Meaning and boundaries
Seasonal affective disorder describes depression with a recurring pattern associated with particular seasons. It may follow a winter pattern or, less commonly, a summer pattern. Assessment belongs with healthcare professionals. It is not equivalent to feeling uncomfortable in a dark office and cannot be diagnosed from the location of somebody’s desk.
Occupational prevention should ask two different questions: whether the environment provides suitable visual working conditions, and whether somebody needs an individual adjustment for health reasons. Combining them can lead to calling a room «depressing» as if this were a diagnosis, attributing every energy problem to windows, or demanding medical proof before repairing a light. Environmental improvements can benefit workers without turning every complaint about lighting into a medical problem or requiring disclosure of personal health information.
Sources: [1]
What the research can establish
A case-control pilot study published in 2014 compared office workers with different access to windows and daylight. It found differences in measures of sleep and wellbeing. The observational design does not establish that a lack of windows causes seasonal depression or that installing a window treats a disorder.
For building decisions, this distinction matters: an association may justify examining the environment, but it does not replace the technical assessment of a particular workplace. Task allocation, working schedules and personal circumstances may also affect the experience of a working day. A refurbishment proposal should explain which problem it intends to address and which outcome can actually be checked, avoiding the presentation of an architectural change as a guaranteed clinical intervention.
Sources: [3]
Three dimensions to assess separately
Visibility enables someone to distinguish a label, detect an obstacle or read a screen. Visual comfort includes reflections, contrast and discomfort during prolonged tasks. Light exposure also interacts with circadian rhythms; its effects depend on timing, not simply on whether a lamp is brighter.
A useful assessment separates these dimensions in its records. «I cannot read the printed references clearly» calls for a check of the task and its visual conditions. «The sun reflects on the screen halfway through the morning» requires attention to orientation and shading. «I have persistent difficulties sleeping» may require access to a healthcare channel. None of these statements alone establishes seasonal affective disorder, and several different problems can coexist at a single workstation. Recording the actual difficulty is more useful than choosing a diagnostic label.
The prevention framework in Spain
Within its scope, Annex IV of Spain’s Royal Decree 486/1997 requires lighting to suit the activity and the risks associated with visibility. It gives preference to natural lighting where possible and provides for artificial lighting when daylight is insufficient. Glare and other effects that interfere with perception also need to be addressed.
Practical application requires identifying what people do and where they do it, rather than assigning one lighting value to an entire company. A circulation route, a precision task and a display screen do not present identical circumstances. The assessment record should retain the criterion used, the measurement conditions and the actions required. This Spanish regulation must not be presented as a universal legal requirement for workplaces located in other jurisdictions.
Sources: [2]
Reviewing a workstation and its surroundings
As an organisational starting point, a walkthrough can involve people who use the space at different times. Record screen positions, shiny surfaces, blinds, shadowed areas and failing lights. Observe actual work: a photograph of an empty desk at midday does not necessarily represent early morning tasks or winter conditions.
Competent personnel then determine the relevant measurements and checks. A record may include the area, task, time, outdoor conditions, available controls and a concrete description of the difficulty. A simple issue map helps distinguish a shared problem from an isolated workstation concern. Individual preferences should be heard, but they do not replace technical checks or justify leaving an unsafe condition unresolved. The review should also establish whether occupants can genuinely use the controls provided, rather than merely noting that those controls exist.
Sources: [2]
Design and organisational measures
Selected measures may combine furniture rearrangement, protection from direct sunlight, reflection control, repair of fittings and adjustment options compatible with the task. Before moving desks closer to a window, check that the change will not introduce excessive heat, obstructions or a screen facing a source of glare. The aim is suitable conditions throughout the actual working day.
Where access to daylight areas is limited, break spaces and break arrangements can be reviewed if the activity permits. Such proposals should include support staff and people working in internal areas. A window should not become a reward allocated by seniority. Facilities and prevention teams should agree the solution, including its budget, maintenance arrangements and a date for checking whether it addresses the original problem. Access must be workable for those expected to benefit.
