Discussion

This service evaluation has quantified the increasing pressure under which Leicester YODAS has been managing, a pressure that continues to escalate. Referrals to YODAS have almost doubled between 2020 and 2024, while service provision capacity has remained unchanged. The rise in referrals locally is reflective of broader national trends, with memory services continuing to see rising volumes of primary care referrals for people under the age of 65. ^{Reference Sikdar, Bhattacharyya and Mukherjee8} This trend may reflect heightened public awareness of dementia, with research showing that 58% of patients and 71% of next-of-kin are concerned that cognitive symptoms of any nature may represent the onset of dementia, thus increasing referrals from the so-called ‘worried well’ population. ^{Reference Sutherland, Kirk, Karunanayake, O’Connell and Morgan9} This has been further exacerbated over the past 5 years by cognitive impairment in post-COVID-19 syndrome (‘long COVID’), ^{Reference Arbula, Pisanu, Bellavita, Menichelli, Lunardelli and Furlanis6,Reference Herrera, Pérez-Sánchez, San Miguel-Abella, Barrenechea, Blanco and Solares7} placing the current service model under sustained and critical pressure.

Across the UK, YOD services vary considerably in structure and scope, ranging from those incorporated within generic all-age ‘memory clinic’ models, to purely diagnostic services, to those offering post-diagnostic follow-up and personalised care planning. Specialist YOD services have consistently been associated with superior patient outcomes, such as improved continuity of care, quality and patient satisfaction. ^{Reference Stamou, La Fontaine, Gage, Jones, Williams and O’Malley5} There is therefore an expectation that these services provide high-quality assessments while also maintaining acceptable waiting times from referral to diagnosis.

Despite this, the period from referral to diagnosis in dementia remains long. Although there is agreement that targeted strategies are urgently needed to improve diagnostic timelines, it is equally important to consider how systems within specialist services are structured to manage increasing referral volumes while maintaining the quality of care expected. This is in line with the recommendations outlined in Royal College of Psychiatrists’ report on mental health service provision for young-onset dementia. ¹⁰

A key quantitative indicator of the strain experienced by YOD services is the increase in waiting times. According to the National Audit of Dementia (NAD) Spotlight Audit (2023–24), the mean waiting time from referral to first appointment has increased from 66 to 88 days, and from referral to diagnosis from 124 to 151 days across all dementias. ¹¹ The 2019 benchmark for referral to YOD diagnosis was 13 weeks; ^{Reference Souris12} however, locally, the average wait from referral to first YODAS assessment had increased to 19 weeks by August 2024 (M.C. and E.B.M.-L. personal communication), and continues to rise.

Comprehensive assessment for suspected YOD is inherently resource intensive, requiring multidisciplinary input and a broad differential diagnostic work-up to distinguish between neurological, psychiatric and systemic aetiologies ^{Reference Rayment and Kuruvilla4} An audit of a memory assessment service in Cornwall quantified this workload at approximately 4 h of combined clinical and administrative time per assessment. ^{Reference O’Kelly, Richards and Figueroa Gorospe13} These findings raise an important question regarding sustainability: how can a service designed for a relatively low-prevalence condition maintain assessment quality in the context of increasing demand?

Previous work has suggested a high likelihood of service saturation if strategies for adequate screening were not explored. ^{Reference O’Kelly, Richards and Figueroa Gorospe13} At the same time, the diagnostic complexity of cognitive presentations in younger adults significantly increases the risk of both under- and over-diagnosis, especially where symptoms overlap with pre-existing mental illness, intellectual disability or functional disorders. ¹⁰ These challenges have important implications for service efficiency and the appropriate use of specialist resources.

Much of the existing research on YOD services in the UK has focused on the experiences of individuals who ultimately receive a diagnosis of young-onset dementia. However, those who receive a diagnosis represent a relatively small proportion of those referred to specialised memory services. Data from the 2019 National Memory Service Audit indicate that among patients under the age of 65 accepted for assessment by memory services, 23% were diagnosed with dementia. Of those not diagnosed with dementia, 40% received no formal diagnosis, while others were diagnosed with MCI (17%), a primary psychiatric disorder (15%) or functional cognitive disorder (FCD) (6%). ^{Reference Souris12} Multiple local studies further illustrate the heterogeneity of presentations in YOD clinics and the relatively low proportion of referrals that ultimately result in a dementia diagnosis. ^{Reference Sikdar, Bhattacharyya and Mukherjee8} This highlights the critical role of triage and the need to consider outcomes for those who are declined specialist assessment.

