By Amy Norton
NEW YORK, Jun 19 (Reuters Health) - Men who develop schizophrenia before age
19 show more profound defects in brain functioning than those who have a later
onset, researchers report. The finding, the investigators suggest, could provide
a way to measure how well antipsychotic drugs work in these men.
A brain disorder marked by profound disturbances in thinking, perception and
behavior, schizophrenia has complex roots and affects people with varying
severity. Men are more likely than women to develop symptoms in their teens, and
younger onset typically means more severe symptoms.
Now researchers report that younger onset is strongly related to problems in
an important measure of brain function. These men seem particularly unable to
"filter out" the stimuli that bombard all people, everyday. Dr. Tonmoy Sharma
and his colleagues at the University of London report their findings in the June
issue of the Archives of General Psychiatry.
Sharma's team looked at "startle responses" in 38 men with schizophrenia and
20 healthy men. A real-world equivalent would be a person's reaction to a car
backfiring or some other jarring noise. Sharma and his colleagues specifically
examined the effects of exposing subjects to a weaker "prepulse" before they
were hit with the startling stimulus--for instance, the sounds of traffic before
the car backfires.
Normally, such prepulses reduce the impact of any intense stimulants that
follow. Sharma told Reuters Health that our normal ability to filter out stimuli
and process only certain information is "what allows us to survive." In
schizophrenics, he said, this ability breaks down.
In fact, his team found that when subjects listened to noises through
headphones, it was only those with early-onset schizophrenia who showed poor
ability to filter out stimuli. According to Sharma, this is the first time that
the age of schizophrenia onset has been linked to this disrupted brain function.
Even those on newer types of antipsychotic drugs did not show normal
functioning.
Newer drugs, Sharma noted, have been shown to be more effective in
schizophrenics whose symptoms come on in adulthood. Tests of information
processing like the one in this study, he said, could be used to gauge whether
drugs are helping patients.
Moreover, the ability to categorize schizophrenia into distinct groups could
help researchers pinpoint the genes that predispose people to the illness.
Another feature of early-onset schizophrenia, Sharma noted, is that it is more
likely to run in families.
