Mental Health Sick Leave: What UK Employers Need to Know

Mental health absence isn’t just a personal issue, it’s a strategic challenge for HR and leadership teams and organisations as a whole. Ignoring the issues caused by poor mental health (or handling it poorly) drives up absence costs and increases the risk of legislative breaches, all while weakening workforce resilience.

However, if organisations implement a strong wellbeing policy, compliance can be maintained while simultaneously reducing absence and ensuring a faster, safer return to work.

The commercial impact of mental health absence

It may seem obvious that workforce absences would have a negative impact on an organisation, and leadership teams understand this. However, many overlook the impact of poor mental health and how it can lead to greater absence rates.

In fact, poor mental health is now the leading cause of long-term workplace absence and only second to minor illnesses for short-term absences. The impact is clear to see across the UK:

Costs and productivity: It is reported that 22.1 million days lost in 2024/25 to workrelated stress, depression or anxiety with 964,000 people experiencing symptoms.

Compliance risk: Mental health conditions must be treated the same as physical illness. Mishandling mental health absence, failing to act on fit note advice, or refusing reasonable adjustments can breach the Equality Act 2010. If a mental health condition meets the Equality Act 2010 disability definition, organisations must consider reasonable adjustments.

Leadership bandwidth: Long-term absence disrupts teams and slows delivery. Early intervention and structured return-to-work processes, such as fit notes, can reduce time away and support safer reintegration. Fit notes are required after 7 calendar days of absence and can be issued by healthcare professionals and occupational therapists.

Common mental health conditions that drive absences

Whilst there are a myriad of reasons and conditions such as PTSD, OCD, bipolar disorder, etc. that can drive mental health related absences, the most common causes are stress, anxiety and depression.

In some cases, causes can be driven by workplace conditions and expectations. Whether it is heavy workloads, stressful environments, or a lack of support, organisations and their leadership teams may not only be missing the key signs of poor mental health.

To ensure mental health is supported, HR and leadership teams need to know the key indicators and symptoms to look out for. These may include:

• Fatigue

• Social withdrawal

• Performance dips

• Regular lateness

• Emotional volatility

• Team interactions

Failing to address this may not only lead to more absences, it can also disrupt team morale, dynamics and engagement.

Your Duty of Care: What employers must provide

Under UK law and legislative acts, organisations must make reasonable adjustments to protect the health, safety and wellbeing of individuals in the workforce. This includes safeguarding the mental health of their people.

To do this effectively, organisations must treat mental and physical health equally to prevent discrimination and ensure compliance. For mental health absences, this means:

• Taking concerns seriously

• Using fit notes proactively and following expert guidance on sickness processes

• Considering reasonable adjustments for mental health conditions, whether they meet the conditions for the Equality Act disability definition as good practice

• Conducting and updating stress risk assessments where work factors are contributing

UK legal compliance: Mental health, disability and sick pay

Mental health in the workplace is not only an operational issue, but also one of legislative compliance. This only becomes tougher and more complicated to manage when poor mental health and stress lead to a workplace absence.

The Equality Act 2010: When is mental health a disability?

Under the Equality Act 2010, a mental health condition is classed as a disability if it has a substantial and long-term adverse effect (typically 12 months or more) on normal day-to-day activities.

If this is the case for an individual in the workforce, organisations must consider reasonable, and often, necessary adjustments. Examples of this include:

• Flexible hours

• Quiet or isolated workspaces

• Role or task adjustments

• Flexible working hours

• Temporary relocation if necessary

The Health and Safety at Work Act 1974

The piece of legislation which dictates that organisations and their leadership teams have a duty of care to safeguard their workforce is the Health and Safety at Work Act 1974. This act is all-encompassing for people’s health and welfare, including their mental health.

This means managing psychological risks such as excessive work-related stress. This may involve putting relevant and effective support measures in place and identifying mental health hazards under the Management of Health and Safety at Work Regulations 1999 to control and eliminate them.

Statutory Sick Pay (SSP)

Eligible employees off sick are entitled to Statutory Sick Pay (SSP) for up to 28 weeks, at the government set weekly rate, and this also covers mental health related absences. Some organisations may offer enhanced contractual sick pay. The impact of SSP is set to worsen as the changes from the Employment Rights Act 2025 come into effect.

From April 6th 2026, waiting days and lower earning limits for SSP will be removed and that the rate of SSP will be 80% of an individual’s earnings or the current flat rate, depending on which is lower. This could have huge and costly implications for organisations that fail to manage workforce mental health as now absences could be more expensive than ever. Fit notes

Fit notes

When a person is absent from work, whether it be due to a physical injury, injury, etc. or a mental health related absence, they are required to self-certify for the first 7 calendar days. From day 8, a fit note is required.

