When the Seasons Affect Our Mood

 

As autumn gives way to winter, the days become shorter, natural daylight decreases and our daily routines begin to change. For some people, this seasonal transition brings changes in energy, motivation and mood.

While many experience occasional feelings associated with the winter blues, others experience more persistent and disruptive symptoms linked to Seasonal Affective Disorder (SAD).

Understanding how seasonal changes can affect our physical and psychological wellbeing is an important step towards recognising when additional support may be needed.

What Is Seasonal Affective Disorder?

Seasonal Affective Disorder (SAD) is a form of depression that follows a recurring seasonal pattern. Symptoms most commonly develop during autumn or winter and improve during spring or summer.

Although winter-pattern SAD is more common, some people experience depression during the warmer months, known as summer-pattern SAD.

SAD is more than simply disliking cold weather or darker evenings. Symptoms can affect everyday activities, relationships, work and overall quality of life.

Common symptoms include:

  • Persistent low mood or sadness

  • Loss of interest in previously enjoyable activities

  • Tiredness and reduced energy

  • Changes in sleep patterns, including oversleeping

  • Increased appetite or cravings for carbohydrates

  • Difficulty concentrating

  • Feelings of hopelessness, irritability or withdrawal

Symptoms vary between individuals and may range from mild to severe.

The Discovery of Seasonal Affective Disorder

Our modern understanding of SAD developed through the pioneering research of psychiatrist Dr Norman E. Rosenthal and colleagues at the National Institute of Mental Health in the United States.

After experiencing changes in his own energy levels during the darker winter months, Rosenthal became interested in how seasonal variations in daylight might influence mood.

In 1984, Rosenthal and his colleagues published research describing Seasonal Affective Disorder and preliminary findings on the use of bright-light therapy.

Their work helped establish the importance of investigating seasonal patterns in depression and encouraged further research into the relationship between light exposure, biological rhythms and psychological wellbeing.

Today, SAD is recognised as a form of depression with a seasonal pattern, although researchers continue to investigate its underlying causes and the effectiveness of different treatments.

How Does Seasonal Change Affect Our Mood?

Our bodies respond to environmental changes, including variations in temperature, daylight and the timing of sunrise and sunset.

Daylight plays an important role in regulating the body's internal biological clock, known as the circadian rhythm.

This approximately 24-hour rhythm helps coordinate sleep, alertness, hormone activity and other essential bodily functions.

A small region of the brain called the suprachiasmatic nucleus (SCN), located within the hypothalamus, helps regulate this process by responding to information about light received through the eyes.

During winter, shorter daylight hours can affect the timing of these biological processes. Researchers believe that such changes may contribute to the development of SAD in some individuals.

Three areas have received particular attention.

Serotonin and Mood

Serotonin is a neurotransmitter involved in regulating mood, sleep and appetite.

Research suggests that seasonal changes in daylight may affect serotonin-related processes in the brain. However, the relationship is complex, and SAD cannot be explained simply as a serotonin deficiency.

Melatonin and Sleep

Melatonin is a hormone involved in regulating the sleep-wake cycle.

Its production is influenced by light and darkness. Changes in the timing of melatonin release may help explain why some people experience increased sleepiness, difficulty waking or changes in energy levels during winter.

Vitamin D and Sunlight

Vitamin D is produced naturally by the body when the skin is exposed to sunlight. Levels may decrease during the winter months when sunlight exposure is limited.

Researchers have explored whether vitamin D deficiency contributes to SAD, but findings remain mixed. Vitamin D deficiency has not been established as a direct cause of the condition.

Together, these areas illustrate how biological, environmental and psychological factors may interact to influence seasonal mood changes.

Practical Ways to Support Wellbeing During Winter

Although SAD may require professional treatment, everyday wellbeing practices can help support mood, energy and daily functioning.

1. Make the Most of Natural Daylight

Spending time outdoors during daylight hours can help support the body's natural rhythms.

