Seasonal Depression: Why Winter Makes Us Sad and How to Overcome it

Have you ever been depressed because of the darker days in winter or have you ever felt low on energy when there are longer nights in winter? Well, you are not alone as this is seasonal affective disorder (SAD), also known as seasonal depression, which is experienced by many people during the late winters or early fall.

Depression is a mood disorder that causes a continuous feeling of sadness and loss of interest. People who suffer from a milder form of depression, this mood disorder can affect many aspects of their life negatively. It can complicate any severe health conditions if they have any, such as diabetes, heart disease, or cancer.

Having any form of depression can also lead to difficulties with pain, sexual desire, performance, and sleep.

There are many types of depression, such as Major Depressive Disorder, Persistent Depressive Disorder, and Seasonal Affective Disorder. This article will focus on explaining what Seasonal Affective Disorder (SAD) is, who is likely to get SAD, what the symptoms are, and what treatment options are available.


What is Seasonal Affective Disorder (SAD)?

Seasonal Affective Disorder is a type of a depressive disorder that occurs at a particular time each year, in most common cases it is during winter (1). It is also known as seasonal depression, and it can affect your mood, sleep, eating habits, energy levels, relationships, social life and overall self-worth (2). It may lead you to feel like a different person in the summer and then a completely different person during the winters.

For example, you may feel more hopeless, sad, tensed and stressed during winters compared to summer or spring. Seasonal depression usually begins in fall or winter as days start to get shorter and darker. However, it can also happen during the summer months as some people get depressed with the longer days.

According to the Royal College of Psychiatrists (3), seasonal depression affects around 1% to 2% of the population, with women and young people more affected. However, a recent survey showed that SAD prevalence ranges from 9.7 percent in New Hampshire to 1.4 percent in Florida (4).

Seasonal depression is also more common in people who live at least 30 degrees latitude north or south such as Austin, Florida, Texas, Egypt, Hangzhou, China, U.K, or Australia. However, research also shows that no matter where you live, or how dark or cold the winters are, seasonal depression is highly manageable and treatable (4).

Seasonal depression can be diagnosed in children and adolescents (5). This is especially the case for those who suffer from bulimia nervosa, anxiety disorders, and other mood disorders.

Seasonal depression facts
7 facts about seasonal depression [Image via Upper Eden Medical Practice]

Causes of Seasonal Depression

There is no exact cause of Seasonal affective disorder (SAD), however, there are some relevant theories which explain the grounds of seasonal depression. Many theories feature the disorder to the decrease of daylight hours in winters. These shorter days and less exposure to sunlight affect the body by disrupting the following features:

  • Circadian rhythms: These are your body’s internal sleep-wake cycle which responds to changes between darkness and brightness to regulate your mood, sleep, and appetite. Hence, longer nights and shorter days during winters interrupt your internal body’s clock leading you to feel groggy, disoriented, and sleepy during winter days.
Circadian rhythms
Image via Lux Review
  • Production of melatonin: During night time, your brain produces a hormone called melatonin to help you have a healthy sleep. When sunlight appears in the morning, the brain stops producing this melatonin, so you feel awake and alert. Due to long nights of winter, your mind ends up producing melatonin for a more extended period, leaving you feeling tired and lazy the whole day with little sunlight.
  • Production of serotonin: Less sunlight during the winter season can decrease the level of serotonin produced in our brain. The functioning of this neurotransmitter, serotonin, is to regulate mood. A deficit in serotonin can lead to depression, reduced sleep, memory problems and reduced sexual desire in the long-run.

Signs and Symptoms for Seasonal Depression

Seasonal affective disorder (SAD) is diagnosed by licensed clinical Psychologists and Psychiatrists using the Diagnostic and Statistical Manual (DSM-5). This is a handbook of psychological and mental disorders, which contains descriptions, symptoms, and other criteria for diagnosis (6). According to the DSM-5, seasonal depression is differentiated from depression by the reduction in symptoms during summer and spring months. Common symptoms of seasonal depression include the following:

  • Depressed mood
  • Low self-esteem
  • Loss of interest and pleasure in activities you previously enjoyed
  • Hunger and weight fluctuations
  • Feeling angry, irritable, stressed, or anxious
  • Unsolved aches and pains
  • Changes in sleeping pattern
  • Difficulty concentrating
  • Fatigue and lack of energy; reduced sex drive
  • Use of drugs or alcohol for comfort
  • Feelings of sadness, hopelessness, and despair

Similar to depression, the severity of seasonal depression can be different for each person. This depends on the genetic vulnerability and most importantly, the geographic location. Usually, the symptoms start off as mild and begin to worsen through the darkest days of winter. Then again, by summer or early summer, these symptoms start to alleviate.

