Working with SAD: Seasonal Affective Disorder Symptoms and How to Support Staff

Seasonal affective disorder (SAD), often called winter depression, is a type of depression that follows a seasonal pattern, most commonly starting in the autumn or winter and resolving during the spring and summer. Rethink Mental Illness states that around 1 in 15 people in the UK experience SAD every winter. Search data shows a 236% rise in searches for ‘seasonal affective disorder’ in the past three months, indicating that people are experiencing the symptoms now that the temperature has dropped and are looking for guidance. 

In this guide, we’ll cover the most common seasonal affective disorder symptoms, what causes them and how they show up at work. We’ll also share practical ways you can support your team through the darker months.

What are the Symptoms of Seasonal Affective Disorder?

SAD symptoms usually start in autumn, build through winter and ease in spring. They’re similar to other types of depression, but they follow the seasons. According to the NHS, common signs include:

Mood

• low mood
• losing interest in things you usually enjoy
• feeling guilty, hopeless or worthless

Energy, sleep and appetite

• feeling more tired and sleeping more than usual
• feeling hungrier and eating more than usual
• a lack of energy

Behaviour

• difficulty concentrating
• feeling restless or irritable
• not wanting to see people

Some people also have thoughts of suicide or self-harm. If an employee tells you this, encourage them to speak to their GP or call NHS 111 straight away. They can also call Samaritans free on 116 123, day or night. If someone is in immediate danger, call 999.

What Causes SAD?

Although the exact causes of SAD are still being studied, it is primarily triggered by reduced exposure to sunlight during autumn and winter. Scientists attribute the condition to four main factors:  

• Disrupted circadian rhythm (internal body clock): The body uses natural sunlight to regulate its internal 24-hour clock, aiding sleep patterns, energy levels, and mood. When daylight hours drop, this internal clock falls out of sync.
• Reduced serotonin production: Serotonin is a key neurotransmitter that regulates mood, appetite, and focus. As sunlight stimulates serotonin production, the shorter winter days lower serotonin levels.
• Overproduction of melatonin: Melatonin is the hormone that makes us feel sleepy, and darkness triggers its release. The extended darkness in autumn and winter causes the brain to overproduce melatonin, worsening tiredness.
• Vitamin D deficiency: The skin produces vitamin D when exposed to sunlight, which plays an essential role in supporting serotonin activity. Low sunlight exposure during winter frequently leads to vitamin D deficiency. Recent search data shows that searches for ‘vitamin D supplements’ have increased by 22% in the past three months, showing that more people are trying to increase their vitamin D intake ahead of the winter months. Our workplace vitamin D testing helps staff find out if their levels are low before winter sets in.

Together, these changes cause seasonal affective disorder symptoms such as low energy, oversleeping, irritability, low mood and overeating.

How Does SAD Affect Employees at Work?

Seasonal affective disorder symptoms can make daily life difficult, and they can be especially hard to manage at work. Serotonin drops and internal clock disruptions can cause brain fog, poor memory retention and low concentration, meaning tasks that usually take thirty minutes could need double the time. These SAD symptoms can also increase error rates due to the difficulty of processing information.

SAD can also lead to absenteeism. According to the CIPD’s Health and Wellbeing at Work 2025 report, mental ill health is the leading cause of long-term absence. Melatonin overproduction can also contribute to lateness, as it can make waking up physically difficult.

Many face the afternoon slump throughout the year, but it hits much harder in winter. While this habit usually occurs around 3 pm, it can happen much earlier in winter as natural light disappears more quickly. With less motivation and confidence, employees might focus on low-effort and less important tasks. 

SAD can increase presenteeism, too, where employees continue to work despite being physically or mentally unwell, but operating at a fraction of their normal capacity. Left unchecked, presenteeism can tip into burnout. Our guide on how to prevent burnout at work covers the early warning signs. 

SAD can also affect team dynamics, with employees being less likely to participate in meetings or group discussions and heightened irritability causing friction.

Is SAD More Common in Women?

Interestingly, women are diagnosed with SAD four times more often than men. While researchers are still studying the exact combination of mechanisms, the biological, hormonal, and social factors that drive this disparity are:

• The oestrogen-serotonin connection: Oestrogen helps regulate the production and processing of serotonin, but hormone fluctuations during menstrual cycles, perimenopause, pregnancy, and postpartum can lower baseline serotonin levels. This, tied with the reduced sunlight in winter, lessens serotonin levels even further.
  
• Difference in melatonin and the internal clock: Studies have shown that women often experience higher sensitivity to light-driven circadian disruptions. Fluctuating ovarian hormones also often suppress or disrupt sleep cycles, so this combination with overproduction of melatonin can cause severe fatigue and mood slumps in more women than men.
  
• Co-occurrence with other hormone-related conditions: Women experiencing premenstrual dysphoric disorder (PMDD), postpartum depression, thyroid issues, and more show significantly higher rates of SAD, as these underlying conditions already strain the nervous system, so reduced seasonal daylight can exaggerate the existing vulnerabilities.
  
