People Born Blind Are Mysteriously Protected From Schizophrenia
Over the past 60-some years, scientists around the world have been writing about this mystery. They've analyzed past studies, combed the wards of psychiatric hospitals, and looked through agencies that treat blind people, trying to find a case. As time goes on, larger data sets have emerged: In 2018, a study led by a researcher named Vera Morgan at the University of Western Australia looked at nearly half a million children born between 1980 and 2001 and strengthened this negative association. Pollak, a psychiatrist and researcher at King's College London, remembered checking in the mental health facility where he works after learning about it; he too was unable to find a single patient with congenital blindness who had schizophrenia. These findings suggest that something about congenital blindness may protect a person from schizophrenia. This is especially surprising, since congenital blindness often results from infections, brain trauma, or genetic mutation -- all factors that are independently associated with greater risk of psychotic disorders.
More strangely, vision loss at other periods of life is associated with higher risks of schizophrenia and psychotic symptoms. Even in healthy people, blocking vision for just a few days can bring about hallucinations. And the connections between vision abnormalities and schizophrenia have become more deeply established in recent years -- visual abnormalities are being found before a person has any psychotic symptoms, sometimes predicting who will develop schizophrenia. But the whispered-about fact persists: Being born blind, and perhaps specific types of congenital blindness, shield from the very disorders vision loss can encourage later in life. A myriad of theories exist as to why -- from the blind brain's neuroplasticity to how vision plays an important role in building our model of the world (and what happens when that process goes wrong). Select researchers believe that the ties between vision and psychotic symptoms indicate there's something new to learn here. Could it be that within this narrowly-defined phenomenon there are clues for what causes schizophrenia, how to predict who will develop it, and potentially how to treat it?
Over the past 60-some years, scientists around the world have been writing about this mystery. They've analyzed past studies, combed the wards of psychiatric hospitals, and looked through agencies that treat blind people, trying to find a case. As time goes on, larger data sets have emerged: In 2018, a study led by a researcher named Vera Morgan at the University of Western Australia looked at nearly half a million children born between 1980 and 2001 and strengthened this negative association. Pollak, a psychiatrist and researcher at King's College London, remembered checking in the mental health facility where he works after learning about it; he too was unable to find a single patient with congenital blindness who had schizophrenia. These findings suggest that something about congenital blindness may protect a person from schizophrenia. This is especially surprising, since congenital blindness often results from infections, brain trauma, or genetic mutation -- all factors that are independently associated with greater risk of psychotic disorders.
More strangely, vision loss at other periods of life is associated with higher risks of schizophrenia and psychotic symptoms. Even in healthy people, blocking vision for just a few days can bring about hallucinations. And the connections between vision abnormalities and schizophrenia have become more deeply established in recent years -- visual abnormalities are being found before a person has any psychotic symptoms, sometimes predicting who will develop schizophrenia. But the whispered-about fact persists: Being born blind, and perhaps specific types of congenital blindness, shield from the very disorders vision loss can encourage later in life. A myriad of theories exist as to why -- from the blind brain's neuroplasticity to how vision plays an important role in building our model of the world (and what happens when that process goes wrong). Select researchers believe that the ties between vision and psychotic symptoms indicate there's something new to learn here. Could it be that within this narrowly-defined phenomenon there are clues for what causes schizophrenia, how to predict who will develop it, and potentially how to treat it?