This increasing group of individuals with non-organic cognitive complaints, referred to memory services in search of clarification or reassurance, has received little attention. If memory is problematic, there are more frequent concerns about ageing and the potential for dementia, ^{Reference Cahill, Gibb, Bruce, Headon and Drury14} and many have been told that a referral has been made on their behalf to the ‘memory services for younger people’. Uncertainty among clinicians as to the scope of local YOD services creates further variability in referrals. ^{Reference Steiner, Ee, Dubois, MacMillan, George and McBride15}

In our region, the service was formally renamed from ‘Young Person’s Memory Service’ to ‘Young Onset Dementia Assessment Service’ (YODAS) in 2018, a change intended to reflect its specialist diagnostic remit. Despite this, it continues to be perceived by both referrers and patients as a generic ‘memory clinic’ for younger people. There is often an expectation that YOD services function as a single, supportive point of contact for all cognitive concerns in individuals under 65 – a perceived ‘one-stop-shop’ model. ^{Reference Steiner, Ee, Dubois, MacMillan, George and McBride15} When this expectation is unmet, outcomes can be disappointing. Many individuals are declined before formal assessment because the likelihood of an underlying neurodegenerative process is considered low, leaving this cohort without clear explanations or defined pathways for addressing their ongoing cognitive difficulties.

Our evaluation identified several gaps in local referral pathways, particularly for individuals whose cognitive symptoms are attributable to non-neurodegenerative causes. There may be opportunities for improved identification and management of alternative conditions such as FCD. ^{Reference Sikdar, Bhattacharyya and Mukherjee8} FCD is frequently encountered in memory clinic populations, is estimated to account for 12–56% of new referrals to specialist memory clinics and remains under-recognised in routine practice. ^{Reference Ball, McWhirter, Ballard, Bhome, Blackburn and Edwards16} Distinguishing FCD from early neurodegenerative MCI has been described as a core challenge in cognitive services, ^{Reference Ball, McWhirter, Ballard, Bhome, Blackburn and Edwards16} increasing the risk of diagnostic uncertainty and inappropriate investigation or management. ^{Reference Cabreira, Frostholm, McWhirter, Stone and Carson17} We find that individuals with FCD then go from pillar to post between different specialties, ^{Reference Ball, McWhirter, Ballard, Bhome, Blackburn and Edwards16} none of which are equipped to treat them.

A substantial number of referrals were not accepted owing to ongoing harmful alcohol consumption, as patients are usually expected to reduce alcohol consumption before a formal cognitive assessment can take place. Although Leicester has an alcohol and drug service (Turning Point), its main objective is behavioural intervention, and there are no clear pathways for the assessment of cognitive impairment arising from chronic alcohol consumption. Similarly, those with a prior diagnosis of alcohol-related brain damage were not accepted into the service in the same context.

The same pattern emerged in referrals for patients with fibromyalgia: cognitive symptoms that featured prominently in these referrals were complaints of fatigue, attention difficulties and mental slowness – symptoms commonly referred to as ‘fibrofog’. Although there was clinical merit in making a diagnosis that such presentations were not neurodegenerative, alternative local pathways for assessment and management for individuals presenting with these cognitive symptoms remain to be developed.

There were further gaps in local neurorehabilitation services and limited awareness of services that existed to support patients with a history of brain injury or post-stroke cognitive decline. In these situations, cognitive problems were more likely related to past neurological events than to a new degenerative process; however, referral to memory services resulted because clear alternative pathways did not exist. All in all, the lack of clear pathways for non-degenerative cognitive disorders has left the memory clinics as a default pathway for any cognitive concern in younger adults.

Follow-up of individuals whose referrals were not accepted by YODAS showed that only 6% subsequently received a diagnosis of dementia, indicating that the majority of those not accepted were appropriately directed away from the specialist neurodegenerative pathway. It is equally important, therefore, that alongside raising awareness and promoting timely referral of young people with memory concerns, clear guidance be developed to ensure that only appropriate patients are referred to specialist secondary care services.

The situation is complicated by the fact that the currently recommended cognitive screening tests for primary care ¹⁸ are not validated for use in younger people with suspected YOD. ^{Reference Mukaetova-Ladinska, Abdullah, Critchfield and Maltby19} Instruments such as the GPCOG may also lack validity in culturally and linguistically diverse populations or in individuals with limited literacy, in whom poor performance may reflect sociodemographic factors rather than cognitive decline. ^{Reference Hilsabeck, Benge, Scott, Thotakura, Rana and Schmitz20} Cognitive screening tools also lack discriminant validity in distinguishing depressive cognitive symptoms from early neurodegeneration. Previous local YODAS research demonstrated that incorporating a brief mood measure, such as the four-item Geriatric Depression Scale (GDS-4), into primary care screening may facilitate earlier identification and treatment of depression, reducing unnecessary referrals to memory services. ^{Reference Abdullah, Critchfield, Maltby and Mukaetova-Ladinska3}

In November 2022, the Leicester, Leicestershire and Rutland Living Well with Dementia Strategy gathered views from people with young-onset dementia and their carers to inform the Supporting Well Strategy for 2024–2028, including an objective to refresh YOD pathways. ²¹ It is hoped that the findings of this evaluation will inform ongoing pathway development and integrated care planning.

Lack of scrutiny and adaptation in response to growing referral pressures may lead to saturation in YOD services, even longer waiting times and potentially delayed care for individuals with YOD. We encourage YOD services across the UK to invest in the development of dedicated, consultant-led triage. Moreover, collaboration with partner agencies, including NHS Talking Therapies service, neurorehabilitation services, chronic pain and pain management services, and addiction services, is crucial in developing formal pathways for non-degenerative cognitive disorders.