• Reporting and diagnosis bias: Women are statistically more likely to consult GPs about mental health symptoms, low mood and lack of energy, which can result in higher official diagnosis rates. Men experiencing SAD might mask symptoms through irritability, overworking, or substance use rather than seeking medical help for fatigue or low mood, creating underdiagnosis in men.

How Employers Can Support Employees Dealing with SAD

Employers can support employees dealing with SAD by improving their working environment and helping them feel heard and understood. Strategies to support include:

Improve Lighting and Maximise Natural Light

Many offices use bright fluorescent lighting, which can cause eye strain and vision issues, as well as headaches and migraines. As this harsh lighting emits blue-spectrum light that suppresses melatonin production, it can affect sleep and increase fatigue, too. Prolonged exposure is also linked to increased mental exhaustion, lower alertness, and heightened feelings of anxiety or sluggishness. 

Instead of fluorescent lighting, employers could opt for alternatives, such as task lighting, light diffusers, or dedicated desk-based therapy lamps. ‘SAD lamps’ have seen a 653% increase in searches in the past three months, and ‘light therapy box’ has seen a 129% increase in the same time period, showing that more people are seeking ways to combat the reduced natural light going into the darker months.

These types of lighting can mimic natural sunlight, boosting serotonin levels to help lift moods and energy levels and realign our internal clock. According to a survey, office workers who work standard 9-to-5 hours during peak winter months receive less than 30 minutes of natural sunlight a day, including their commute and lunch breaks. Of course, employees can go out for lunch, but with the cold weather, many would likely eat in the office. So, maximising natural light by opening all blinds and potentially moving desks closer to windows can help employees.

Create Comfortable Breakout Spaces

Having quiet areas away from desks where employees can take a break can help them combat the brain fog and fatigue that comes with SAD. These spaces can also facilitate low-pressure conversations with colleagues and can help reduce any feelings of isolation. Changing posture and moving around can help counter the sluggishness, too. 

For these breakout spaces, the design is important. Incorporating the Scandinavian ‘Hygge’ style, which prioritises cosiness with warm lighting, soft and comfy furniture, and natural tones, can help boost moods. Biophilic design is also great for combating stress, as it connects indoor spaces to nature, helping lower cortisol and improve moods. Maximising natural light and integrating plant walls and natural materials and textures can create the perfect breakout space.

Flexible Hours and Working Patterns

Starting and ending the day when it’s dark is a huge factor impacting SAD, as it confuses our internal body clock, which can make us feel more tired, both in the morning and the afternoon. Offering flexible working patterns can help combat this, allowing employees to start and finish at varying times. For example, employees could start work at 8 am and finish at 4 pm or start at 10 am and finish at 6 pm. This way, they might get a little bit more daylight either in the morning or the afternoon. 

Offering more remote work could also help employees with SAD, as it allows more flexibility to gain natural sunlight exposure between tasks and get some fresh air. While office workers could access natural light during their lunch break, they may opt not to if it’s raining, or they have a busy or time-sensitive workload. Eliminating the commute also provides more time for a slower, self-care morning. Additionally, remote workers can create a working environment that suits their needs, such as working in a room with more natural light, using desk-based therapy lamps or wearing more comfortable clothing.

However, there is a risk of employees feeling more isolated whilst remote working, which is already a symptom of SAD, so it’s important to monitor this where possible and have initiatives in place, such as dedicating some social time in team meetings.

Mental Health Support and Resources

It’s always important for a business to have mental health support for employees, such as Mental Health First Aiders, forums and drop-ins, and Employee Assistance Programs (EAP). If employers haven’t already got these benefits and initiatives in place, it’s worth considering, as they can really help employees struggling with SAD.

If they are already in place, employees should be encouraged to use them. While over 84% of UK businesses now offer an EAP, average utilisation rates hover between just 10% and 12%, according to the Employee Assistance Professionals Association UK. This low usage rate may be due to employees either forgetting or not knowing the service exists, or feeling hesitant to reach out. Reminding staff about these resources ahead of winter ensures that early signs of SAD are addressed before they escalate into long-term absence. 

Talking to somebody, such as a mental health first aider, allows employees to open up in a compassionate, non-judgemental conversation. Mental Health First Aiders are also equipped to spot early signs of SAD and provide informed support and advice.

However, employees may feel more comfortable using EAPs, services provided independently by third-party specialists, which allow workers to talk to somebody outside the business. EAPs offer longer-term support and solutions, such as cognitive behavioural therapy, as well as 24/7 help lines for immediate access to counsellors during low points.

Supporting Your Team Through Winter

Ultimately, aiding employees with SAD comes down to empathy, flexibility, and awareness. Recognising that winter challenges are rooted in biology rather than a lack of effort allows leaders to offer meaningful support when it is needed most. When employees feel understood and cared for through the darkest months, they return to spring stronger, more engaged, and deeply connected to their team. 

Want to put a winter wellbeing plan in place? Get in touch to talk about training, health checks and support for your team.

Seasonal Affective Disorder FAQs