As shocking as it sounds, no one who was born blind has been a patient of schizophrenia. Tom Pollak, a researcher, and psychiatrist at King’s College London conducted a survey in the mental health department and found the statement to be true. Researcher Vera Morgan’s study at the University of Western Australia in 2018 collected data of half-million kids born between 1980 and 2001 which further strengthened this notion.
The most common causes of congenital blindness include brain trauma, infections, and genetic mutation. These factors are usually associated with psychotic disorders too, but somehow congenitally blind people do not get diagnosed with them. Loss of vision at other phases of life may, however, lead to schizophrenia. If the vision of completely healthy people is blocked for a couple of days, they tend to hallucinate.
There are a bunch of explanations for this strange occurrence. How we perceive the world rests primarily on our vision and if that is hampered at a later stage in life, it leads to psychotic disorders. A research was conducted in 2004 with 13 completely healthy individuals being blindfolded for 4 days straight. During the first two days, ten of them had experienced hallucinations. One of the subjects, a 24 years old man, reported that he could not walk due to the hallucinations that blocked his path. Another subject, a 29 years old woman, saw a strange green face while standing in front of a mirror.
Hallucination does go hand in hand with the loss of vision. This link was first noted in 1760, known as the Charles Bonnet syndrome. Unusual blink rates, issues with the retina, and unusual eye movements raise the probability for a person to become schizophrenic. Schizophrenic people tend to have eyesight issues, if not hallucinations.
In an article published in the journal Schizophrenia Bulletin, Phil and Pollak Corlett, psychology and psychiatry professors at the Yale University, note how the human brain makes predictions about our surroundings. What we see and how we experience what is really happening around us is always juxtaposed with the vision that our mind has of the same things. The comparison leads to changes and updates, following which we have a holistic view of the world around us. This vision works in tandem with other sensory perceptions like touch, sound, and smell according to Polak. For congenitally blind people, there is no gap between what the brain perceives and what really is.
Elaine Walker conducted a study at Emory University in 2006 where she saw the home tapes of schizophrenic people when they were kids. She noticed how the kids were really clumsy and seemed very disoriented, as though there was a gap between their sense of and their interactions with the surroundings. For blind people, the vision of the world is sensory and more stable according to Pollak and Corlett. This stability protects congenitally blind people from any kind of false inference that is common with people diagnosed with schizophrenia. Steve Silverstein, a psychiatrist at the University of Rochester, is of the opinion that being blind makes the brain strong in several ways which leads to a surprisingly high level of functioning. Silverstein adds that people who are at risk of being diagnosed with schizophrenia automatically increase their dependence on non-vision senses.
The connections have given rise to myriad opinions and further studies are being conducted. Congenital lindness is not a safeguard against other illnesses but as of now, there’s no evidence of it leading to schizophrenia.
IMAGE FEATURED: VASILIS VERVERIDIS