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DESCRIPTION: According to the AOK Absenteeism Report 2026, the number of days lost due to burnout rose by 77 per cent over a ten-year period. What the figures reveal, why burnout is not classified as an illness under the ICD, and what this means for the debate on sick leave.

Burnout: The diagnosis that isn’t really a diagnosis

The AOK’s 2026 Absenteeism Report predicts a 77 per cent increase in days lost to burnout over the next ten years. The headline fits a year in which the Chancellor has publicly questioned whether so many sick days are ‘really necessary’. Both sides of the debate are discussing a category that is not recognised as a medical condition. To understand what the figures are telling us, we need to clarify what is being counted, what burnout means in diagnostic terms, and why exhaustion has been treated as a moral issue since the Middle Ages.

What the 2026 Absenteeism Report reveals

The AOK Scientific Institute (WIdO) presented the report on 8 October 2026. It analyses sick leave among employees insured by the AOK and this year focuses on ‘Strengthening mental health in the workplace’.

The key figures:

· Overall sickness absence is falling slightly. In 2025, there were 23.3 days of absence per AOK member, down from 24.5 in 2022. In the first half of 2026, the figure was even lower.

· The number of days lost due to mental health conditions rose from 284 per 100 members in 2016 to 403 in 2025, an increase of just under 42 per cent.

· In 2025, an absence due to a mental health condition lasted an average of 28.5 days. An absence due to a respiratory illness lasted 5.7 days.

· Absence days with a diagnosis of burnout rose from 11.0 to 19.5 per 100 members, an increase of 77 per cent.

· Employees in dialogue marketing – that is, in call centres – were absent most frequently, followed by home and family care, care for the elderly, therapeutic care and childcare.

· In 2025, health insurance funds provisionally paid out 21.6 billion euros in sickness benefit. Ten years earlier, the figure was 11.2 billion.

How significant is the proportion attributable to burnout?

That 77 per cent sounds like a significant surge. A look at the absolute figures puts this into perspective. For every 100 members, there are 19.5 days of absence due to burnout compared with 403 days due to mental health conditions. Burnout thus accounts for just under five per cent of days lost due to mental health issues.

The majority of absences are caused by diagnoses that are rarely mentioned in media reports. According to the report, ‘reactions to severe stress and adjustment disorders’ are the leading cause of absenteeism, followed by depressive episodes and recurrent depressive disorders. The press refers to it as the ‘burnout report’ because everyone is familiar with the term. The figures in the report primarily relate to depression and stress-related reactions.

Absenteeism does not measure the prevalence of mental illness

Psychiatrist Steffi Riedel-Heller from the University of Leipzig notes in the report that absences are an important indicator, but not a direct measure of the prevalence of mental illness in the population. This statement was lost in the media coverage, even though it is what makes the figures meaningful in the first place.

A sick note depends on more than just the illness. It depends on whether someone goes to the doctor, whether they describe their condition as mental, whether the doctor codes it as such, and whether the employer is shown the diagnosis. Each of these steps has changed over the past ten years. Mental health conditions are less stigmatised, doctors are more likely to identify mental health issues as such, and many patients now say themselves that they are exhausted and feeling low.

There is also a technical factor at play. The electronic certificate of incapacity for work has been in force since 1 July 2022. Since then, health insurance funds have been recording sick notes that previously never reached them. The WIdO explicitly attributes the surge in sick leave from 2022 onwards to this more comprehensive recording.

Is burnout an ICD diagnosis?

In the ICD-10-GM, which German doctors use for coding, burnout is listed under Z73 ‘Problems relating to difficulties in coping with life’. This category includes ‘burnout’ alongside ‘a state of total exhaustion’, stress and ‘lack of relaxation or leisure time’. The WHO version of the ICD-10 has a separate subcode for this: Z73.0 ‘Burnout’. Chapter Z covers factors that influence health status and lead to the use of healthcare services. A Z code describes a reason for contacting a doctor. In 2012, the DGPPN recommended that it be assigned additionally when a mental health condition stems from excessive demands at work.

