Schizophrenia, despite intense research in recent decades, remains a bewildering disease. Now U.S.
researchers have used brain imaging to reveal that there is a startling loss of brain tissue in schizophrenics
as the disease progresses.
One in 100 people worldwide has schizophrenia and the success of treatments is still uneven. Drugs that attempt
to redress chemical imbalances in the brain often work well, but a significant number of patients never really
live normal lives.
The symptoms are distressing for loved ones and often incapacitating for the patient. Schizophrenics hear
voices, often persistent and insulting; they can be delusional, fearing for their lives; and their thinking and
speech can be so disordered that they can't communicate.
The cause of schizophrenia, if indeed there is a single cause, is unknown. However, although the overt symptoms
of the disease don't usually appear until patients are in their 20s, there is increasing evidence that some sort
of brain disarrangement has taken place long before that.
Studies of the brains of schizophrenics have revealed that large numbers of brain cells are disorganized or even
misplaced. The arrangement of those cells is established in the middle of fetal life. There even have been
reviews of home movies and videos that seem to suggest that children who go on to become schizophrenic exhibit
subtle movement disorders, like a tic or an odd gait, before they're 10 years old.
Add to this the observation that more schizophrenics are born in late winter and early spring, especially in
cities with cold winters — and the suspicion grows that there might even be some infectious agent, possibly
a virus, that affects fetal brain development in some subtle way that only becomes obvious 20-plus years later.
Finally, genetics play a role: the identical twin of a schizophrenic runs about a 40 per cent chance of being
schizophrenic as well.
To that complex background this new study adds a shocking dimension. The research group mapped the brains of
patients with an unusual form of the disease called very early-onset schizophrenia. These unfortunate children
are already suffering the symptoms of schizophrenia by the time they're 12. The brain scans over a five-year
period, through the patients' early teens, revealed that they suffered a wave of brain tissue destruction,
starting in areas around the middle of the brain, then moving toward the front. The damage is to the so-called
gray matter, the surface of the brain where cells reside.
I haven't seen such a strongly worded scientific report in a long time. The researchers call the progressive
damage a "wave" of destruction; they describe the affected parts of the brain as having been "engulfed" by the
disease process. It is a disturbing picture.
The brain images make some sense of prior findings. Some of the earliest damage appears in those parts of the
brain that control movement; that may relate to the problems seen in the childhood movies. Schizophrenics are
known to have problems with picking out the important elements in a picture, and some of the later damage seen
in these scans occurs in areas responsible for such visual attention.
One of the most intriguing aspects of this research is that the environmental damage can be separated from the
destruction that takes advantage of a genetic susceptibility. The earliest loss is seen in the parietal lobes,
near the top of the brain. Those lobes are thought to be targeted by some unknown environmental factor (perhaps
acting in fetal life).
The evidence for that comes from identical twins. When one gets the disease and the other doesn't, the affected
twin's parietal lobes are damaged. But the cause of that damage must be environmental, because the two
individuals are genetically identical. If genes were all-important, they'd both have the disease.
However, the later destruction in areas toward the front of the brain correlates better to genetics: patients
with similar genetic backgrounds share such loss. With the caveat that these are unusual schizophrenic patients,
the picture emerging from these brain scans is that some early environmental trigger may start the disease
process and an unfortunate genetic predisposition may allow it to progress virtually unchecked.
Jay Ingram hosts the program @discovery.ca on the Discovery Channel.
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