sign of personal weakness or a condition that can be willed or wished away.
  • Get help. If you think you may be depressed, see a healthcare provider as soon as possible.
  • Women are affected more often than men.
  • Without treatment, depression can last weeks, months or years, but most people respond well to medication, therapy or a combination of the two.
  • Most people with clinical depression who seek treatment see improvement, usually within weeks.

Who is at risk for SAD?

SAD usually starts during adulthood. The risk of SAD increases with age. It's rare in people under age 20. Women are affected more often than men.

What causes SAD?

Less sunlight and shorter days are thought to be linked to a chemical change in the brain and may be part of the cause of SAD.

Melatonin, a sleep-related hormone, also has been linked to SAD. The body naturally makes more melatonin when it's dark. So, when the days are shorter and darker, more melatonin is made.

What are the symptoms of SAD?

There are two types of SAD:

  1. Fall-onset.This is also called "winter depression." Symptoms of depression begin in the late fall to early winter months and ease during the summer months.

  2. Spring-onset.This is also called "summer depression." Symptoms of depression begin in late spring to early summer. This type is much less common.

The following are the most common symptoms of SAD:

  • Increased sleep and daytime drowsiness

  • Loss of interest and pleasure in activities formerly enjoyed

  • Social withdrawal and increased sensitivity to rejection

  • Irritability and anxiety

  • Feelings of guilt and hopelessness

  • Fatigue, or low energy level

  • Decreased sex drive

  • Decreased ability to focus or concentrate

  • Trouble thinking clearly

  • Increased appetite, especially for sweets and carbohydrates

  • Weight gain

  • Physical problems, such as headaches

Symptoms tend to come back and then improve at about the same times every year.

The symptoms of SAD may look like other mental health conditions. Always see a healthcare provider for a diagnosis.

How is SAD diagnosed?

Depression often happens with other conditions, such as heart disease or cancer. It may also happen with other disorders, such as substance use disorder or anxiety. For these reasons, early diagnosis and treatment is key to recovery.

A diagnosis of SAD may be made after a careful mental health exam and medical history done by a psychiatrist or other mental health professional.

How is SAD treated?

The treatments for "winter depression" and "summer depression" often differ, and may include any, or a combination, of the following:

  • Exposure to sunlight. Spending time outside or near a window can help relieve symptoms.

  • Light therapy. If increasing sunlight is not possible, exposure to a special light for a specific amount of time each day may help.

  • Psychotherapy. Cognitive-behavioral or interpersonal therapy helps change the distorted views you may have of yourself and the environment around you. It can help you improve interpersonal relationship skills, and identifying things that cause you stress as well as how to manage them.

  • Antidepressants. These prescription medicines can help correct the chemical imbalance that may lead to SAD.

There are also things you can do for yourself to help relieve symptoms:

  • Get help. If you think you may be depressed, see a healthcare provider as soon as possible.

  • Set realistic goals in light of the depression. Don't take on too much. Break large tasks into small ones, set priorities, and do what you can as you can.

  • Try to be with other people and confide in someone. It is usually better than being alone and secretive.

  • Do things that make you feel better. Going to a movie, gardening, or taking part in religious, social, or other activities may help. Doing something nice for someone else can also help you feel better.

  • Get regular exercise.

  • Expect your mood to get better slowly, not right away. Feeling better takes time.

  • Eat healthy, well-balanced meals.

  • Stay away from alcohol and drugs. These can make depression worse.

  • Delay big decisions until the depression has lifted. Before deciding to make a significant transition—change jobs, get married or divorced—discuss it with others who know you well and have a more objective view of your situation.

  • Remember: People rarely "snap out of" a depression. But they can feel a little better day-by-day.

  • Try to be patient and focus on the positives. This may help replace the negative thinking that is part of the depression. The negative thoughts will disappear as your depression responds to treatment.

  • Let your family and friends help you.

Key points about SAD

  • SAD is a type of depression that happens during a certain season of the year—most often fall and winter.

  • There is no clear cause of SAD. Less sunlight and shorter days are thought to be linked to a chemical change in the brain and may be part of the cause of seasonal affective disorder (SAD). Melatonin, a sleep-related hormone, also may be linked to SAD.

  • In general, nearly everyone with depression has ongoing feelings of sadness, and may feel helpless, hopeless, and irritable.

  • SAD may be diagnosed after a careful mental health exam and medical history done by a psychiatrist or other mental health professional.

  • Depression is most often treated with light therapy, therapy, and in some cases antidepressants.

What is seasonal depression? | Moscow

Article author: Nazarev Nikolay Vasilievich , narcologist, psychiatrist, sexologist, physiotherapist

What is seasonal depression?

Seasonal depression, or seasonal affective disorder, is a variant of recurring depression that begins in the fall/winter season. Women aged 18-30 are most susceptible to this condition, but it can occur at any age, even in a child.

How is seasonal depression different from clinical depression?

The difference follows from the name itself - this type of depression occurs in the autumn-winter period, while clinical depression does not depend on the season.

