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Disability: Stammering starting in adulthood

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This page does not apply outside Great Britain.
Last updated 24th March 2021 (part update 27th January, 2023).


  • This website focuses mainly on developmental stammering, starting as a young child. However stammering can also start in adults, due to a stroke or other neurological trauma or disease, a psychological trauma or depression, as a result of certain drugs, or for unknown reasons. Below Introduction.
  • With any stammer, to be a disability it must have a substantial (ie more than minor or trivial) effect on one’s ability to carry out normal day-to-day activities: see separate ‘Disability’ main page.
  • However if the stammering starts in adulthood, there is the further question of whether the substantial adverse effect is ‘long-term’ (below). ‘Long-term’ normally means at least 12 months, so it is fine if the effect has already lasted 12 months at the time of the discrimination.
  • If the substantial effect hasn’t yet lasted 12 months when the discrimination happened, the ‘long-term’ test is met if the effect “could well” last that long. Medical evidence (below) is likely to be important in showing the test is met. Whether the effect “could well” last at least 12 months is assessed as at the time of the alleged discrimination (below); it is not relevant what happens afterwards, even if by the time of the tribunal hearing it is clear that the effect has lasted that long.
  • As to the stammer being an ‘impairment’ (below), the claimant need not show what the cause of the stammer is. It does not matter if doctors and therapists cannot work out what is causing it – except that if the genuineness of the symptoms is disputed then being able to point to a cause can have evidential value to support them being genuine.
  • If a disability is caused by or made worse by the employer’s actions, perhaps an accident at work or mistreatment there, the employer may need to “go the extra mile” to accommodate the disability. Below If disability is the employer’s fault.


In some cases stammering starts in adulthood, often called “adult onset”, “late onset” or “acquired” stammering. This may be:

  • due to a stroke, trauma or other disease or condition of the brain or nervous system (neurogenic stammering). As well as Long Covid, below, an example of a neurological condition that can cause stammering and other symptoms is Functional neurological disorder (nhsinform.scot),
  • due to a psychological trauma or depression (psychogenic stammering),
  • as a result of certain drugs, or
  • “idiopathic” stammering where no cause is identifiable.

Over the last 10 years I have seen an exponential increase in clients presenting with PS [ie Psychogenic Stuttering] in my clinic and I suspect that other clinicians who have an adult caseload have observed a similar situation.
Section 17.4, Stuttering and cluttering, by David Ward, 2nd edition 2017.

Also a developmental stammer which started in childhood may re-emerge as an adult.

See ‘Developmental & acquired’ on Covert stammering.

‘Substantial effect’

As with developmental stammering which starts in childhood, there is the question of whether the stammer has a substantial (ie more than minor or trivial) effect on ability to carry out normal day-to-day activities: see ‘Disability’ main page.

Neurogenic stammering is sometimes accompanied by other speech and language disorders such as dysarthria or aphasia. If so a tribunal should consider the combined effect (eg as the EAT said in para 14 of its decision in Walker v Sita). Paragraph B6 of the Guidance on definition of disability, 2011 says that account should be taken of whether the impairments together have a substantial effect overall on the person’s ability to carry out normal day-to-day activities.

However to be a disability within the Equality Act, the substantial effect also has to be “long-term”. That should be clear in the case of a developmental stammer which has lasted many years. It may not be clear if the stammer started in adulthood:


‘Long-term’: 12 months

To be a ‘disability’ within the Equality Act, the impairment’s substantial adverse effect on normal day-to-day activities must be ‘long-term’. Basically long-term just means lasting at least 12 months (or the rest of the person’s life if shorter): EqA Sch 1 para 2. So the substantial effect is long-term if it has already lasted 12 months at the time of the alleged discrimination. The effect is also long-term if at that time it is likely to last at least 12 months from when it started.

‘Long-term’: “likely” only means “could well happen”

“Likely” does not mean more likely than not. It only means that the substantial effect could well last 12 months. This can make it significantly easier to show that the sustantial effect is “likely” to last at least 12 months.

