Seasonal Affective Disorder

Seasonal Affective Disorder (SAD) is a form of depression linked to reduced daylight during autumn and winter.
SAD affects an estimated 2 million people in the UK, with many more experiencing milder "winter blues" symptoms.
Construction workers are particularly vulnerable because they often travel to and from site in darkness.
Symptoms include persistent low mood, loss of motivation, difficulty concentrating, fatigue, and disturbed sleep.
Other signs can include increased appetite, weight gain, social withdrawal, and irritability with colleagues.
SAD is caused by reduced sunlight affecting the brain's production of serotonin and melatonin hormones.
The condition typically starts in October or November and improves in March or April as daylight increases.
Mental health conditions are the second most common cause of work absence in the UK construction sector.
SAD is a recognised medical condition — your GP can provide diagnosis, treatment, and support options.
Untreated SAD reduces concentration and alertness, which directly increases accident risk on construction sites.

Site safety impact	Reduced concentration, slower reactions, and fatigue caused by SAD directly increase the risk of accidents and errors on site.
Workforce wellbeing	Construction has the highest suicide rate of any UK industry — recognising and supporting mental health conditions saves lives.
It is treatable	SAD responds well to treatment including light therapy, exercise, and medication — early action makes a significant difference.

Do

Don't

Learn to recognise the symptoms of SAD in yourself and your workmates.
Spend time outdoors during daylight hours, especially during lunch breaks on site.
Speak to your GP if you experience persistent low mood every winter season.
Consider using a SAD light therapy lamp for 30 minutes each morning at home.
Maintain regular exercise — even a short walk in daylight improves mood significantly.
Talk to your supervisor or site mental health champion if you are struggling.
Check in on colleagues who seem withdrawn, tired, or unlike their usual selves.
Ensure welfare cabins and rest areas are well lit during the winter months.
Eat regular balanced meals and reduce reliance on sugar, caffeine, and alcohol.
Access the company employee assistance programme for confidential support and counselling.

DON'T dismiss persistent winter low mood as normal — it may be a treatable condition.
DON'T use alcohol as a coping mechanism — it worsens depression and disrupts sleep.
DON'T isolate yourself from colleagues — social connection is protective for mental health.
DON'T ignore changes in a workmate's behaviour — ask if they are okay privately.
DON'T skip meals or rely on energy drinks to compensate for tiredness and low energy.
DON'T be embarrassed to seek help — SAD is a medical condition, not a weakness.
DON'T assume tiredness and poor concentration are just caused by long winter hours.
DON'T mock or belittle anyone who talks about their mental health on site.
DON'T work through exhaustion without telling your supervisor how you are feeling.
DON'T wait until symptoms are severe — early intervention produces the best outcomes.

See also: Mental Health and Wellbeing on Site | Fatigue Management and Working Hours

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