Since 2022, fit notes can be issued by doctors, nurses, pharmacists, physiotherapists and occupational therapists. Digital versions are also valid. These fit notes can be treated as a workplace conversation starter, not clearance. Discuss the healthcare professional or occupational health advisors’ guidance and agree upon temporary adjustments or a phased return. Here are a few key practices regarding fit notes from a HR perspective:

• Log fit‑note details; confirm adjustments in writing; set a review date

• If symptoms are work‑related, complete/refresh a stress risk assessment

• Where appropriate, refer for Occupational Health advice to clarify capacity, restrictions and timescales

Reasonable adjustments for mental health

No two people are the same, and any mental health conditions could affect them completely differently. It is for this very reason that it is recommend that any adjustments made for workforce mental health reasons need to be tailored and reviewed over time. This may involve assessing:

Working patterns: Flexible hours, phased returns, shorter but more frequent breaks, protected time for therapy/medical appointments

Workload responsibilities and assignments: Temporary reduction in caseloads or deadlines, breaking work into shorter tasks, timeboxing cognitively demanding work

Environment & communication: Quieter workspace, agreed communication modes (e.g., fewer unscheduled calls) and regular 1:1 check-ins

Adjustments reduce legal risk and enable safer, faster returns to work and thus cut the number of workplace absences, in turn preserving productivity rates and operational efficiency.

Managing “Stress Leave” in the UK

Stress is a key cause of declining mental health rates and workplace burnout. This can quickly spiral and result in a workplace absence. When this happens, it needs to be reported as an instance of work-related stress or the individual needs to be signed off with stress. Here are some of the processes and positive practices that should be fulfilled in the case of ‘stress leave’:

1. Acknowledge and record concerns: do not downplay or dismiss any concerns.

2. Agree a contact plan while off: frequency of contact, preferred channel, and helpful suggestions or accommodations (avoid over contact).

3. Use fit note advice to plan either continued absence or a safe return-to-work.

5. Assess work factors such as demands, role clarity, relationships with colleagues and leadership teams and mitigate concerns where possible.

6. Consider OH advice for complex, recurrent or long-term cases and document instances, accommodations and risks.

This approach reduces risk, supports recovery and demonstrates procedural fairness if capability processes are later required

Return to work

When an individual has been absent from work for an extended period (typically over 8 working days), a return-to-work meeting is essential. These meetings can help leadership and HR teams determine whether a person if fit to fulfil their roles after an absence.

This becomes especially poignant after a mental health absence. If someone has been struggling with excessive stress, anxiety or depression, their working conditions could have brought his on and led to the absence. Therefore, it is vital to conduct a return-to-work interview to determine if they can fulfil their responsibilities, and if there are any concerns, that they can be addressed and actioned (within reason).

Throughout the meeting, HR professionals and line managers should focus on:

• Current symptoms

• Functional capacity

• Temporary adjustments

• Review cycle, and points of contact

If necessary, a phased return may need to be considered, along with a written plan. Use NHS guidance to set expectations (e.g., individuals can return before the fit note end date if able and if adjustments are in place).

Where internal capability is limited, an Occupational Health assessment can clarify realistic timelines, restrictions and adjustments, while EAP counselling provides rapid access to support that shortens absence.

How an EAP Reduces Mental Health Sick Leave

Mental health related absences are on the rise. With them now leading the way in long term absences and second only to common illnesses for short-term workplace absences, it is not an issue that can be ignored. Finding a reliable solution to this issue requires accessible and reliable support from experts.

Your organisation needs proactive and reactive support to ensure that mental health absences are reduced and managed effectively. HA | Wisdom Wellbeing’s Employee Assistance Programme (EAP) is clinically accredited and designed to reduce the risks of workplace stress and poor mental health to prevent higher costs and extended workplace absences.

With HA | Wisdom Wellbeing’s EAP, your organisation can access:

• 24/7/365 access to qualified counsellors for short‑term, solution-based counselling to ensure a smooth and rapid recovery for reduced absences and fewer operational disruptions.

• HR advice line and management support to guide confident, compliant support, signposting and reliable decisions on adjustments as well as confidence on secure conversations around mental health concerns. Where appropriate (complex or recurrent cases)

• Occupational Health Assessments to clarify fitness, restrictions and timescales

• Virtual GP access to reduce delays in medical advice and fit‑note conversations, speeding up safe decisions.

The Outcome of using our service is a reduction in the amount of mental health absences and their duration as well as stronger wellbeing policies and processes to ensure legislative compliance, and a healthier, safer culture.

FAQs

What should we do immediately when an employee reports work‑related stress? Acknowledge; record; agree a contact plan; signpost support; review workloads and triggers; and, if off sick, use fit‑note advice to plan adjustments or phased return. Where appropriate, carry out/refresh a stress risk assessment.

How do we stay compliant when managing mental health absence? Follow effective and established absence processes; use fit notes properly; consider reasonable adjustments where indicated; document decisions; avoid discriminatory treatment; and seek Occupational Health input where capacity is unclear.

Can an individual be signed off for “stress” and for how long? Yes. “Stress” can be cited on a fit note where it affects fitness for work. Duration depends on clinical judgment; in the first 6 months, a fit note can cover up to 3 months at a time. Currently, SSP is available for up to 28 weeks if an individual is eligible.

If a fit note states “may be fit for work,” does an individual have to return to the workplace? No. Discuss the clinician’s advice and decide if adjustments are practicable. If not, treat as “not fit for work” and continue absence support. Ensure the rationale is documented.

Is depression a disability — and what does that change for us? Often, yes. If the Equality Act test is met, organisations have a legal duty to consider reasonable adjustments and to avoid discrimination, harassment or victimisation linked to disability.

Can you get a fit note for anxiety in the UK? Yes. Any condition that affects fitness for work can be certified, including anxiety. Focus on the advice section: it may enable a supported return rather than prolonged absence.

Do we need medical evidence for the first week of absence? No. Individuals self‑certify for the first 7 calendar days; from day 8, a fit note is required.