Psychiatr News February 1, 2008
Volume 43, Number 3, page 2
© 2008 American Psychiatric Association
Psychiatrists Gain Tools to Help Predict Conversion to Psychosis
Mark Moran
If an individual meets the SIPS criteria and has one or more of five
predictive symptoms, a clinician should monitor for positive symptoms of
psychosis because that person is at extremely high risk of converting.
Criteria for predicting conversion to psychosis among at-risk individuals
has attained a level of accuracy equal to that of predictive criteria used in
other areas of medicine.
Thirty-five percent of at-risk patients who met criteria according to the
Structured Interview for Prodromal Syndromes (SIPS) converted to psychosis
within two and a half years, according to a report in the January Archives
of General Psychiatry. The study used pooled data on 291 patients at
eight clinical research centers as part of the North American Prodrome
Longitudinal Study.
The predictive power increased up to nearly 80 percent if patients meeting
SIPS criteria also experienced combinations of five predictive symptoms:
genetic risk (having a first-degree relative with psychotic illness), along
with functional decline; unusual thought content; suspicion and paranoia;
decline in social functioning; and any substance abuse.
"If you meet the criteria for SIPS, you have a 35 percent chance of
developing psychosis within 30 months," lead investigator Robert
Heinssen, Ph.D., told Psychiatric News. "With drug abuse, that
risk goes up to about 43 percent, and if you meet the SIPS plus all five
unique predictive factors, it goes up to 79 percent."
He is director of the Schizophrenia Spectrum Disorders Research Program in
the Division of Adult Translational Research at the National Institute of
Mental Health.
"What this means is that we now have clinical indicators that triple
the predictive risk and narrow the window of risk from decades to two and a
half years," Heinssen said. "That really brings the prediction of
psychosis into the realm of real-time clinical decision making."
Heinnsen also emphasized the collaborative nature of the project, pooling
data across eight sites, and the role of the federal government in providing
funding as well as technical support and advice.
Prodrome Called 'Distinct Entity'
Psychiatrist Thomas McGlashan, M.D., a coauthor of the report, said the
findings advance the idea of including the prodrome as a distinct diagnostic
entity in DSM. And he said that prevention of severe mental illness
is now a realizable goal for psychiatry.
"We can now reliably predict who is going to convert to psychosis
using clinical criteria that every psychiatrist can recognize," he said.
"It really means that the prodrome deserves its own category in the
diagnostic manual. And it also means that psychiatrists will have to get
serious about prevention, which is new territory for the profession.
"This is a new perspective for psychiatry," McGlashan said.
In an editorial in the December 2007 Early Intervention in
Psychiatry titled "The DSM Version of Schizophrenia May Be
Harmful to Patients' Health," McGlashan argued that new findings about
early detection and intervention in schizophrenia are rendering the
DSM's current emphasis on functional deterioration and duration of
six months obsolete.
"Delaying the diagnosis of schizophrenia with a long-duration
criterion and a requirement of deterioration may paradoxically foster stigma
and alienation instead of protecting against it," he wrote.
"Allowing unbridled psychosis to exist long enough to be sure of a
diagnosis also allows the person's psychotic behavior and personal
deterioration to identify him or her as 'crazy' by family, friends, school,
work, and community. Delaying diagnosis protects against a false positive
diagnosis and label but at the expense of neglecting or denying a dangerous
clinical situation in the true positive patient—dangerous because of
what can be wrought by the progressive and unchecked paralysis of higher
mental functions."
Combined Factors Increase Risk
In the Archives study, 291 at-risk patients were identified at
baseline as meeting the criteria for the SIPS from the eight participating
centers. They are Emory University; Harvard Medical School; University of
California, Los Angeles; University of California, San Diego; University of
North Carolina, Chapel Hill; University of Toronto; Yale University; and
Zucker Hillside Hospital.
The SIPS criteria for a prodromal syndrome emphasize onset or worsening in
the preceding 12 months of attenuated positive symptoms in one or more of five
possible categories: unusual thought-content, suspicion/paranoia, perceptual
anomalies, grandiosity, and disorganized communication. The instrument is used
to determine whether the patient meets criteria for one or more of three
possible prodromal syndromes: attenuated positive symptom syndrome, genetic
risk and deterioration syndrome, and/or brief intermittent psychosis
syndrome.
At two and a half years, 82 of the at-risk patients converted to psychosis,
representing 35 percent of the cohort that was followed for the entire two and
a half years. (Kaplan Meier Survival analysis, a statistical formula that
adjusts for patients lost to follow-up, was used to ascertain the cumulative
rate of conversion and the incidence rates of conversion within successive
six-month epochs.)
Of the five unique predictive factors, genetic risk with decline in
functioning was the most powerful: a patient who met SIPS criteria and also
had a first-degree relative with schizophrenia and had experienced a decline
in functioning had a 52 percent chance of converting to psychosis, according
to the survey.
The other four unique predictive factors and their associated risks for
conversion when added to the SIPS were unusual thought content (48 percent),
decline in social functioning (46 percent), suspicion and paranoia (43
percent), and any substance abuse (43 percent).
But combinations of those factors raised the risk dramatically. Heinssen
noted also that the SIPS criteria help to demarcate the line between
pre-psychosis and psychosis. "If a person crosses that threshold, then
antipsychotic medication should be initiated," he said. "We know
that the sooner treatment begins after onset, the better the functional
outcome."
He added that the findings now set the stage for neuroimaging and
neurocognitive tests to "identify the mechanisms at the level of the
brain relative to the unfolding over time of this movement from prodrome to
psychosis."
An abstract of "Prediction of Psychosis in Youth at High
Clinical Risk: A Multi-Site Longitudinal Study in North America" is
posted at
<http://archpsyc.ama-assn.org/cgi/content/abstract/65/1/28>.
"The DSM Version of Schizophrenia May Be Harmful
to Patients' Health" is posted at
<www.blackwell-synergy.com/doi/full/10.1111/j.1751-7893.2007.00048.x>.
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