CMHS Consumer Affairs E-News
January 11, Vol. 08-06
NIMH: Scientists Can Predict
Psychotic Illness In Up to 80 Percent of High-Risk
Youth
Youth who are going to develop psychosis can be identified
before their illness becomes full-blown 35 percent of
the time if they meet widely accepted criteria for risk,
but that figure rises to 65 to 80 percent if they have
certain combinations of risk factors, the largest study
of its kind has shown. Knowing what these combinations
are can help scientists predict who is likely to develop
the illnesses within two to three years with the same
accuracy that other kinds of risk factors can predict
major medical diseases, such as diabetes.
Plans for studies to confirm the results, a necessary
step before the findings can be considered for use with
patients in health-care settings, are underway.
The research was conducted in youth with a median age
of 16 and was funded primarily by the National Institute
of Mental Health (NIMH), part of the National Institutes
of Health. Results were published in the January 7,
2008, issue of the "Archives of General Psychiatry" by
lead researchers Tyrone D. Cannon, Ph.D., of the University
of California Los Angeles, and Robert Heinssen, Ph.D.,
of NIMH, with colleagues from seven other research facilities.
The combinations of factors that predicted psychosis
included:
- deteriorating social functioning (for example,
spending increasing amounts of time alone in one's
room, doing nothing);
- a family history of psychosis
combined with recent decline in ability to function
(such as a drop in grades not explained by other factors
or an unexplained withdrawal from extracurricular
school activities).
- increase in unusual thoughts
(such as thinking that strangers'
conversations are about oneself);
- increase in suspicion/paranoia
(such as suspicion of being followed); and
- past
or current drug abuse.
"When teens have a dive in grades or drop out
of the school band, and it happens against a backdrop
of family history of schizophrenia and recent troubling
changes in perception -- like hearing nondistinct buzzing
or crackling sounds, or seeing fleeting images that
disappear with a second glance -- more often than not
it indicates that psychosis is fairly imminent," Cannon
said.
If participants had an unrealistic belief that they
were being followed, for example, but could be shown
that their troubling thoughts were unfounded, the researchers
considered them as having a risk factor, but not yet
psychosis. But if the participants' sense of being followed
became unshakable, despite evidence to the contrary,
or became disabling, the researchers considered them
as having crossed a threshold to psychosis.
Research shows that intervention during the early stages
of psychosis improves outcomes, but it is not yet clear
if even earlier intervention, before a psychotic illness
develops, is effective.
"Having this more accurate ability to measure
who's likely to develop psychosis will be a great asset.
Identifying young people in need of intervention is
crucial, but the results of this research can help us
do more than that. It can eventually help us determine
the most effective time to intervene," said NIMH
Director Thomas R. Insel, M.D.
Researchers from the facilities that conducted the
study used similar criteria and techniques to evaluate
291 high-risk youth, about three times as many as had
been evaluated in any previous study of this kind.
In
addition to being smaller, earlier studies had used
different criteria and measuring techniques from one
another, which clouded the picture and resulted in only
moderate accuracy in predicting psychotic illness.
In this study, a total of 35 percent of participants
with at least one risk factor developed a psychotic
illness within the 30-month study timeframe. However,
when researchers broke the data down further, they found
that the youth who had two or three additional risk
factors developed psychosis at a rate of 68 to 80 percent,
depending on which risk factors were combined.
A separate group of 134 healthy people with no known
risk factors for psychosis served as a control group,
for comparison. None of them developed a psychotic illness.
Researchers also found that the youth who progressed
to a psychotic disorder tended to do so relatively quickly.
Twenty-two percent developed psychosis within the first
year of follow-up, an additional 11 percent by the end
of the second year, and 3 percent more by two-and-a-half
years (adding up to the total percentage of people --
35 percent -- who developed psychosis in this study).
"The message here is that once we identify people
as being high risk, we have a very good chance of knowing
whether or not they're likely to develop a serious mental
disorder like schizophrenia and that, if they do, it
will happen fairly quickly. That's such a critical window
of opportunity for getting them the help they need," said
Heinssen.
The investigators who conducted the study are part
of a consortium of nine research centers, the North
American Prodromal Longitudinal Study (NAPLS), whose
goal is to improve the accuracy of predicting psychosis.
The consortium is funded by NIMH, which also provides
administrative leadership.
In addition to Cannon and Heinssen, NAPLS researchers
who participated in the research included Kristin Cadenhead,
M.D., University of California San Diego; Barbara Cornblatt,
Ph.D., Zucker Hillside Hospital; Scott W. Woods, M.D.,
Yale University; Jean Addington, Ph.D., University of
Toronto; Elaine Walker, Ph.D., Emory University; Larry
J.
Seidman, Ph.D., Harvard Medical School; Diana Perkins,
M.D., University of North Carolina; Ming Tsuang, M.D.,
University of California San Diego; and Thomas McGlashan,
M.D., Yale University.
The Staglin Foundation also provided support for the
research.
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