http://www.nih.gov/news/pr/
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.
For more information about schizophrenia, visit the NIMH web site at
http://www.nimh.nih.gov/
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