What are the causes of seasonal depression?

There are several of them. Reduced sunlight can lead to a decrease in serotonin, a brain chemical that is responsible for our good mood and emotional stability. Another hormone directly dependent on the amount of sunlight is melatonin. It is produced with the onset of darkness, causing our body to fall asleep. Since there is less light in winter, this hormone can increase in the body, and, as a result, there is a feeling of lethargy and drowsiness.

Why does seasonal depression occur in autumn and winter?

The combination of low levels of serotonin and high levels of melatonin cannot but affect the human biological clock. In people with seasonal depression, the change in circadian rhythms depending on the time of year is not consistent with the seasonal change in daylight hours, which creates difficulties in regulating the functioning of the body.

What are the signs of seasonal depression?

In general, the symptoms of seasonal depression are the same as those of any other depression. This is an oppressed, depressed state, low mood, regardless of external circumstances; decreased or loss of interest in activities that used to bring pleasure (anhedonia). You may also be concerned about fatigue, decreased performance, and decreased vitality.

Additional symptoms may be completely non-specific: feelings of guilt and worthlessness, anxiety, low self-esteem, difficulty concentrating; desire to be alone, irritability, eating disorders, drowsiness or insomnia.

What should I do to cope with seasonal depression? Recommendations.

There are no unambiguous universal recommendations, because each person is individual. Before visiting a doctor, you can try to walk more, exercise regularly, keep a daily routine, do not “treat” with alcohol and caffeine, eat foods rich in tryptophan (turkey, milk, egg whites, bananas, dried dates, peanuts, sesame, pine nuts ), because tryptophan promotes the formation of serotonin.

Does taking vitamin D and light therapy help?

Yes. Light therapy is an effective adjuvant treatment for depression. Adequate blood levels of vitamin D (40-80 ng/mL) are certainly important as well. In order to understand, you need to take a prophylactic or therapeutic dose of vitamin D - first you need to pass an analysis called the “level of 25-OH-vitamin D”, understand what level is at the moment and then choose an adequate dose.

What can make seasonal depression worse?

First of all, it is stress, bad habits, abuse of alcohol, caffeine. From the non-obvious - diet, unbalanced diet, physical inactivity.

How do you know when to see a doctor for seasonal depression?

At the slightest suspicion of seasonal depression, diagnosis and subsequent treatment should be carried out exclusively by a highly qualified specialist, a psychiatrist, since similar symptoms can appear with more dangerous mental illnesses and some somatic ailments.

Can seasonal depression be prevented?

You can try to prevent. If you adhere to the so-called healthy lifestyle: eat varied and regular meals, walk a lot in the fresh air, observe the daily routine. But all this is difficult to do in the conditions of life in a metropolis.

What should you do if you notice that your loved one/friend has seasonal depression?

First of all, you need to understand that depression is a disease, not a weakness of character, and that depression is treatable. The best thing you can do is to advise to go to a specialist. You can offer to go to counseling together if the person is afraid. Separately, I would like to remind parents that depression "all ages are submissive." Moreover, it is in childhood that depression usually manifests itself atypically, and therefore it is especially difficult to identify it. In children, depression is most often manifested by behavioral disorders. Therefore, you need to be attentive to changes in the well-being and behavior of your loved ones.

Appointment with a psychiatrist

For more details, consult a qualified specialist at the Semeynaya clinic.

To find out prices for a psychiatrist appointment or other questions, follow the link below:

Psychiatrist named signs of seasonal depression | Society news | Izvestia

In autumn and winter, due to the decrease in sunlight, many people may experience signs of seasonal affective disorder (SAD) - a feeling of sadness and loss of energy. On Friday, September 17, psychiatrist of the SberHealth medical online service Viktor Nurdaev told Izvestia about what other signs of this phenomenon exist, and how to deal with them.

According to the specialist, most often the symptoms of affective disorder are observed in the autumn and winter periods, much less often depressive symptoms can appear in the spring and early summer.

A likely cause of SAD may be circadian rhythm disturbance, that is, a malfunction of the body's "internal clock," according to which many biological processes operate; increased production of melatonin and decreased serotonin due to insufficient production of vitamin D.

Melatonin is a hormone that causes drowsiness in response to darkness. As the days get darker, the production of melatonin in the body increases accordingly. In response, people with seasonal depression experience drowsiness and lethargy. Also, with less skin exposure to sunlight during the fall and winter, people with seasonal depression may produce less vitamin D. Since vitamin D is thought to play a role in the activity of the happy hormone serotonin, deficiency leads to clinically significant depressive symptoms.

“People with seasonal affective disorder may experience a sad mood and a lack of energy. Tearfulness, irritability, fatigue increase, efficiency decreases. Often there is apathy, difficulty concentrating, lengthening night sleep. The consumption of sweet and starchy foods may increase, which leads to a set of excess body weight, ”Nurdaev said.

Conversely, in a less common summer seasonal disorder, symptoms are associated with poor appetite, weight loss, insomnia, agitation, restlessness, anxiety, and even violent episodes.

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