Mind Altering Diseases

The brain is both essential and surprisingly fragile.

Basically, your brain defines who you are. When there are physical changes to the brain that change what you know and how you think, functionally you become a different person. It may look like the same you on the outside, but it’s not.

There is a class of diseases that can cause:

  • Loss of memory including inability to recognize people and places
  • Depression
  • Mood swings
  • Fear and paranoia
  • Abrupt changes in behavior, including suicide

This is not the zombie of science fiction, video games or right wing fantasies. The patient is still able to think and retain some control over actions, at least for awhile. With some of these diseases, the disease is progressive leading to death. With others, some recover is possible. However, holding a job or living independently may not be possible. Some will need care, for how long we don’t know.

These diseases include:

  1. Alzheimer’s: Probably the most known disease, plaque build-up from inflammation in the brain chokes connections between neurons and causes brain cell death. Eventually the brain shrinks and dies, taking the person along. During the progression of the disease, patients will lose the inability to recognize friends and loved ones and places and often become violent.
  2. Vascular dementia: Quite similar to Alzheimer’s and often confused with it, this disease results from oxygen deprivation to the brain which also causes cell death. Often the root cause is an undiagnosed heart or lung issue, resulting in low oxygen levels in the blood stream. The progression of this disease is similar to Alzheimer’s as well.
  3. Parkinson’s: This disease reduces levels of two neurotransmitters, dopamine (affecting movement including speech) and serotonin (affecting mood and sleep). These changes can drive patients into isolation and depression.
  4. Huntington’s: This disease breaks down neurons in one region of the brain, causing the patient to lose inhibitions and become more impulsive. The suicide rate among Huntington’s patients is 10 times greater than the national average.
  5. Multiple sclerosis: Can cause mood swings and loss of touch with reality.
  6. Sexually Transmitted Diseases, e.g., syphilis
  7. Brain tumors, especially in the frontal cortex: The frontal cortex contains the areas that handle personality, problem-solving and memory. Any intrusion can disrupt those functions.
  8. Thyroid disease: Any changes in hormones governed by the thyroid gland can cause irritability and large mood swings. That’s a particular issue with diabetics.
  9. HIV: Swelling of the brain induces paranoia and hallucinations as well as issues with memory and concentration.
  10. Lyme Disease: These problems occur at an advanced stage of this disease. With prompt identification and treatment, most patients don’t get there.
  11. Traumatic brain injury (TBI): We all should know about the issue with football players including both suicide and criminal activity that are attributable to brain injuries. However, concussions in American football affect players in college and high school. They also affect people involved in other sports, in certain occupations including the military and public safety, and who have endured serious accidents (auto or falls, for example). TBIs reduce reaction time and the ability to process information as well as producing mood swings.
  12. Covid-19: Yep, that Covid-19.

“People arrived at the hospital with severe depression, hallucinations, or paranoia—and then we diagnosed them with COVID.”

Maura Boldrini, a neuroscientist and psychiatrist at Manhattan’s Columbia University Irving Medical Center (1)

The common element in a lot of these diseases is sustained inflammation. This can trigger an excessive immune system response that releases substances that actually are toxic to neurons. Neurons are what move electrical signals through the brain that allow us to retain information, think and move.

Recent studies in the US and UK have identified the following impacts of Covid-19:

  • Loss of neurons in the hippocampus region of the brain, the area responsible for learning and memory — 90% fewer new neurons than are found normally in an adult. This may be the cause of the brain fog associated with Long Covid.
  • Reduced levels of serotonin.
  • Thinning of the cortex.
  • Loss of gray matter.

Sustained inflammation and especially Cytokine Storms are hallmarks of Covid-19.(7) This is presumably what happens when a child dies of multiple organ failure, the condition known as MIS-C.

However, Covid can do more.

Scientists have now confirmed that the SARS-CoV-2 virus can penetrate, reproduce inside, and kill certain brain cells. The most vulnerable brain cells are astrocytes, which exist in the brain and spinal cord, regulating communications between neurons and maintaining the barrier between the brain and the rest of the body.

Astrocytes, found online

The metaphor is “kill the guards and go where you will.”

This is where things get dicey for the future. Brain damage can occur with people who never displayed symptoms of Covid. At present, we don’t know

  1. The incidence or extent of damage in the population.
  2. How long it may take for damage to become evident, and whether it will increase with time.
  3. How people are going to cope with damage.
  4. How we are going to pay for the care of these people.
  5. How companies and the economy will cope if we have a permanently smaller labor force and consumer base. Right now, companies and the stock market demand continual growth, and that may not be possible.

For now, you need to save money as best you can. If you live in the US, you should consider investing in Long Term Care or Disability insurance while they remain available at a reasonable cost. Policy changes and price increases are inevitable and have already started.

Finally, this post started with reporting by Sharon Guynup in National Geographic. I’ve mentioned before that National Geographic has become a valuable resource for reliable and unbiased information. While I can nitpick this article, overall it represents excellent reporting — the kind of detailed work that we used to find in newspapers prior to the Internet Age. This piece finally pushed me into becoming a subscriber.

(And no, there is no compensation for this endorsement. I don’t do that. If I say I like something, I say it because it’s true.)


  1. https://www.nationalgeographic.com/science/article/can-covid-19-alter-your-personality-heres-what-brain-research-shows?cmpid=org=ngp::mc=crm-email::src=ngp::cmp=editorial::add=SpecialEdition_20220211::rid=40F6968D95F9BCBACD72ADD9433713F9
  2. https://www.advancednh.com/2018/07/29/diseases-change-personality/
  3. https://www.sciencedirect.com/science/article/abs/pii/S088915910800041X?via%3Dihub
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2464619/
  5. https://pubmed.ncbi.nlm.nih.gov/20012068/
  6. https://www.sciencedirect.com/topics/neuroscience/astrocyte
  7. https://blog.dana-farber.org/insight/2021/07/what-is-a-cytokine-storm/


  1. Mr Crain, once again you have touched on a topic that is immeasurable in the importance it brings forth to average readers like me. Understanding the impact of inflammation, as you point out in your prior post, and now these very serious diseases is essential and each of us need to take stock and change what we can – for long-term well being. Thank you.

    Liked by 1 person

    • That is very high praise, thank you very much. You are hardly an average reader.
      I picked up on this because it is valuable information and provides a context that seems to be lacking, especially among politicians.
      Feel free to edit, add or make use of it as you wish. The more people who see this information, the better.


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