Seasonal Affective Disorder (SAD)

Updated: July 23, 2022

Seasonal Affective Disorder (SAD), also known as winter or seasonal depression usually occurs during the autumn and winter months. This is thought to happen because of the lack of natural sunlight which impacts those who experience SAD.

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What Is SAD?

Seasonal Affective Disorder, or SAD is a condition which triggers low mood and depression due to a variety of factors. Interestingly, even though SAD is normally associated to the autumn and winter months when daylight hours are shorter so there is less sunlight, it can also occur in the summer months – although this is far rarer. This is known as ‘summer depression’ or ‘reverse SAD’ and is thought to occur because of the change in seasons and disruption to the body’s circadian rhythms, which, amongst other things, regulate the sleep cycle.


It should be recognised that the symptoms and causes of SAD vary between people and so individuals can experience it in different ways – therefore treatment should also be unique to a person’s needs.

What Are The Symptoms?

Apathy & Anhedonia

SAD can mean individuals lose interest and enjoyment in the activities they once did.

Cognitive Problems

SAD and all that it does can impact cognitive functioning, so people might find it difficult to concentrate and make decisions.

Emotional Difficulties

Those with SAD can feel persistent feelings of anxiety, sadness, and hopelessness

Emotional Dysregulation

People with SAD can feel unable to manage their emotions. For example they may become agitated and irritable, or snap in annoyance or anger.

Impact To Appetite

Due to the feelings and other symptoms that SAD creates, those impacted can experience changes in appetite which can also affect weight. This is especially so due to the increase in cravings for carb dense foods.


Due to the challenges that SAD creates, individuals can withdraw from social situations because they’re not interested in socialising and feel it’s too difficult.

Low Energy

SAD can cause fatigue and a general lack of energy in those affected by it.

Physical Symptoms

Because mood impacts the production of essential hormones, and due to the other ways in which SAD impacts a person’s mental and emotional states, as well as behaviour, they can also develop physical health problems, including headaches or body aches.

Sleep Issues

Depression affects sleep in different ways.  Some people experience insomnia, and cannot fall asleep.  Others may be able to fall asleep but wake up at night.  Whereas some people may sleep more than usual.  Often the sleep experienced does not feel restful, even if you are oversleeping.

Suicidal Ideation

SAD can become severe enough that people experience thoughts of suicide and death.

What Causes SAD?

Although SAD is not fully understood, there are many factors thought to contribute to its development including:


Genetic Inheritance: SAD  has been observed to run in families, which suggests that genetics may play a role in its development.


The reduction in sunlight: During the autumn and winter months we have less exposure to sunlight which can disrupt the body’s ability to produce mood regulating hormones like melatonin and serotonin, impacting the circadian rhythm.

Neurotransmitter imbalance: Those impacted with SAD may have imbalances in certain neurotransmitters, for example dopamine and serotonin, these affect energy levels and mood.

Vitamin D deficiency: We require sunlight to produce vitamin D, this vitamin has been linked with mood and energy levels. Therefore a reduction in sunlight can lead to vitamin D deficiency, impacting mood.

Other factors: There are a number of things that can contribute to the development of SAD. For example, a history of depression or other mental health conditions, stress, and changes in sleeping and eating patterns due to the change in seasons.

How Phinity Therapy Can Help

At Phinity Therapy you can expect to receive highly individualised care. This means that we will start by gathering information about you and your lifestyle during your Initial Assessment. We will also want to learn about your experience of SAD and the ways in which it impacts you. This will allow us to work with you in designing our highly individualised treatment plan.


For example, you may wish to manage your mood and behaviour in a practical way, and for this we might talk to you about cognitive behavioural therapy (CBT). Alternatively, you might like to understand some of the other factors that have affected your development of SAD. We would therefore recommend one of the more deeper diving psychological approaches.


This can help you gain insight into yourself and your experience of life, but also move toward healing and therefore lessen the impact. Or, if you prefer we could integrate a few talking therapies to help you with the different ways in which SAD manifests for you.

What Causes SAD?How Phinity Therapy Can Help


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