January marks the formal restart of work after the festive shutdown, but it also marks a predictable decline in mental health for a significant proportion of the workforce. Seasonal Affective Disorder (SAD) is a clinically recognised depressive condition linked to reduced daylight exposure during winter months. Its symptoms include low mood, fatigue, sleep disturbance, impaired concentration, and reduced motivation. From a health and safety perspective, these symptoms directly affect alertness, decision making, reaction time, and compliance with procedures. Under UK health and safety law, psychological harm and work-related stress are recognised hazards. Treating the “January blues” as a cultural inconvenience rather than a safety risk exposes organisations to preventable incidents, near-misses, and long-term sickness absence.
CASE STUDY
During the winter of 2021-2022, a UK manufacturing and distribution organisation identified a marked deterioration in safety performance during January and February. The business operated warehouse, manual handling, and vehicle-movement activities, all of which required sustained concentration and procedural discipline.
Following a two-week Christmas shutdown, supervisors reported a pattern of concern across several departments rather than a single isolated incident. These included increased absenteeism, presenteeism, fatigue, withdrawal, and a noticeable rise in operational errors. Internal safety data showed an increase in near-miss reports, particularly involving manual handling tasks, pedestrian vehicle interface areas, and quality-critical checks.
Rather than attributing the issue solely to post-holiday disengagement, the organisation referred multiple employees to occupational health. Assessments identified Seasonal Affective Disorder in several cases. Employees described classic SAD symptoms: persistent low mood, poor sleep, difficulty concentration, reduced commuting and working almost entirely in darkness, limited daylighted exposure, and difficulty re-establishing routine after Christmas.
No serious injury occurred; however, the organisation formally recorded winter related mental health decline as a contributing factor within its stress risk assessment. This approach aligned with HSE guidance recognising work-related stress, depression, and anxiety as leading causes of occupational ill health, accounting for over half of all reported cases nationally.
Health and Safety Hazards Identified
The case study highlights hazards that are foreseeable, seasonal, and relevant across multiple sectors:
· Reduced concentration and cognitive processing, increasing error likelihood.
· Fatigue and sleep disruption affecting reaction time and situational awareness.
· Presenteeism, where employees attend work while mentally impaired
· Reduced engagement with safety procedures and checks
· Increased risk in safety critical roles involving machinery, vehicles, lone working, or hazardous substances.
· Lack of managerial awareness leading to delayed intervention.
Control Measures Implemented
Following occupational health recommendations and internal review, the organisation implemented proportionate control measures:
· Updated stress risk assessments to explicitly include winter and January mental health risks.
· Mandatory wellbeing check-ins during the January return-to-work period.
· Manager training on recognising early indicators of seasonal depression.
· Improved workplace lighting and maximised daylight exposure where possible.
· Temporary flexibility in start times and workloads during winter months
· Clear signposting to occupational health services and employee assistance programmes
Legal duties
· In 2026, UK health and safety law treats mental health with the same weight as physical safety. Under the Health and Safety at Work etc. Act 1974 and subsequent regulations, employers have the following primary duties regarding seasonal depression (SAD).
· Duty of Care: Employers must ensure, "so far as is reasonably practicable," the health, safety, and welfare of all employees, which explicitly includes protecting them from psychological harm.
· Risk Assessments: Under the Management of Health and Safety at Work Regulations 1999, employers must conduct "suitable and sufficient" risk assessments for psychosocial hazards. For seasonal depression, this means identifying how winter-specific factors (e.g., lack of light, increased workload pressures) might impact staff well-being.
Management Standards: The Health and Safety Executive (HSE) require employers to manage six key areas that affect stress and mental health:
Demands: Managing workload and work environment.
Control: Giving employees a say in how they work.
Support: Providing adequate resources and management check-ins.
Relationships: Preventing conflict or harassment.
Role: Ensuring clear responsibilities.
Change: Communicating organisational changes effectively.
Safety-Sensitive Adjustments: For employees in high-risk sectors (e.g., construction or transport), employers must assess if seasonal depression symptoms—like fatigue or poor concentration—affect the safe operation of machinery or vehicles.
SUMMARY
Seasonal Affective Disorder is not an abstract wellbeing topic; it is a predictable occupational health risk with measurable safety implications. The absence of a single reportable accident does not negate risk. Near-miss trends, performance degradation, and occupational health referrals provide credible evidence of exposure. January represents a convergence of reduced daylight, psychological strain, and operational pressure. Organisations that integrate seasonal mental health into health and safety planning demonstrate legal compliance, risk foresight, and operational maturity. Organisations that ignore it rely on chance rather than control.
