In the U.S. there are 2 million head injuries per year. 80,000 with severe impairment. A million with subtle changes.
NIMH estimates that one half of our population will have a clinical mental illness at some point in our lives
The WHO estimates that over 400 million people suffer from untreated neurobiological disorders.
Delusions and Confabulation Some Thoughts
Serious conditions can cause long-term delusions: Schizophrenia, paranoia, mania, psychosis, severe OCD; or temporary delusional states: acute toxicity, delirium or drug reactions. Dopamine imbalances are often a major factor.
A specific obsessive delusion can be very destructive, as seen in Holocaust Deniers and survivalist Conspiracy Theorists. Temporal lobe epilepsy is also frequently found in delusions of hyper-salience or grandiosity (feelings of being chosen, having a mission, being a spiritual channel, etc.)
Localized brain damage can cause Cotard’s, Capgras and other bizarre conditions.
Deluded people are mostly unable to perceive that they are deluded. Hallucinations (sensory distortions) are also common but do not necessarily impair self-insight.
Delusions can also be based on direct perceptual distortions—As when an anorexic perceives fat on her skeletal frame.
Someone can also have a monothematic or compartmentalized delusion that may not interfere with other intellectual work. HIV denialist Peter Duesberg [who has had a terrible effect on millions of people by convincing African leaders to question the science of HIV/AIDS] is still contributing solid work in cancer research.
Normal people can also have simple “glitches” that lead to blindspots that can appear delusional. And we all tend to confabulate to fill in the blanks.
Brain Damage and Neurological Disabilities Some Thoughts
Reasoning can be compromised by many conditions: HIV infection, Parkinson’s, multiple sclerosis, Huntington’s disease, Korsakoff’s syndrome, Alzheimer’s and many, many more. TBI, stroke and other acquired damage can undermine any aspect of reasoning.
Mild cognitive impairment is often a precursor to dementia or mental decline.
One of the first signs of premorbid dementia is rigid thinking and certainty.
The stereotype of the “set-in-his-ways old codger” is not wholly inaccurate.
Alzheimer’s is now considered a progressive illness that begins decades before serious symptoms emerge. Reagan most likely was already suffering from effects of his disease during his years in office. With his finger on the button, the certainty of his “convictions” might have been even more dangerous than his memory lapses.
Longitudinal studies [see Nun study, Scottish schoolchildren study] found that people who showed high levels of “idea density” in their essays during youth were much less likely to show signs of early dementia. Those with more simplistic and concrete thinking were statistically more likely to get earlier signs of dementia.
The effects of prolonged substance abuse can be devastating: Progressive alcoholism, for example, destroys pathways related to abstract thinking, self-awareness and moral cognition— hence, there appears to be a physical basis for an addict’s denial.
Malnutrition, poverty, exposure to toxins, pesticides and poisons, and other basic deficiencies strip children of their innate mental and developmental capacities, leaving them more vulnerable to political and social manipulation. Lead poisoning is a scourge in poor urban areas in the U.S., and Vitamin A and D deficiencies are leaving swathes of children with compromised learning and thinking, as well as stunted growth.
The rate of retardation in Western nations decreased many-fold when they instituted policies ensuring that all prenatal care included iodine and thiamine supplements.