what is winter depression or seasonal affective disorder SAD

What Is Winter Depression, Winter Blues or Seasonal Affective Disorder (SAD)

Written by Valentina Dragomir, Psychotherapist | Fact Checked | See our editorial process

Winter holidays are coming soon and many of us are looking forward to them and the gifts. But for some of us the winter season means a low mood, sometimes even debilitating. With the season transition from autumn to winter some of us may start to feel sad, maybe we crave sweets more often, or have low energy.

These can be symptoms of seasonal depression. We will see in more detail what is winter depression, also called winter blues or seasonal affective disorder (SAD). We will see below what the symptoms of winter depression are and what we can do to overcome it.

What is winter depression or seasonal affective disorder?

Winter depression is a subtype of major depression disorder (MDD). In the Diagnostic and Statistical Manual of Mental Disorders, the fifth edition (DSM-5), the seasonal affective disorder is identified as the major depressive disorder with seasonal pattern. This means that this subtype of major depression occurs repeatedly in certain seasons, generally in autumn or winter.

Seasonal depression or winter depression occurs usually in autumn or winter with remission in spring. Depression in summer exists as well, although it is rare, it appears in spring or summer with remission in fall.

There is an easier form of winter depression, in which the symptoms are not so severe, the affected person being able to function close to the usual level. This is not major depression, but rather similar to melancholia (winter blues).

What are the symptoms of seasonal depression?

According to the DSM-5 criteria for major depressive disorder with seasonal pattern, the symptoms should be present only in one season, with remission in a different season (eg winter or summer), with occurrence in the last two years. Seasonal depression or winter depression has several specific symptoms. The symptoms of winter depression are exactly the same for major depression, with several specific features such as:

  • Craving carbohydrates (or something sweet, donuts, chips, bread, pasta, chocolate, ice cream and other sweet foods)
  • Lack of energy
  • Prolonged sleep
  • Eating excessively and gaining weight

The symptoms of major depression are as follows (DSM-5):

  • Depressive mood most of the day, almost every day.
  • Diminished interest and pleasure in all or almost all activities, most of the day, almost every day.
  • Significant weight loss or weight gain without a particular diet, or increase / decrease in appetite almost daily.
  • Insomnia or hypersomnia almost every day.
  • Psycho-motor agitation or slowness almost every day, observable by others.
  • Fatigue or lack of energy almost every day.
  • Feeling of worthlessness or excessive guilt (which can be delusional) almost every day.
  • Decreased ability to concentrate and think, indecisiveness, almost every day.
  • Recurrent thoughts of death (not just fear of death), recurrent suicidal thoughts without a specific plan, or suicide attempt, or a plan to commit suicide.

If you are in crisis and you have suicidal thoughts, contact the relevant authority in your country.

In Romania this authority is

Info icon
The Romanian Suicide Prevention Alliance. / Phone 0800-801-200 / https://www.antisuicid.com/

Diagnostic criteria for major depressive disorder with seasonal pattern

  • There is a regular temporal relationship between the onset of major depression symptoms and a specific time of year (e.g. autumn or winter). Seasonal psycho-social stressors that can have a direct influence (e.g. being unemployed in regular winter) are excluded.
  • Complete remissions (or a change from major depression to mania or hypo-mania) that also occur at a specific time of year (for example, depression disappears in spring).
  • In the last two years, two episodes of major depression were present, demonstrating the relationship between depression and a specific period of the year, without the occurrence of other episodes of non-seasonal major depression in the same period of time.
  • Seasonal pattern of depression episodes are substantially more numerous than other depression episodes that occurred during the individual’s lifetime.

Take the winter depression test (SPAQ) online

What are the causes for winter depression or seasonal affective disorder?

Seasonal depression appears in some people who have a certain sensitivity to natural light or lack of light. There are several factors that lead to the onset of winter depression. In addition to light sensitivity, the genetic component and the chemistry of the brain also play a role in the occurrence of major depression with a seasonal pattern.

It seems that the main cause for winter depression is how the body responds to light. That is why many people who have tried light therapy have reported that their seasonal depression has improved. For summer depression which is rare in those with seasonal depression, the causes are different and we will explore them in another article.

Poor exposure to natural sunlight

Sunlight is very beneficial for people. It helps us produce an important vitamin, vitamin D, which regulates our circadian rhythm, internal clock, and helps balance certain chemicals in the brain.

Serotonin and melatonin, two light-responsive chemicals play an important role in seasonal depression and we will talk about them below.

As for vitamin D, it is only produced when our body receives natural light directly on the skin. A low level of vitamin D or vitamin D deficiency is associated with the presence of symptoms for depression.

Increased production of melatonin

People with seasonal depression may have an excess production of melatonin. This happens during the time when the length of the day decreases and the duration of the night increases. For example, this can happen in winter.

Melatonin is a hormone that is produced in the brain by the pineal gland when it is getting dark or after the sun sets.

Melatonin is responsible for regulating sleep. That’s why at night our brain secretes melatonin and we get sleepy. But in winter depression, the presence of excess melatonin can cause drowsiness, lethargy or fatigue during the day.

Difficulty adjusting the amount of serotonin in the brain

Serotonin is a neurotransmitter responsible for regulating mood. It is widely accepted that low serotonin levels play a role in the existence of depression.

Neurotransmitters are substances located between the neurons in the synaptic cleft. They make it possible to transmit signals from one neuron to another (and to other cells or muscles) through synapses.

