DeNPRU-QM Responsive project: Prevalence of memory complaints in the absence of objective symptoms in clinical populations: systematic review update

Background – Current pathways for assessment and treatment of memory disorders are designed for people with dementia but are also accessed by people with subjective cognitive decline without objective deficits (SCD), or with cognitive deficits likely to be of psychological causation without neurodegeneration (Functional Cognitive Disorders, FCDs). We aimed to identify how frequently adults meeting SCD/FCD criteria, arguably better served by different service models, present to health services. Methods – Updating a previous review, we searched MEDLINE, Embase, and PsycINFO for studies reporting SCD/FCD prevalence within representative clinical samples, published between 2019 and 2025. We assessed study quality using the RoB-PrevMH tool and synthesised data using similar methods to the previous review. Results – We included 5/21 high- and 16/21 moderate-quality studies. The pooled mean age was 73.3 years (Standard Deviation = 7.0; N = 12,785) and 55.1% of participants were female. Across studies reporting SCD (k = 20; n = 13,155) and FCD (k = 3; n = 4,551), pooled prevalences were 17.3% and 5.6% respectively. Most studies (k = 11; 52.4%) did not explicitly exclude pseudodementia related to psychiatric illnesses. In high quality studies that did, SCD prevalence was 11.4% ( k  = 3, n = 3,295; 10.2–14.1%) in memory clinic attendees and 16.5% ( k  = 1, n = 91) among primary care attendees aged 50 + presenting with cognitive complaints without pre-existing dementia. Conclusions – At least 10% of people presenting to memory services are diagnosed with SCD and fewer with FCD. We need consistent guidelines about how these conditions are defined and diagnosed. An integrated, multidisciplinary, neighbourhood health service would be well positioned to treat these groups.