A short daytime walk, sitting near a window or making use of available natural light may be beneficial.

Even on cloudy days, outdoor daylight can provide greater light exposure than many indoor environments.

2. Establish a Consistent Routine

Maintaining regular sleeping and waking times can help support the body's internal clock.

Establishing routines around meals, physical activity and rest may also provide structure during months when reduced daylight affects motivation.

3. Keep Physically Active

Regular movement can support physical and psychological wellbeing.

Walking, swimming, stretching or taking part in an enjoyable physical activity can provide opportunities to manage everyday stress and maintain a sense of routine.

Outdoor exercise also provides an opportunity for natural daylight exposure.

4. Maintain a Balanced Diet

A varied, balanced diet supports general health and energy levels.

Including fruit, vegetables, whole grains, protein and healthy fats can contribute to overall wellbeing.

If you are concerned about vitamin D levels or supplementation, seek advice from a pharmacist or healthcare professional.

5. Stay Connected

During darker months, reduced motivation may make it tempting to withdraw from everyday activities.

Maintaining contact with family, friends and community groups can provide opportunities for encouragement, connection and emotional support.

6. Recognise When You Need to Recharge

Seasonal changes can affect our energy and daily routines.

Paying attention to changes in sleep, concentration, motivation and mood can help us recognise when we may need to adjust our activities or seek additional support.

Rest is important, but so is maintaining meaningful activities and social connections.

Treatment and Professional Support

Seasonal Affective Disorder is a recognised form of depression, and effective support is available.

Depending on individual circumstances, treatment may include talking therapies, antidepressant medication and other approaches recommended by a healthcare professional.

Cognitive Behavioural Therapy (CBT) can help individuals explore patterns of thinking and behaviour that may contribute to depression and develop strategies for managing symptoms.

Light therapy involves using a specially designed light box that provides bright artificial light. Some people find this helpful, although research findings are mixed and its effectiveness is not certain.

Anyone considering light therapy should seek medical advice first, particularly if they have an eye condition, take medication that increases light sensitivity or have another condition that could affect its suitability.

If symptoms of low mood persist, affect daily life or return during particular seasons, speaking to a GP is an important step.

Understanding Our Responses to Seasonal Change

Seasonal Affective Disorder highlights the relationship between our environment, biological processes and psychological wellbeing.

Although we cannot control the changing seasons, we can develop greater awareness of how changes in daylight, routines and activity may affect us.

Recognising these changes creates opportunities to make informed choices about our daily habits, seek support and take practical steps towards maintaining our wellbeing.

At Balance UK encourages individuals to develop self-awareness and practical stress-management strategies through The At Balance Method.

While stress-management techniques are not a treatment for SAD, understanding our responses to change can form part of a wider approach to supporting everyday wellbeing.

As the seasons change, taking time to recognise and respond to our needs remains an important part of maintaining balance.

At Balance UK — Supporting Your Wellbeing

References and Further Reading

  1. Rosenthal, N. E., et al. (1984). Seasonal affective disorder: A description of the syndrome and preliminary findings with light therapy. Archives of General Psychiatry, 41(1), 72–80. https://doi.org/10.1001/archpsyc.1984.01790120076010

  2. National Institute of Mental Health. Seasonal Affective Disorder. https://www.nimh.nih.gov/health/publications/seasonal-affective-disorder

  3. NHS. Seasonal affective disorder (SAD). https://www.nhs.uk/mental-health/conditions/seasonal-affective-disorder-sad/

  4. NICE. Depression in adults: treatment and management (NG222). https://www.nice.org.uk/guidance/ng222

  5. Melrose, S. (2015). Seasonal affective disorder: An overview of assessment and treatment approaches. Depression Research and Treatment, 2015, Article 178564. https://doi.org/10.1155/2015/178564

This article is intended for general education and wellbeing awareness and does not replace professional medical advice.