What is the legal basis for saying “likely” has that meaning in EqA Sch 1 para 2? The House of Lords in SCA Packaging held this is what “likely” means in another provision of Schedule 1, namely para 5, and subsequent cases and the statutory guidance have given “likely” the same meaning in para 2 as well.

SCA Packaging v Boyle, House of Lords, 2009
The claimant used a voice management regime to avoid problems of vocal nodules and hoarseness. The legislation said (and says) that if her impairment would be “likely” to have a substantial effect if she did not follow that regime, it was treated as having a substantial effect so that she had a disability within the DDA. (That provision is now EqA Sch 1 para 5). The House of Lords upheld the tribunal decision that she had a disability. “Likely” meant only that her impairment “could well” have a substantial effect if she did not follow the regime. This effect did not need to be “more likely than not”.

The provision which the House of Lords considered in that case is now Sch 1 para 5 Equality Act 2010. Numerous later cases including Russell v Fox Print Services below, and also the official guidance on meaning of disability quoted below, have gone on the basis that “likely” also means “could well happen” elsewhere in Schedule 1. That includes the provision relevant here, EqA Sch 1 para 2 which says “The effect of an impairment is long-term if …(b) it is likely to last for at least 12 months…”.

Meaning of ‘likely’
C3. The meaning of ‘likely’ is relevant when determining:
– whether an impairment has a long-term effect (Sch 1, Para 2(1)…;
– whether an impairment has a recurring effect (Sch1, Para 2(2)……………
In these contexts, ‘likely’, should be interpreted as meaning that it could well happen.”
2011 Guidance on matters to be taken into account in determining questions relating to the definition of disability, para C3.

All this is consistent with Baroness Hale’s comment in SCA Packaging (above) that “likely” appears elsewhere in Schedule 1 and “it is usual for the same word to mean the same thing when used in the same group of statutory provisions”.

There is a Long Covid example below.

‘Long-term’: Medical evidence

Meeting the ‘long-term’ requirement is not a problem if the substantial effect has already lasted 12 months. If it has not lasted that long as at the time of the discrimination (see next heading), medical evidence is likely to be important in determining whether it “could well” last that long. This evidence might be from a speech and language therapist or neurologist, for example.

Medical evidence is likely to be particularly important if the case gets to a tribunal, as it will be for the claimant to show that as at the time of discrimination the effect “could well” last 12 months. It is not relevant that by the time of the tribunal hearing it is clear that the effect actually lasted 12 months (see next heading)

Since prognosis will often be uncertain, it seems likely that the “could well” test will frequently be met. Even so a tribunal may expect to see medical evidence.

‘Long-term’: Judged as at time of discrimination

Whether the definition of disability is met, including whether the substantial effect is likely to last 12 months, is judged as at the time of the alleged discrimination. What actually happens later is not relevant. By the time of the tribunal hearing it may be known that the substantial effect did or didn’t last longer than a year, but that doesn’t matter. The test is whether, considered as at the time of the discrimination, the substantial effect “could well” last at least 12 months.

Russell v Fox Print Services (bailii.org), Employment Appeal Tribunal (EAT), 2010
The claimant’s father developed a terminal illness. She was absent with depression for nearly all of the period from 28th November 2011 to 13th January 2012 when she was dismissed. The claimant’s doctor was asked: “On 13 January 2012, how long was the bout of depression likely to last?” He replied in October 2012, “This is difficult. With treatment, a bout of depression would be expected to resolve within three months of starting treatment.” The claimant requested further clarification. The doctor replied that the claimant continued to suffer significant symptoms of the depressive episode at least until the time of assessment on 31 July 2012, probably prolonged as a consequence of the interaction between the depression, her grief reaction for the death of her father and the financial pressure arising from the loss of her job.

