How Symptoms Progress

Alzheimer's symptoms usually progress slowly over several years, and can sometimes be mistaken for other conditions or simply put down to old age. The pace varies from person to person, and other things — such as infections, stroke, delirium, or certain medicines — can sometimes cause a more rapid worsening of symptoms; anyone whose symptoms deteriorate quickly should see a doctor, since there may be a treatable underlying reason.

Early Symptoms

In the early stages, the main symptom is usually minor memory lapses — forgetting recent conversations, misplacing items, forgetting names of places or objects, struggling to find the right word, repeating questions, showing poorer judgement, or becoming more hesitant about new things. Mood changes, such as increasing anxiety, agitation, or periods of confusion, are also common early signs.

Middle-Stage Symptoms

As the condition develops, memory problems worsen, and recognising family or friends can become harder. Other symptoms may include increasing confusion and disorientation (such as getting lost or losing track of time), repetitive or impulsive behaviour, delusions or feeling suspicious of carers and family, speech and language difficulties, disturbed sleep, mood swings, difficulty judging distances or spatial tasks, and hallucinations. By this stage, most people need support with everyday tasks like eating, washing, dressing, and using the toilet.

Later Symptoms

In the later stages, symptoms become more severe and distressing for both the person and those around them. Hallucinations and delusions may come and go, sometimes worsening over time, and behaviour can change further — including aggression, becoming upset or restless, or repeating the same question. Further symptoms can include difficulty eating and swallowing, difficulty moving without help, significant weight loss, incontinence, gradual loss of speech, and severe memory problems. In advanced stages, full-time care and support with eating, moving, and personal care are usually needed.

When to See a GP

See a GP if you're worried about your own memory, or think you may have dementia — if you're worried about someone else, encourage them to make an appointment, and consider offering to go with them. Memory problems aren't always caused by dementia; they can also stem from depression, stress, medicines, or other health conditions, and a GP can carry out simple checks to help identify the cause, referring you to a specialist for further tests if needed.

What Happens in the Brain

Alzheimer's is thought to be caused by an abnormal build-up of two proteins in and around brain cells — amyloid, which forms plaques around cells, and tau, which forms tangles within them. It's not known exactly what triggers this, but the process is now understood to begin many years before symptoms appear. As brain cells become affected, levels of a chemical messenger called acetylcholine drop, and over time, different brain areas shrink, usually starting with regions responsible for memory — though in rarer forms, vision or language areas are affected first instead.

Age and Family History

Age is the single biggest risk factor, with likelihood roughly doubling every 5 years past 65 — though around 1 in 20 people with Alzheimer's are under 65 (early-onset), sometimes affecting people from their 40s. Genes inherited from parents can contribute a small increase in risk, though in a few families, a single inherited gene causes a much higher risk — if dementia has affected several family members, particularly at a young age, genetic counselling can offer more personalised information.

Down's Syndrome and Head Injury

People with Down's syndrome are at higher risk, since the same genetic changes that cause Down's syndrome can also lead to amyloid build-up in the brain over time. Severe head injury may also raise risk, though more research is needed in this area.

Cardiovascular and Other Risk Factors

Lifestyle factors and conditions linked to cardiovascular disease — including smoking, obesity, diabetes, high blood pressure, and high cholesterol — are all associated with increased Alzheimer's risk. Helpful steps include stopping smoking, eating a healthy balanced diet, staying physically and mentally active, losing weight if needed, cutting back on alcohol, and having regular health checks as you get older. Other factors linked to risk, though not necessarily direct causes, include hearing loss, untreated depression (which can also be a symptom of the disease itself), loneliness or social isolation, and a sedentary lifestyle.

Seeing a GP

It's best to see a GP if you're worried about your memory, or finding planning and organising harder than usual. If you're worried about someone else, encourage them to book an appointment, and consider offering to go along — having a friend or family member present is often genuinely helpful. Memory problems can stem from many causes besides dementia, including depression, anxiety, stress, certain medicines, alcohol or drugs, and other health issues such as hormone imbalances or nutritional deficiencies.

