Dementia
Progressive decline in memory, thinking and function severe enough to affect daily life.
Overview
Dementia is an umbrella term — Alzheimer's disease, vascular, Lewy body and frontotemporal dementias being the most common. Early diagnosis allows planning, symptom treatment and access to disease-modifying therapy where appropriate.
Symptoms
- • Memory loss affecting daily activities (especially recent events)
- • Difficulty with familiar tasks or words
- • Disorientation in time and place
- • Mood, personality or behaviour changes
- • Visual-spatial difficulties; falls
Risk factors
- • Age (doubles every 5 years after 65)
- • Family history, APOE-ε4 in Alzheimer's
- • Hypertension, diabetes, smoking, obesity, alcohol
- • Hearing loss (untreated)
- • Low physical and cognitive activity, social isolation, depression
- • Head injury
Causes
- • Alzheimer's pathology (amyloid + tau)
- • Cerebrovascular disease
- • Alpha-synuclein (Lewy body, Parkinson's)
- • Tau / TDP-43 (frontotemporal)
- • Reversible mimics: hypothyroid, B12 deficiency, depression, NPH, medication effects
🚨 Red flags — seek urgent care
- • Rapid (weeks) cognitive decline
- • Focal neurological signs
- • Acute confusion — exclude delirium / infection
- • Suicidal ideation or carer crisis
When to seek care
- • Memory or thinking change affecting function
- • Concerns from family rather than the patient (typical pattern)
- • Driving safety concerns
Diagnosis
- • Cognitive assessment (MoCA, ACE-III, GPCOG)
- • Bloods: FBC, U&E, calcium, glucose, HbA1c, LFT, TFT, B12/folate, vitamin D
- • Structural imaging (MRI preferred); FDG-PET or DaTscan in selected cases
- • CSF biomarkers or amyloid PET in specialist memory services
- • Differentiate subtype (Alzheimer / vascular / Lewy body / FTD)
Treatment
- • Treat cardiovascular risk factors aggressively
- • Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) in mild-to-moderate Alzheimer's, Lewy body
- • Memantine in moderate-to-severe Alzheimer's
- • Anti-amyloid antibodies (lecanemab, donanemab) in selected early Alzheimer's where licensed
- • Manage BPSD (behavioural and psychological symptoms) non-pharmacologically first
- • Advance care planning, lasting power of attorney, carer support
Prevention
- • Control BP, glucose, lipids; treat hearing loss; avoid head injury; stop smoking
- • Mediterranean diet, regular exercise, social and cognitive engagement
- • Lancet 2024: ~45% of dementia cases are linked to 14 modifiable risk factors
Complications
- • Falls and fractures
- • Aspiration pneumonia
- • Malnutrition and dehydration
- • Carer burnout
Prognosis
Variable by subtype — Alzheimer's typically 8–10 years from diagnosis. Early diagnosis and risk-factor control measurably extend independent years.
Education & self-care
Dementia is not a normal part of ageing. Early assessment unlocks treatment, planning and support that improve outcomes for both patients and families.
Frequently asked questions
Is forgetfulness always dementia?
No. Normal age-related memory change is mild and stable. Dementia progresses and affects function.
Can dementia be prevented?
Not entirely, but up to ~45% of risk is linked to modifiable factors — BP, hearing, activity, smoking, alcohol, education.
Is dementia the same as Alzheimer's disease?
Alzheimer's is the most common cause of dementia (about two-thirds of cases). Other types include vascular dementia, Lewy body dementia and frontotemporal dementia, each with different progression and treatments.
Do current medications stop progression?
Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) and memantine modestly improve symptoms but do not halt disease. New disease-modifying antibodies (lecanemab, donanemab) slow decline in early Alzheimer's.
What helps reduce risk?
Hearing aids, blood pressure control, regular exercise, social engagement, sleep, alcohol limits and not smoking together account for a substantial proportion of preventable dementia risk.