Diagnosis and Evaluation of Seasonal Depression

Even with extension evaluation and thorough examination, a correct diagnosis of seasonal depression can be difficult because other types of depression have similar symptoms. Hence, the following are required for a correct diagnosis of SAD (7):

  • Physical exam: your general practitioner or physician may do an extensive physical exam and ask in-depth questions about your health. In some cases, depression can be associated with underlying health conditions, such as thyroid issues.
  • Lab tests: For this, your physician will check your complete blood count in order to see you are healthy or not
  • Psychological evaluation: This will be a complete assessment of your mental health and emotions in order to check for your depression symptoms. You will be asked about your symptoms, thoughts, feelings, and behavior patterns.  You may also fill a questionnaire and answer relevant questions during the intake interview process.
  • DSM-5: Your mental health professional will do a criteria check for seasonal depressive episode registered in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), issued by the American Psychiatric Association.

Moreover, to be clinically diagnosed with seasonal depression, you need to have symptoms for two or more continuous years. SAD may start at any age, but it naturally begins when a person is between ages 18 and 30 years old. No matter what the timing of your depression is, if you feel like it is getting out of control, you should seek help.

Seasonal Depression Treatment

There are three types of treatments for people with seasonal depression: light therapy, psychotherapy, such as CBT and medication. The goal of all these three treatments is to assist people with SAD to improve their quality of life psychologically and physically. They also focus on improving their relationships, school, work and social engagement that previously seemed frozen by their excessive sadness during winter months. We will not look at each treatment in detail:

  1. Light therapy: This form of treatment is also known as phototherapy. Light therapy aims to replace the missing daylight of winter artificially by exposing you to bright light some period. This leads to a reduction in the secretion of melatonin, so you feel more awake throughout the day. Research has shown that this form of therapy is effective 85 percent of the time in SAD cases. However, the length and timing of light exposure are different for each individual with varying amount of symptoms. Hence, your mental health professional will help identify the right amount of light therapy that you need. There is one caveat in this type of treatment, it has to be done daily during winter months rather than a weekly or bi-weekly basis. Sometimes starting light therapy before the onset of symptoms in the fall season may prevent the seasonal affective disorder from occurring during winters (8).
  • Psychotherapy: According to American Psychological Association (9), Cognitive Behavioral Therapy (CBT) is recommended for the treatment of GAD. The basic idea essential to CBT is that changing negative thoughts and feelings can alleviate problem associated with seasonal depression. Methods used in cognitive therapy focus on changing the negative thinking patterns and beliefs which revolve around the worrying process; this approach is called cognitive restructuring. In many cases, CBT can be as effective as light therapy in treating seasonal depression but without any risky side effects.
  • Medication: If light therapy doesn’t work for you, your doctor may suggest antidepressant medication. These medications include SSRI antidepressants, as they reduce the serotonin levels in the brain. FDA in the US has suggested the drug bupropion (Wellbutrin) to treat seasonal affective disorder (10). However, antidepressants come with a lot of side effects therefore it is important to weigh the benefits and risks before starting any medication for long-term.


1. Roecklein, K. A., & Rohan, K. J. (2005). Seasonal affective disorder: an overview and update. Psychiatry (Edgmont (Pa. : Township)), 2(1), 20–26.

2. Meesters, Y., & Gordijn, M. C. (2016). Seasonal affective disorder, winter type: current insights and treatment options. Psychology research and behavior management, 9, 317–327.


4. Rosen, L. N., Targum, S. D., Terman, M., Bryant, M. J., Hoffman, H., Kasper, S. F., Hamovit, J. R., Docherty, J. P., Welch, B., & Rosenthal, N. E. (1990). Prevalence of seasonal affective disorder at four latitudes. Psychiatry research, 31(2), 131–144.

5. Swedo, S. E., Pleeter, J. D., Richter, D. M., Hoffman, C. L., Allen, A. J., Hamburger, S. D., Turner, E. H., Yamada, E. M., & Rosenthal, N. E. (1995). Rates of seasonal affective disorder in children and adolescents. The American journal of psychiatry, 152(7), 1016–1019.

6. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC:  Author.

7. Melrose S. (2015). Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches. Depression research and treatment, 2015, 178564.

8. Campbell, P. D., Miller, A. M., & Woesner, M. E. (2017). Bright Light Therapy: Seasonal Affective Disorder and Beyond. The Einstein journal of biology and medicine : EJBM, 32, E13–E25.

9. Rohan, K. J., Lindsey, K. T., Roecklein, K. A., & Lacy, T. J. (2004). Cognitive-behavioral therapy, light therapy, and their combination in treating seasonal affective disorder. Journal of affective disorders, 80(2-3), 273–283.


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