A GP will ask about your concerns, check other aspects of your health, and may arrange blood tests and review your medicines to rule out other causes. You'll likely be asked to complete some memory, thinking, and pen-and-paper tasks to check how different areas of the brain are functioning, helping the GP decide whether specialist referral is needed.

Specialist Assessment

If a GP is unsure, you may be referred to a specialist — such as an old age psychiatrist, geriatrician, or neurologist — often based in a memory clinic alongside other professionals experienced in dementia care. There's no single, definitive test for Alzheimer's; specialists use cognitive assessments (structured memory and thinking tests covering areas like concentration, language, orientation and visual-spatial skills) alongside listening carefully to concerns raised by you and your family. It's worth knowing that test scores can be influenced by educational background, so they're never used alone to diagnose dementia.

A brain scan — either a CT scan (multiple X-rays combined by computer) or an MRI scan (using magnetic fields and radio waves) — may also be used to rule out other causes and look for signs of Alzheimer's-related changes.

After Diagnosis

Reaching a confirmed diagnosis can take several appointments over months, though sometimes it happens more quickly. It takes time to adjust, for both the person and their family — some find it helpful to seek information and plan ahead straight away, while others need longer to process the news. Talking things through with family, friends, or organisations like the Alzheimer's Society can help, and since Alzheimer's is progressive, the weeks and months after diagnosis are often a sensible time to start thinking about legal, financial and healthcare planning for the future.

Medicines

There's currently no cure, but medicines can temporarily help with symptoms. Acetylcholinesterase inhibitors — donepezil, galantamine and rivastigmine (rivastigmine also available as a patch) — increase acetylcholine levels and are prescribed for early- to mid-stage Alzheimer's, usually continuing into later, severe stages too; they're prescribed by specialists or GPs with particular expertise, with side effects like nausea usually easing after 2 weeks. Memantine works differently, blocking excess glutamate in the brain, and is used for moderate to severe Alzheimer's, particularly for those who can't tolerate the medicines above; temporary side effects can include headaches, dizziness and constipation.

Managing Behavioural Symptoms

In later stages, some people develop behavioural and psychological symptoms — agitation, anxiety, wandering, aggression, delusions or hallucinations — which can be very distressing for everyone involved. If coping strategies aren't enough, a consultant psychiatrist may prescribe risperidone for persistent aggression or extreme distress, used at the lowest effective dose for the shortest time due to potential serious side effects; antidepressants may also help if depression seems to underlie anxiety symptoms.

Non-Medicine Support

Medicine is only one part of dementia care. Cognitive stimulation therapy uses group activities to support memory and problem-solving; cognitive rehabilitation works with an occupational therapist and a relative or friend towards personal goals, using stronger brain functions to support weaker ones; and reminiscence or life story work, using photos, keepsakes or music to explore past experiences, has been shown to improve mood and wellbeing.

Reducing Your Risk

Since the exact cause isn't known, there's no certain way to prevent Alzheimer's, but a healthy lifestyle can help reduce risk or potentially delay onset. Since cardiovascular disease is linked to higher Alzheimer's and vascular dementia risk, steps like stopping smoking, minimising alcohol, eating a balanced diet with at least 5 portions of fruit and vegetables daily, aiming for 150 minutes of moderate exercise weekly, having blood pressure checked regularly, and managing diabetes well can all help. Staying mentally and socially active — reading, learning new skills, volunteering, group activities, and maintaining social connections — is linked with lower dementia rates too, though it's not yet proven that specific "brain training" games prevent dementia, even though they can improve short-term cognitive performance.

Taking Part in Research

Numerous dementia research projects and clinical trials are underway worldwide, including many in the UK. Anyone with a dementia diagnosis, or worried about memory problems, can contribute to research — as can carers, since studies also explore the best ways to support people with dementia. You can sign up via the NHS Join Dementia Research website.