The ICD-11 clarified the situation in 2019. The World Health Organisation classifies burnout under QD85 in Chapter 24, ‘Factors influencing health status or contact with health services’, in the section on problems relating to work or unemployment. It defines it as a syndrome resulting from chronic, unresolved stress in the workplace, with three characteristics: exhaustion; a growing sense of detachment or cynicism towards one’s own work; and a feeling of being ineffective and unable to achieve anything. The WHO states that burnout is ‘not classified as a medical condition’. The term applies exclusively to the occupational context and should not be applied to other areas of life. Adjustment disorders, stress-related disorders, anxiety disorders and mood disorders are expressly excluded. If any of these conditions are present, they are coded and QD85 is omitted.

The category showing the strongest growth in the report is therefore the only one that, according to both classifications, does not denote a disease.

Burnout and depression: what is the difference?

Research has so far failed to identify a clear-cut distinction. In 2015, Renzo Bianchi, Irvin Schonfeld and Eric Laurent analysed 92 studies on the overlap between burnout and depression. Their conclusion: the distinction is conceptually tenuous. Above all, it remains unclear how the final stage of burnout is supposed to differ from clinical depression. More recent studies tend to question whether burnout is a distinct condition in its own right. There are no standardised diagnostic criteria.

In 2012, the German Society for Psychiatry and Psychotherapy (DGPPN) proposed a practical distinction. According to this, burnout is not an illness but represents ‘a risk state for subsequent mental or physical illnesses’. Anyone who goes on to develop depression, an anxiety disorder or an addiction as a result has a condition requiring treatment, and this condition needs to be diagnosed. The DGPPN cites previous episodes of depression, anxiety disorders and addictions as risk factors.

This explains the popularity of the term. ‘Burnout’ implies that someone has been working hard, and therefore sounds less like a failure than ‘depression’. Many patients prefer to describe their condition as burnout, and some doctors code it as such. The colloquial term ‘exhaustion depression’ combines both concepts and is also not an ICD diagnosis.

When burnout masks depression

The WHO definition itself provides the most important distinguishing feature: burnout is limited to work. The typical symptoms of burnout syndrome are emotional exhaustion, cynicism towards work and the feeling of being unable to make a difference despite one’s best efforts. Anyone who no longer experiences any joy even whilst on holiday, at the weekend or during their free time; anyone who feels an inner emptiness and lack of motivation; anyone who wakes up early in the morning and cannot get back to sleep; anyone who loses weight, feels worthless or has thoughts of death is highly likely to be experiencing a depressive episode. Sleep disturbances and physical complaints such as headaches or back pain occur in both conditions and are not useful for distinguishing between them.

Phase models are popular, such as the twelve phases of burnout attributed to Freudenberger and Gail North. These are based on clinical observation and have hardly been empirically studied. What counts for the diagnosis is the current state.

This makes a significant difference to treatment. Depression responds to psychotherapy, such as cognitive behavioural therapy, and, where necessary, to antidepressants. The first point of contact for professional help is often the GP. Taking time out on its own rarely cures it, and anyone who returns unchanged after three weeks’ rest should take this as a sign. People who refer to their depression as ‘burnout’ often wait too long.

Merz and the issue of sick days

In mid-January 2026, at an election campaign event in Bad Rappenau, Friedrich Merz commented on employees’ sick leave: “That’s almost three weeks during which people in Germany are not working due to illness.” He asked: “Is that really right? Is it really necessary?” On the subject of sick notes issued over the phone, he said: “It was justified during the Covid-19 pandemic – but is it still justified today?” On 14 January, at the New Year’s reception hosted by the Halle-Dessau Chamber of Industry and Commerce and the Halle Chamber of Crafts, he repeated what he had already said in May 2025 at the CDU Economic Council’s Business Day: “We will not be able to maintain our prosperity with work-life balance and a four-day week.”