The employment tribunal held that as at 13 January 2012, the disability had not lasted for 12 months and was not likely to last for 12 months, so it was not long-term. The doctor’s clarification was based on his assessment in July 2012, when he had the benefit of hindsight and was able to assess the reason why the depressive episode had been prolonged until that date. Importantly the doctor did not resile from his earlier statement that, as at 13 January 2012, the bout of depression would be expected to resolve within 3 months of starting treatment.

The EAT upheld the tribunal’s decision. The tribunal was entitled to decide that as at 13 January 2012 there was no real possibility (under the test in SCA Packaging above) that the symptoms would recur in the future such that they were likely to last for at least 12 months.

Likelihood of reoccurence

A substantial effect is treated as ongoing if it is likely to reoccur: see Longer-term variations. Therefore if the “substantial” effect of an impairment has ceased, say within less than 12 months, it is relevant whether a substantial effect is likely to reoccur in future. This means again whether it “could well” reoccur, considered as at the date of the alleged discrimination.


For more on the ‘long-term’ test, see Part C of the 2011 Guidance.

Note that as with developmental stammering (ie stammering from childhood), one does not need to stammer all the time for it to be a disability. See Substantial effect>Variability, and – on likelihood of reoccurence as mentioned above – Longer-term variations.

Drug-related stammering

Drug-related stammering is different in the sense that doctors may be able to switch the person onto another drug so that the stammering stops and is not long-term. However the condition for which the drug is being given may itself be a disability, with its effects being judged as they “could well” be if the drug were not being taken (see Disability: Therapy). Medical evidence is likely to be particularly important.

Long Covid

Since 2020 there are reports of Covid-19 causing stuttering, for example COVID can cause forgetfulness, psychosis, mania or a stutter (scientificamerican.com), 2021.

Matthews v CGI IT UK (pdf, gov.uk), Employment Tribunal, 2022
On the evidence, the tribunal found that as at August 2020 effects of Long Covid which had then already lasted 4 months “could well” (above) last 12 months, and so were “long-term” within the EqA. So the claimant had a disability as regards any discrimination occurring on or after a particular date in August 2020. (Stammering was not one of the effects in this case.)
Note: This is not a binding precedent, and in any event each case will depend on the evidence. The pdf linked above is the first decision linked from the case’s web page (gov.uk), 2022.


To be a “disability” within the Equality Act the stammer must be an ‘impairment‘. Hopefully this will not be disputed.

If there is a dispute on this, the Equality Act test is just whether the stammer is an ‘impairment‘, ie the focus is on its effects. See particularly Walker v Sita, 2013 where the EAT held that the claimant need not show the cause of the impairment (and also the statutory guidance quoted at that link). This case may be particularly helpful if the doctors and therapists cannot work out what is causing the stammer, perhaps calling it “idiopathic” stammering (ie the cause is unknown). Being able to show a cause may have evidential value if an employer etc argues the symptoms are not genuine, but normally there will be little doubt that they are genuine. (See though C v Spencer v Arlington below, where people at work had not perceived a stammer). In summary, it seems that provided the symptoms are genuine, the stammer should be an ‘impairment’.

So the claimant does not need to show they have a particular medical condition. Even so, it may be helpful to point out that eg ‘psychogenic stammering’ (from psychological trauma or depression) is a medical condition, or indeed that a stammer may have no known cause (ideopathic). See eg the BSA website heading ‘Developmental & acquired’ on Covert stammering. A speech and language therapist should hopefully be able to confirm this in her report if relevant.

A helpful case on depression, J v DLA Piper is discussed in Workers may find discrimination claims for depression easier after EAT ruling (archive of pinsentmasons.com). However the issues discussed in that case should not really even arise with psychogenic stammering, because with depression there is the issue of distinguishing it from ‘normal’ anxiety which anyone might have, whereas with psychogenic stammering the psychological trauma or depression has produced a stammer which is an impairment.