Sources: [2]
Shifts, schedules and treatment boundaries
NIOSH explains that light influences circadian synchronisation and that the timing of exposure matters. An indiscriminate recommendation for «more light at any time» therefore does not constitute a shift management programme. Night work requires competent consideration of the task, schedule and rest arrangements together.
Office lighting must also be distinguished from clinical light therapy. Purchasing a lamp marketed as healthy does not make its collective use an appropriate treatment. Where an employee follows healthcare advice, the organisation can explore compatible adjustments without prescribing light doses or requesting unnecessary details. Facilities decisions should be recorded as environmental decisions, while clinical decisions remain in the appropriate healthcare channel. A workplace purchasing process should not be used to bypass individual assessment or to promise a health outcome that has not been demonstrated.
Individual adjustments without exposing health data
A person may report a need to review their workstation or schedule without explaining their clinical history to the whole team. A useful management practice is to offer a clear contact, describe relevant functional requirements and agree which information each responsible person needs to implement the adjustment. A change of location should not be announced using a diagnostic label.
It is also useful to set a review point: check whether the adjustment supports work, whether it has created other difficulties and whether it needs modification. Action should not depend on colleagues accepting a public medical explanation. When environmental issues and individual requests share a software system, access and purposes should be separated so that a maintenance report does not acquire identifiable clinical information. Staff should understand which channel is appropriate for each concern.
Sources: [5]
A hypothetical workplace example
An administrative team on an internal floor reports visual tiredness and requests «lamps against winter depression». The prevention team explains that these complaints do not establish a seasonal disorder. Its review identifies reflections on several screens, deteriorated fittings and a daylit break room that is frequently occupied by meetings.
The organisation repairs the installation, trials a different screen arrangement and reserves usable break periods. It also provides a confidential channel for individual needs. Before and after the changes, it asks about specific reading difficulties and reflections under comparable conditions. Results are reported as improvement or persistence of environmental problems, without claiming cures, inventing a number of clinical cases prevented or extending the findings to every office without windows. The remaining issues receive named owners and a further review date.
Useful indicators and measurement mistakes
A monitoring record can include workstations assessed, outstanding issues, repair times, subsequent checks and effective availability of planned controls. Worker feedback may ask whether blinds can be adjusted or whether tasks can be completed without troublesome reflections. These are measures of conditions and organisational response, not tests for a disease.
Compare similar periods and record refurbishment, occupancy changes and the season. Fewer complaints after a move may have several explanations and should not automatically become a percentage improvement in mental health. It is also inappropriate to classify employees by «seasonal sensitivity» using productivity, absence or desk location. Monitoring should enable correction of the working environment, rather than surveillance of intimate personal characteristics. A good report makes clear both what improved and what its evidence cannot establish.
Integration into occupational safety and health
This topic connects with lighting assessment, display screen work, visual fatigue and shift organisation. A preventive record should preserve the identified problem, the measure, its owner, the deadline and verification evidence. The description needs to be specific enough for maintenance personnel to act without interpreting a general comment about wellbeing.
When commissioning refurbishment, request acceptance criteria relevant to the planned tasks and verify them after occupation. Photographs can document reflections or layouts while avoiding personal information displayed on screens. A seasonal review helps detect circumstances absent on the handover date. Learning from the case should inform the design of new workstations and the planning of later changes. This creates continuity between purchasing, facilities management and prevention rather than treating lighting complaints as disconnected individual preferences.
Sources: [2]
Frequently asked questions
Does working without windows cause seasonal affective disorder?
A direct relationship cannot be assumed. Diagnosis requires clinical assessment and a pattern of symptoms. A lack of windows warrants environmental review but does not establish a disorder.
Does more light always mean better conditions?
No. The task, reflections, contrast, exposure timing and the characteristics of people and schedules also matter.
Can an employer prescribe light therapy?
Employers should improve working conditions and facilitate relevant adjustments. Light treatment belongs to individual healthcare assessment, rather than a general purchasing decision.
What should prevention records contain?
Workstation conditions, technical checks, actions and verification. Clinical information should remain separate from general facilities records.
