As every other unruly or spirited child is today labelled as having 'ADHD' (attention-deficit/hyperactive disorder), so many older people who start to lose their mental acuity are diagnosed as having Alzheimer's disease (AD). But, like ADHD, AD is among the most misdiagnosed conditions. Even back in 1981, when Alzheimer's had yet to reach its current status as 'the most common form of dementia', according to experts, more than half of all AD cases were later found at autopsy not to have been (Lancet, 1981; i: 824-7).
What is Alzheimer's?
AD is a specific brain disorder that affects thinking, memory and language. It was named after German doctor Alois Alzheimer who, in 1906, noticed various changes in the brain of a female patient, including abnormal clumps - now called 'amyloid plaques' - and tangled bundles of fibres (neurofibrillary tangles). A doctor can only know for sure if you have the condition after death, when an autopsy can be performed.
Until then, specialists have to assume that you have AD on the basis of your behaviour and mental decline.
What doctors tell you
Most doctors believe that AD and dementia are caused by 'ageing' as the number of people diagnosed with the disease doubles every five years beyond age 65 years.
Apart from this nebulous explanation, specialists believe that family history, or genetics, may also play a part. Yet, even this theory flies in the face of the facts. Familial AD is, as the name suggests, inherited, and usually occurs between the ages of 30 and 60, but it's an extremely rare form of the disease. No pattern of inheritance has ever been identified with the most common, late-onset, form, which develops as you get older.
None of the drugs prescribed for it works very well, and none works at all when AD is in its later stages. Aricept (donepezil) has been the drug of choice, but a recent long-term study revealed that it neither slows the progress of the disease nor delays the time when the patient has to be taken into care (Lancet, 2004; 363: 2105-15).
HRT (hormone-replacement therapy) has also been given to women with mild-to-moderate AD, and has improved mental function and controlled moods in several trials (Neurology, 2001; 57: 605-12; Psychoneuroendocrinology, 1999; 24: 657-77). But a later analysis found that the study of just 12 women was too small and that other factors may have influenced the results (Arch Neurol, 2003; 60: 209-12).
Some doctors also prescribe NSAIDs (non-steroidal anti-inflammatory drugs) to reduce inflammation in the brain - but, again, there is no evidence that this is beneficial.
What causes it?
There are as many theories of the cause of AD as there are misdiagnoses. It's been linked to metal poisoning, mainly from the aluminium in cookware or mercury from tooth fillings, or a deficiency in essential nutrients such as vitamins B6 and B12, folic acid, thiamine or nicotinic acid. Indeed, trials of these supplements have had moderate success. But it could also be a result of poor circulation to the brain or hardening of brain arteries, pernicious anaemia or a reaction to certain drugs.