In one case where the claimant said he had a stammer which started in adulthood, the tribunal decided he had not shown he had a stammer/disability:

C v Spencer & Arlington, Employment Tribunal, 2019
The employment tribunal rejected a claim that an employee had a stammer which (he said) started in adulthood. He contended that the stammer was why he had raised his voice in a meeting, but he gave a different explanation at the time. He had not told the employer he had a stammer. Also the tribunal said that none of the employer’s witnesses had ever perceived a stammer. An expert’s opinion was that the claimant either had a psychogenic stammer or was malingering.

If disability is the employer’s fault

If a disability is caused by or made worse by the employer’s actions (or omissions), the employer may need to “go the extra mile” to accommodate the disability. That phrase comes from an unfair dismissal case. However it may also be relevant to the Equality Act as regards what adjustments are “reasonable”, and whether a step such as dismissal is “justified” under s.15 EqA.

Some examples of where this might be relevant:

Due to the employer’s negligence, the worker receives a blow to the head which causes a neurogenic stammer.

Bullying at work or behaviour of management leads to depression and a psychogenic stammer.

The psychological impact on an emergency worker of attending a disaster, where the employer failed to take appropriate steps to support workers afterwards, leads to a psychogenic stammer.

Even if the employer is not at fault, it might perhaps be relevant that the disability was caused by work? – eg in the final example above if the employer took all appropriate steps to support workers after the disaster.

The Court of Appeal in an unfair dismissal case agreed with the EAT judgment which said that an employer who was in some way responsible for a worker’s illness might be expected to “go the extra mile”:

McAdie v Royal Bank of Scotland (bailii.org), Court of Appeal, 2015
The claimant went off sick with stress, and the tribunal found her illness had been caused by her managers, particularly their failure to address a grievance she brought. She was dismissed. The EAT and Court of Appeal held that the dismissal was not unfair in this case, given the medical evidence was that she was unfit for work and there was no prospect of recovery. Any claim for compensation should be for personal injury in the civil courts.

However the Court of Appeal agreed with the EAT which said that where the employer is in one sense or another responsible for an employee’s incapacity, that should be relevant in deciding whether and when it is reasonable to dismiss him for the incapacity. “It may, for example, be necessary in such a case to ‘go the extra mile’ in finding alternative employment for such an employee, or to put up with a longer period of sickness absence than would otherwise be reasonable.”

In another unfair dismissal case, prior to disability discrimination legislation, the EAT also held that where a health condition was caused by work, the employer should take reasonable steps to ameliorate the problem: Jagdeo v Smiths Industries, EAT, [1982] ICR 47.

Under the Equality Act 2010, employers are in any event required to make reasonable adjustments, and disability-related dismissals (for example) need to be justified under s.15 EqA. An example of a case where a past failure of the employer – its withdrawal of an adjustment which might have avoided the sickness absence for which the claimant was dismissed – was a relevant factor for justification under the Equality Act:

Monmouthshire County County Council v Harris (bailii.org), EAT, 2015
The claimant went on sick leave after the employer withdrew homeworking arrangements made for her disabilities. The employment tribunal held that dismissing her was not justified and so was a breach of s.15 EqA. Any claim for reasonable adjustments was now out of time, and the evidence did not suggest that a return to homeworking would have helped at the time of dismissal.

The EAT held that the tribunal should reconsider its decision in favour of the claimant. The tribunal had not sufficiently taken into account that there was no continuing obligation to make a reasonable adjustment when she was dismissed.

Even so, the EAT said that in deciding whether the dismissal was proportionate, the earlier failure of the employer (the withdrawal of homeworking) could be relevant in carrying out the balancing exercise required.

There may also be grounds for a personal injury claim against the employer, ie a claim for damages in respect of the employer’s negligence, including in respect of actions of employees etc for which the employer is vicariously liable. However that is outside the scope of this website.


Not on the Equality Act, but generally about stammering starting in adulthood:

20th anniversary of stammeringlaw, 1999-2019