Age-related mental decline, also known as dementia or Alzheimer’s, is still a mystery to practitioners. Is it lifestyle related, environment related, inherited or mediation related?
Over the next couple of weeks we will be looking at dementia in more depth. We may be living longer and better than ever before. However, by the time we reach our golden years, the chances of us remembering much of our life, past or present, is fading.
The fact is that more people are suffering from some form of age-related mental decline. This chance increases with every decade we live and, according to one team of researchers who have tracked the incidence of the disorder over time, after the age of 60, your risk of developing dementia doubles every five years.
By the time you reach your mid-80s, you face a one in four risk of dementia and by the age of 90, the odds increase to one in three (Alzheimer Dis. Assoc. Disord., 2003). There are so many different terms for this disorder that the prevalence is increased simply by the symptoms being grouped together under one or two headings. Virtually every form of mental decline is classified as dementia.
However, among the elderly, modern medicine must take the greatest blame for mental decline. Despite representing only one-seventh of the population, the over-65s take one-third of all prescription drugs. The average senior takes six drugs at a time, many of which have hugely deleterious effects on the brain.
Evidence is emerging that a large coterie of drugs given for other conditions, such as high cholesterol, depression, inflammation, insomnia, anxiety, heart disease and arthritis, can all bring on dementia – basically, most of the drugs given to us as we grow older.
Many of these drugs cause actual damage to the structure of the brain, including loss of brain volume and the fatty parts of the brain cells. This leads to abnormal tissue accumulation in vital brain regions.
One reason why drugs are so rarely identified as a cause is that researchers cannot agree on whether the features of dementia are the cause or the effect of the disorder. Evidence of the effects of aluminium and mercury on the brain suggest that the physical effects in dementia patients, such as neurofibrillary ‘tangles’, are the result of toxicity rather than a true cause of dementia.
After the age of 60, your risk of developing dementia doubles every five years
In test-tube studies of human brain cells, minute doses of mercury produced changes identical to those of Alzheimer’s disease (J. Neurochem, 2000). Taken together, the results of many studies suggest that toxicity, rather than natural cellular degeneration, is one major cause of dementia.
So what causes dementia?
The prevailing theory of dementia as a disease caused by beta-amyloid plaques in the brain has been challenged by post-mortem evidence.
Some people die mentally fully-functioning. However, with their brains suffused with plaques. Others die with full-blown Alzheimer’s symptoms, but showing no plaques (J. Neurochem, 2009). Therefore, something else, must be involved in Alzheimer’s disease.
Two major theories have been tabled. One is that Alzheimer’s is a kind of diabetes. In fact, 25 years ago, Alzheimer’s patients were found to have abnormal glucose metabolism – a key element of diabetes. Crucially, this abnormality was also found in their brains (J. Neurol, 1988). This ties in with findings that diabetics run more than double the risk of getting Alzheimer’s – even with borderline type 2 diabetes.
Brain imaging and animal studies have now confirmed the diabetes/Alzheimer’s connection, leading some researchers to argue that Alzheimer’s could be classified as ‘fundamentally a metabolic disease’ that contributes to neural cell damage by affecting glucose and insulin in the brain. In fact, experts have even suggested that Alzheimer’s should be termed ‘type 3 diabetes’ (Eur. J. Neuropsychopharmacol., 2014).
So as an all-purpose catchphrase, dementia could be defined as any condition with an observable abnormality involving nerve or glial (non-neuronial) cells. On this basis, there are only four types of true dementia:
• Lewy body dementia – involving movement disorders like those of Parkinson’s disease.
• Vascular dementia – the brain’s blood supply is cut off or interrupted.
• Frontotemporal dementia – usually found in patients under 65, where the frontal or temporal lobes have shrunk.
• Alzheimer’s disease – victims are thought to share three specific abnormalities:
– Senile plaques: abnormal clumps of a type of protein that forms around nerve cells in the grey matter.
– Neurofibrillary tangles: abnormal, twisted bundles of fibres within neurons. These hamper the protein required for healthy neural connections, so messages in the brain are not transmitted correctly.
– Granulovacuolar degeneration: neurons develop ‘holes’, each containing a small, dense protein granule.
Three types of medication have shown to contribute towards dementia. They are anti-depressants, statins, antipsychotic agents and medication for insomnia. Studies have found a greater incidence of dementia among populations using antidepressants.
kathryn@maltanet.net