The Absenteeism Report responds to this with data. Sick leave is falling. Part of the rise since 2022 is due to more comprehensive data collection. An AOK study from 2025 found no evidence of systematic abuse of telephone sick notes. What is on the rise are long-term absences due to depression and stress-related conditions, and these primarily affect the care sector, the education sector and call centres. People in these sectors who are absent are often off work for weeks at a time.

What the survey reveals about worries and exhaustion

The report includes a survey of employees. Those who are worried about their financial situation or fear losing their jobs are more likely to report feelings of despondency, anger and exhaustion. WIdO Managing Director Helmut Schröder expects these pressures to intensify given the current economic climate and to manifest later in absenteeism.

This means the debate itself becomes part of the problem. A government that demands more work and casts doubt on sick leave is increasing precisely the uncertainty that the survey links to exhaustion.

Acedia, neurasthenia, burnout: exhaustion as a moral question

The question of whether exhaustion is an illness or a weakness of character has a long history. In the 4th century, the monk Evagrius Ponticus described acedia, the ‘midday demon’ that assails monks in their cells: weariness, restlessness, the feeling that time stands still. In the 13th century, Thomas Aquinas defined it as sadness over spiritual matters. In lists of the deadly sins, it became sloth; in popular parlance, laziness. Anyone who was exhausted had sinned.

In 1869, the American physician George Miller Beard described neurasthenia, or nervous exhaustion. He attributed it to the pace of modern life – the railway, the telegraph and competition. Neurasthenia was regarded as an affliction of the capable, of businesspeople and scholars. Around 1900, it filled the psychiatric hospitals in Germany. The historian Joachim Radkau calls this period ‘The Age of Nervousness’.

In 1974, the psychoanalyst Herbert Freudenberger published his essay ‘Staff Burn-Out’. Whilst working at an alternative, free clinic in New York, he had observed how dedicated staff members became tired, irritable and cynical after a few months. He adopted a term for this condition that, in colloquial usage, referred to the consequences of chronic drug use. Building on this, Christina Maslach, together with Susan Jackson, developed the Maslach Burnout Inventory in 1981, which continues to shape research to this day.

The three terms assign blame and credit differently. Acedia was a sin of the individual. Neurasthenia was a badge of honour for those who kept pace with the times. Burnout presupposes that someone has been ‘burnt out’. Merz’s question about sick days brings the debate back to acedia.

The Society of Fatigue

In 1998, the sociologist Alain Ehrenberg described depression as an illness of a society that demands of the individual that they be themselves and shape their own lives on their own terms. His book was published in German as *Das erschöpfte Selbst* (*The Exhausted Self*). Those who fail at this task experience it as a personal shortcoming.

Byung-Chul Han took this idea a step further in 2010 in *The Society of Fatigue*. According to Han, the ‘performance subject’ exploits themselves, without an external master, and is both perpetrator and victim in one. Exhaustion then becomes a sign that someone has given their all. This explains why ‘burnout’ is an easier label to utter than ‘depression’.

Both analyses have a weakness that the Absenteeism Report highlights. Most absences occur in elderly care, call centres and nurseries. Han’s ‘performance subject’, who overexerts themselves of their own free will, is hard to find in these settings. These professions lack staff, funding and recognition.

Key points at a glance

• The 2026 Absenteeism Report forecasts a 77 per cent increase in days lost due to burnout and just under a 42 per cent increase due to mental health conditions over the next ten years. Overall sickness absence is falling.

• Burnout accounts for just under five per cent of mental health-related days off. Most absences are due to stress-related reactions, adjustment disorders and depression.

• Absenteeism figures do not measure how common mental health conditions are. They also depend on how doctors classify cases, how openly mental health issues are discussed, and, since 2022, on the use of electronic sick notes.

• According to ICD-10 (Z73) and ICD-11 (QD85), burnout is not a disease. The WHO describes it as a work-related phenomenon and excludes it as a diagnosis as soon as depression or an adjustment disorder is present.

