|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
The combinations of factors that predicted psychosis included:
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
- increase in
unusual thoughts (such as thinking that strangers' conversations
are about oneself);
in suspicion/paranoia (such as suspicion of being followed);
- 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
The National Institute of Mental Health (NIMH) mission is to reduce
the burden of mental and behavioral disorders through research
on mind, brain, and behavior. More information is available at
the NIMH website: http://www.nimh.nih.gov/.
The National Institutes of Health (NIH) — The Nation's
Medical Research Agency — includes 27 Institutes and
Centers and is a component of the U.S. Department of Health and
Human Services. It is the primary federal agency for conducting
and supporting basic, clinical and translational medical research,
and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and
its programs, visit www.nih.gov.
Cannon TD, Cadenhead K, Cornblatt B, Woods SW, Addington J, Walker
E, Seidman LJ, Perkins D, Tsuang M, McGlashan T, Heinssen R. Prediction
of Psychosis in High Risk Youth: A Multi-Site Longitudinal
Study in North America. Archives of General Psychiatry. January