I have the deepest, most profound respect for Robin Williams. I wish it were more widely known, while he was still living, what a decent, caring, sympathetic person Robin Williams was. I just finished watching the documentary “Robin’s Wish” (available to stream on Plex and Tubi) and learned that the cause of death in the coroner’s report was not “suicide by hanging” but rather “Diffuse Lewy Body dementia.“ Robin Williams was at the mercy of a disease that he could not control and that he did not even know he had. Robin Williams might have taken his own life, or his disease might have taken control of his actions at the end. He knew something was wrong with his brain, and yet brain scans in 2013 and 2014 revealed nothing.

The devastation to Robin Williams’ brain was one of the worst cases medical professionals had ever seen. When I saw words like alpha-synuclein proteinopathy found in the substantia nigra and occipital cortex, insular cortex, temporal cortex; these are the very same protein pathologies and regions of the brain that I describe in my 2026 journal articles. How could they go undetected until his autopsy?

Robin Williams’ Lewy Body Dementia (LBD) went undetected on brain scans in 2013 and 2014 because standard structural imaging (like structural MRIs or CT scans) generally look for visible tumors, strokes, or major atrophy, rather than the microscopic protein deposits that cause LBD.

The specific limitations of medical technology and the nature of the disease at the time included:

Microscopic Pathology: LBD is caused by a microscopic buildup of abnormal proteins, known as Lewy bodies, inside the brain’s nerve cells. These deposits alter brain chemistry and circuitry rather than causing large-scale structural damage. Because the changes are at the cellular level, they are invisible on standard structural scans.

No Diagnostic Biomarker: During his life, there were no specific, widely accepted blood tests, spinal taps, or highly accurate brain-imaging biomarkers available to detect LBD. A definitive diagnosis could only be confirmed post-mortem through a brain autopsy.

Symptom Mimicry: LBD symptoms—which include severe anxiety, paranoia, hallucinations, and sleep disturbances—are widespread and strongly mimic Alzheimer’s disease, Parkinson’s disease, and psychiatric disorders. Williams was initially diagnosed with and treated for Parkinson’s disease, as he suffered from physical symptoms like a shuffling gait and tremors.

Symptom Fluctuation: The cognitive and psychiatric symptoms of LBD can come and go. Because a patient can seem entirely lucid for periods and can “pull themselves together,” medical professionals often misattribute the initial cognitive lapses to stress, fatigue, or depression rather than an irreversible neurodegenerative disease.

Ultimately, pathologists discovered during his autopsy that Williams had one of the most severe and diffuse cases of LBD they had ever seen.