Prediction of psychosis in adolescents and young adults at high risk: results from the prospective European prediction of psychosis study.
BACKGROUND
Indicated prevention is currently regarded as the most promising strategy to attenuate, delay, or even avert psychosis. Existing criteria need improvement in terms of specificity and individual risk assessment to allow for better targeted and earlier interventions.


OBJECTIVE
To develop a differential predictive clinical model of transition to first-episode psychosis.


METHODS
Prospective multicenter, naturalistic field study with a total follow-up time of 18 months.


METHODS
Six early-detection outpatient centers in Germany, Finland, the Netherlands, and England.


METHODS
Two hundred forty-five help-seeking patients in a putatively prodromal state of psychosis according to either ultra-high-risk (UHR) criteria or the basic symptom-based criterion cognitive disturbances (COGDIS).


METHODS
Incidence of transition to psychosis.


RESULTS
At 18-month follow-up, the incidence rate for transition to psychosis was 19%. Combining UHR and COGDIS yielded the best sensitivity. A prediction model was developed and included positive symptoms, bizarre thinking, sleep disturbances, a schizotypal disorder, level of functioning in the past year, and years of education. With a positive likelihood ratio of 19.9, an area under the curve of 80.8%, and a positive predictive value of 83.3%, diagnostic accuracy was excellent. A 4-level prognostic index further classifying the general risk of the whole sample predicted instantaneous incidence rates of up to 85% and allowed for an estimation of time to transition.


CONCLUSIONS
The prediction model identified an increased risk of psychosis with appropriate prognostic accuracy in our sample. A 2-step risk assessment is proposed, with UHR and cognitive disturbance criteria serving as first-step criteria for general risk and the prognostic index as a second-step tool for further risk classification of each patient. This strategy will allow clinicians to target preventive measures and will support efforts to unveil the biological and environmental mechanisms underlying progression to psychosis.
Ruhrmann
Stephan
S
Department of Psychiatry and Psychotherapy, University of Cologne, Kerpener Strasse 62, 50924 Cologne, Germany. stephan.ruhrmann@uk-koeln.de
Schultze-Lutter
Frauke
F
Salokangas
Raimo K R
RK
Heinimaa
Markus
M
Linszen
Don
D
Dingemans
Peter
P
Birchwood
Max
M
Patterson
Paul
P
Juckel
Georg
G
Heinz
Andreas
A
Morrison
Anthony
A
Lewis
Shôn
S
von Reventlow
Heinrich Graf
HG
Klosterkötter
Joachim
J
D000328:Adult; D000553:Ambulatory Care; D018450:Disease Progression; D042241:Early Diagnosis; D005060:Europe / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D018570:Risk Assessment; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology; D055815:Young Adult