People Born Blind Are Mysteriously Protected From Schizophrenia

Motherboard reports on the possible explanations for why people
born blind are 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?

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Source: *FS – All – Science News 2 Net
People Born Blind Are Mysteriously Protected From Schizophrenia