The idea that people commonly experience sadness during the colder months isn't a new theory.

Alexandra Clay

The idea that people commonly experience sadness during the colder months isn’t a new theory.

As the days get shorter, many are experiencing the onset of winter depression, more clinically known as Seasonal Affective Disorder.

What is Seasonal Affective Disorder? 

Seasonal Affective Disorder (SAD) is defined by the NHS as “a type of depression that comes and goes in a seasonal pattern”. 

Typically people experience SAD in the winter, leading to the nickname “winter depression.” However, some can have reverse symptoms and experience the condition in the summer. 

The cause of SAD is typically linked to reduced sun exposure during fall and winter. A prominent theory is that a decrease in sunlight causes the hypothalamus to work improperly. This leads to an increase of melatonin, a decrease in serotonin, and a disruption of one’s circadian rhythm. Melatonin causes the feeling of sleepiness, and serotonin is linked to mood, appetite, and sleep. Moreover, SAD is rarely found in countries within 30 degrees of the equator where sunlight is readily available year-round, bolstering the theory that it is linked to sunlight. 

In the United States, SAD is now classified as Major Depressive Disorder with Seasonal Pattern by the DSM-5. The National Institutes of Health estimates that over 36 million Americans suffer from SAD in the fall. 

Symptoms of Seasonal Affective Disorder 

The symptoms of SAD are nearly the same as standard depression, though occur repetitively at around the same time every year. A few of the symptoms include persistent poor mood, tearfulness, feeling stressed or anxious, irritability, feelings of despair and worthlessness. The NHS’s list of symptoms also highlights a decrease in activity and lethargy. 

Diagnosis of SAD is often difficult as there are many types of depression with similar symptoms. The doctor carrying out the diagnosis will ask about several things, including general mood, lifestyle, and any possible changes related to the season. It is also possible that this will be followed by a physical exam. 

Treatments for Seasonal Affective Disorder 

One of the most common treatments is light therapy, which involves 20 to 60 minutes of exposure to a light specially designed to treat SAD. A large number of these lights are easily available on Amazon

A study of light therapy found that “53.3 per cent of individuals with SAD met criteria for full remission with light therapy”. Alternatively, actively seeking out sunlight can have a similar effect of boosting serotonin levels and reducing melatonin. 

However, the National Institute for Health and Care Excellence (NICE) recommends that SAD be treated in the same way as other types of depression. NICE has expressed concerns about the effectiveness of light therapy, and most health organizations recommend getting as much natural sunlight as possible rather than attempting to artificially supplement it. 

Counselling, either in the form of Cognitive Behavioral Therapy (CBT) or psychodynamic psychotherapy is frequently recommended. CBT focuses on identifying ways of altering one’s thinking to change “unhelpful thoughts and behaviours”, the aim of which is to apply skills learnt during treatment to everyday life. Psychodynamic psychotherapy aims to find if past experiences are affecting one’s current feelings. 

Antidepressants are often prescribed for depression and severe cases of SAD. Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed medication for SAD, as they increase the distribution of serotonin in the brain.

Alexandra Clay
BSc Computer Science

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