But because we are extraordinarily complex beings, and things are not always simple, neurotransmitters need other substances that assist them on their way from one neuron to another. These substances or carriers are more numerous in people who have seasonal depression, and they transport serotonin faster between the neurons. Therefore, the level of serotonin is lower between neurons.

There is a study that shows that in people who have winter depression, this substance (it is a type of protein) that carries serotonin fluctuates depending on the natural light. Thus, in summer, due to the stronger sunlight and longer daylight the level of substance that transports serotonin is generally low, and it increases in the cold season. That is why people who have winter depression have remission in the spring.

Why do we suffer from winter depression?

In addition to the causes outlined above, there is an important explanation in my point of view regarding the existence of this disorder in humans. Evolutionism points to our ancestors who, in the cold season, retreated to safe places for energy conservation, and for survival of the cold season. They also took care of their newborns conceived in the spring / summer, in remission of depression.

This is basically what we do in winter. With the coming of the cold season, we stay inside more, spend more time alone, eat more and gain weight, want to sleep more, feel more tired and lacking energy. These symptoms that can be present in most people (winter blues) and can be more severe in those with winter depression.

How is seasonal depression treated?

For the treatment of seasonal depression it is proceeded exactly as for depression: psychotherapy, medication if needed, changes in lifestyle. In addition to these interventions, phototherapy is also an option, a special technique for treating seasonal depression. However, these interventions don’t exclude one another. They work hand in hand for your well being.

Psychotherapy for winter depression

Psychotherapy helps people with depression in general, and seasonal affective disorder.

Psychotherapy can help you:

  • Discover and understand how certain problems or events have led to depression and how or what a person can do to manage these events or situations
  • Understanding how certain behaviors, thoughts, or other personal factors contribute to the depressive state and how or what the sufferer can do to change these aspects and improve their emotional state
  • Learning techniques, skills, coping strategies or learning how to manage emotions, thoughts, situations, relationships or events or other factors that have a negative impact on the person’s life
  • Gaining control and pleasure in life

What medication is available to treat seasonal affective disorder?

Depending on the severity of depression and the impact of this disorder in one’s life, drug treatment may also be prescribed. It is important to understand that medicines help people who need them. Thanks to the scientific advancement in science, medicine and technology we can get the help we need and heal many diseases and disorders, including depression.

One of the most common drugs prescribed for treatment of winter depression is the selective serotonin reuptake inhibitors. If we go back a little to the causes that lead to seasonal depression, it is the fast reuptake of serotonin in the brain leading to a deficiency of this neurotransmitter. Selective serotonin inhibitors are responsible for maintaining a balanced level of serotonin in the brain, resulting in the improvement of the affective state.

Of course, the psychiatrist is the specialist who decides what kind of antidepressant is best for his patient.

Many studies show that a combination of medication and psychotherapy gives the most favorable outcomes in the treatment of depression.

Phototherapy or light therapy for treating winter depression

Phototherapy or light therapy is an effective method for treating winter depression. It is, in some countries, the first treatment option for this type of depression.

Why would light therapy be effective? Because it seems to simulate the exposure to sunlight and bring its benefits: balancing serotonin, melatonin, circadian rhythm, which can lead to improved emotional state.

Light therapy lamps for treating winter depression are different from the lamps designed to treat dermatological diseases such as psoriasis or eczema. That is why we need to look for those special products designed to treat winter depression.

What lifestyle changes do you make to deal with seasonal depression?

Our lifestyle includes several aspects that we look at when we want to overcome winter depression. For example, our relationships or social circles, sport, diet, leisure or free time, work-personal life balance, and so on. Some of these areas may determine the onset or maintain the symptoms of depression. In order to achieve the best results, sometimes people need to make changes in some of the areas of their life.

It is important to resist the temptation to isolate or to be by ourselves. We need connections, social relationships and interactions to keep us healthy.

Sport also plays an important role in our mental and emotional balance. Regular physical activity is recommended for anyone, whether they have depression or not. But in depression it can help improve the emotional state.

Free time can also be used to do things we like such as activities that help us feel better (for example, psychotherapy). Of course, it is important to procrastinate as little as possible and do the things we normally do. Thus we maintain our sense of competence and our self-esteem does not suffer.

How diet can help with winter depression?

When I say diet, I am not referring to a particular diet, but to what we eat on a normal day. We can support our body during the winter period by consuming foods that contain tryptophan, the basic substance from which serotonin is made. Allowing our body to have enough resources to produce serotonin by itself is a good plus in winter. However, we should not exaggerate.

It is important that in general we have a varied and balanced diet in which we have vegetables, fruits, proteins, carbohydrates and fats. And in general we avoid excessive carbohydrate consumption which could lead to gaining weight.


As a summary of this informative article we have the most important points:

  • Winter depression (formerly known as seasonal affective disorder) is a subtype of major depression, identified in the DSM-5 as major depressive disorder with seasonal pattern.
  • Winter depression occurs in the cold season and it remits in spring.
  • Winter depression is a treatable disorder caused in some people by the lack of exposure to sunlight, increased production of melatonin and the difficulty of the body to regulate the amount of serotonin in the brain.
  • The treatment for winter depression includes psychotherapy, medication if needed, changes in one’s lifestyle. Phototherapy is also known to have important benefits for people who use it to treat winter blues.


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