Alzheimer's Disease and Dementia

What it is

Dementia is not a single disease but a word for a group of conditions in which the brain gradually loses its ability to remember, think, reason and manage everyday life, severely enough to interfere with independent living. Alzheimer's disease is the most common cause, accounting for most cases, but there are others, including vascular dementia, Lewy body dementia and frontotemporal dementia, each with its own pattern, and each covered in its own guide in this chapter.

The decline in dementia is progressive, meaning it worsens over time, and it goes well beyond the occasional forgetfulness of normal ageing. Everyone misplaces keys or forgets a name sometimes; dementia is a steady erosion of memory and thinking that begins to disrupt work, relationships and the basic tasks of daily life. It is a disease of the brain, with physical changes that can be seen and measured, and understanding this is the first step away from the stigma and fear that so often surround it.

What it can look like

Early on, the signs can be subtle and easy to dismiss: forgetting recent conversations or events while older memories stay clear, repeating questions, struggling to find words, losing track of dates, misplacing things in odd places, difficulty with familiar tasks such as handling money, and growing confusion about time or place. Mood and personality can change too, with new anxiety, withdrawal, irritability or low mood.

As it progresses, the person needs more help with daily life, may become disoriented even in familiar surroundings, may not recognise loved ones, and eventually requires full-time care. The course varies between individuals and between the different causes of dementia, but the overall direction is a gradual increase in the need for support. This is hard to read and harder to live, which is exactly why accurate understanding and good support matter so much.

A word about normal ageing, and about stigma

Two myths cause real harm and need naming directly. First, dementia is not a normal or inevitable part of getting old. Many people live into great age with their thinking intact; significant memory loss that disrupts daily life is always worth assessing, never simply accepted as "just old age." Second, in many communities dementia is misunderstood as madness, as bewitchment, as a curse, or as a punishment, and older people with it are sometimes feared, hidden or even accused. This is untrue and cruel. Dementia is a brain disease, no more shameful than diabetes or arthritis, and the person living with it deserves dignity, patience and care.

How common is it

Dementia is common and becoming more so as populations live longer. Tens of millions of people live with it worldwide, with numbers rising fastest in low- and middle-income countries, including across Africa, where awareness, diagnosis and services often lag behind the growing need. Age is the biggest risk factor, with the likelihood rising steeply in later decades, though dementia is not exclusive to the old.

What causes it and what raises the risk

In Alzheimer's disease, specific abnormal proteins build up in the brain over many years, damaging and killing brain cells; the exact triggers are still being researched. Beyond age and a degree of genetic influence, a substantial share of dementia risk is linked to factors that can be influenced across life, and this is a genuinely hopeful area of science. Managing high blood pressure, diabetes and hearing loss, staying physically active and socially connected, not smoking, limiting alcohol, treating depression, and protecting the head from injury all reduce risk. Good control of blood pressure in midlife is among the most important. None of this guarantees prevention, but it meaningfully shifts the odds, and much of it is achievable even where specialist services are scarce.

How it is diagnosed

Diagnosis is made by a doctor through a careful history, ideally including an account from family who have noticed the changes, alongside tests of memory and thinking and a physical examination. A crucial early step is to rule out other, sometimes reversible causes of memory and thinking problems, since several conditions can mimic dementia: depression, thyroid problems, vitamin deficiencies, infections, medication side effects and delirium (see our delirium entry). Blood tests and sometimes brain scans help identify the cause and exclude these mimics. Reaching a diagnosis allows planning, support and treatment of anything reversible, and gives the family understanding in place of fear.

How it is treated and supported

There is no cure yet for Alzheimer's disease, and no treatment that stops or reverses it, though research is active. This honest truth sits alongside a more hopeful one: a great deal can be done to support the person and their family and to improve quality of life at every stage. Some medicines can modestly ease symptoms or slow decline for a period in certain dementias; a specialist decides whether they are appropriate, and they help rather than cure. Treating co-occurring depression, anxiety, pain and sleep problems often improves wellbeing considerably.

The largest part of good dementia care is not medication but support: maintaining routine and a familiar environment, clear and patient communication, meaningful activity, physical health and nutrition, safety in the home, and above all support for the family carers who do most of the caring. Approaches that respond to distress and behaviour changes with understanding rather than sedation are strongly preferred. In African settings, where families and communities carry the bulk of care, practical guidance and support for carers is among the most valuable help available.

Support for families and carers

Caring for someone with dementia is an act of love and also a heavy, often exhausting responsibility that can stretch over years. Carers face grief for the person who is changing, practical strain, and frequently their own depression and burnout, all too often without recognition or help. If you are caring for someone with dementia, your wellbeing matters too, and looking after yourself is not selfish but necessary; you cannot pour from an empty cup. Sharing care among family members, seeking out any local support groups or services, learning practical caregiving skills, and accepting help all make a real difference. Our Get Support page can help you find resources.

Alzheimer's in the African context

In many African communities, the memory loss and confusion of dementia are still seen as a normal part of getting old, or explained as bewitchment, a curse, or madness, so families rarely seek assessment and the condition goes unnamed. Older people are sometimes mistreated, or even accused of witchcraft, because of the very symptoms of their illness. Awareness and diagnostic services are limited, and almost all care falls on families, usually women, without support. Numbers are rising as more people live longer. Recognising dementia as a brain disease, not a normal part of ageing or a spiritual matter, is the first step toward dignity and help, and much can be done to support a person and their family even where no cure exists.