• Scientifically, it is almost impossible to distinguish between burnout and depression. Anyone who no longer finds joy in life outside work is likely to be suffering from depression and should seek treatment.

• The debate over sick leave raises an age-old question. Acedia, neurasthenia and burnout each assign blame and credit in different ways.

Sources

· AOK Federal Association (2026): Absenteeism due to mental health conditions has risen by 42 per cent over ten years. Press release on the 2026 Absenteeism Report, 8 October 2026. https://www.aok.de/pp/bv/pm/fehlzeiten-report-2026/

· AOK: Mental Health Absenteeism Report. https://www.aok.de/pp/gg/update/fehlzeiten-report-psyche/

· World Health Organisation (2019): Burnout as an ‘occupational phenomenon’: International Classification of Diseases. https://www.who.int/news/item/28-05-2019-burn-out-an-occupational-phenomenon-international-classification-of-diseases

· Bianchi, R., Schonfeld, I. S., Laurent, E. (2015): Burnout-depression overlap: a review. Clinical Psychology Review 36, 28–41. https://doi.org/10.1016/j.cpr.2015.01.004

· Berger, M., Falkai, P., Maier, W. (2012): The world of work and psychological stress: Burnout is not an illness. Deutsches Ärzteblatt 109(14), A 700–702. https://www.aerzteblatt.de/archiv/124719

· BfArM: ICD-10-GM 2026, Z70–Z76. https://klassifikationen.bfarm.de/icd-10-gm/kode-suche/htmlgm2026/block-z70-z76.htm

· WHO: ICD-10 Version 2019, Z73.0. https://icd.who.int/browse10/2019/en#/Z73.0

· WHO: ICD-11 MMS 2025-01, QD85 Burnout. https://icd.who.int/browse/2025-01/mms/en#129180281

· Freudenberger, H. J. (1974): Staff Burn-Out. Journal of Social Issues 30(1), 159–165. https://doi.org/10.1111/j.1540-4560.1974.tb00706.x

· Maslach, C., Jackson, S. E. (1981): The measurement of experienced burnout. Journal of Occupational Behaviour 2(2), 99–113. https://doi.org/10.1002/job.4030020205

· Maslach, C., Schaufeli, W. B., Leiter, M. P. (2001): Job Burnout. Annual Review of Psychology 52, 397–422. https://doi.org/10.1146/annurev.psych.52.1.397

· Beard, G. M. (1869): Neurasthenia, or nervous exhaustion. Boston Medical and Surgical Journal 80(13), 217–221. https://doi.org/10.1056/NEJM186904290801301

· Radkau, J. (1998): The Age of Nervousness. Germany between Bismarck and Hitler. Munich: Hanser.

· Ehrenberg, A. (2004): The Exhausted Self. Depression and Society in the Present Day. Frankfurt am Main: Campus.

· Han, B.-C. (2010): The Fatigued Society. Berlin: Matthes & Seitz.

· ZDFheute (2026): Merz criticises high sickness absence rates and sick notes issued over the phone. https://www.zdfheute.de/politik/deutschland/krankmeldung-krankenstand-merz-kritik-100.html

· LTO (2026): Merz’s initiative on the labour force debate: Work more, be ill less? https://www.lto.de/recht/nachrichten/n/zu-viele-krankheitstage-telefonische-au-arbeitszeitgesetz-merz-kritik

· dubisthalle.de (2026): New Year’s reception hosted by the Chamber of Industry and Commerce and the Chamber of Crafts with Chancellor Merz at the Händelhalle, 15 January 2026. https://dubisthalle.de/neujahrsempfang-von-ihk-und-handwerkskammer-mit-bundeskanzler-merz-in-der-haendelhalle/

· Tagesspiegel (2025): Merz criticises the four-day working week and work-life balance, 14 May 2025. https://www.tagesspiegel.de/politik/merz-kritisiert-vier-tage-woche-und-work-life-balance-wir-mussen-in-diesem-land-wieder-mehr-arbeiten-13687588.html