Association of Neurocognition With Transition to Psychosis: Baseline Functioning in the Second Phase of the North American Prodrome Longitudinal Study.
OBJECTIVE
Neurocognition is a central characteristic of schizophrenia and other psychotic disorders. Identifying the pattern and severity of neurocognitive functioning during the "near-psychotic," clinical high-risk (CHR) state of psychosis is necessary to develop accurate risk factors for psychosis and more effective and potentially preventive treatments.


OBJECTIVE
To identify core neurocognitive dysfunctions associated with the CHR phase, measure the ability of neurocognitive tests to predict transition to psychosis, and determine if neurocognitive deficits are robust or explained by potential confounders.


METHODS
In this case-control study across 8 sites, baseline neurocognitive data were collected from January 2009 to April 2013 in the second phase of the North American Prodrome Longitudinal Study (NAPLS 2). The dates of analysis were August 2015 to August 2016. The setting was a consortium of 8 university-based, outpatient programs studying the psychosis prodrome in North America. Participants were 264 healthy controls (HCs) and 689 CHR individuals, aged 12 to 35 years.


METHODS
Neurocognitive associations with transition to psychosis and effects of medication on neurocognition. Nineteen neuropsychological tests and 4 factors derived from factor analysis were used: executive and visuospatial abilities, verbal abilities, attention and working memory abilities, and declarative memory abilities.


RESULTS
This study included 264 HCs (137 male and 127 female) and 689 CHR participants (398 male and 291 female). In the HCs, 145 (54.9%) were white and 119 (45.1%) were not, whereas 397 CHR participants (57.6%) were white and 291 (42.3%) were not. In the HCs, 45 (17%) were of Hispanic origin, whereas 127 CHR participants (18.4%) were of Hispanic origin. The CHR individuals were significantly impaired compared with HCs on attention and working memory abilities and declarative memory abilities. The CHR converters had large deficits in attention and working memory abilities and declarative memory abilities (Cohen d, approximately 0.80) compared with controls and performed significantly worse on these dimensions than nonconverters (Cohen d, 0.28 and 0.48, respectively). These results were not accounted for by general cognitive ability or medications. In Cox proportional hazards regression, time to conversion in those who transitioned to psychosis was significantly predicted by high verbal (premorbid) abilities (β = 0.40; hazard ratio [HR], 1.48; 95% CI, 1.08-2.04; P = .02), impaired declarative memory abilities (β = -0.87; HR, 0.42; 95% CI, 0.31-0.56; P < .001), age (β = -0.10; HR, 0.90; 95% CI, 0.84-0.97; P = .003), site, and a combined score of unusual thought content or delusional ideas and suspiciousness or persecutory ideas items (β = 0.44; HR, 1.56; 95% CI, 1.36-1.78; P < .001).


CONCLUSIONS
Neurocognitive impairment, especially in attention and working memory abilities and declarative memory abilities, is a robust characteristic of CHR participants, especially those who later develop psychosis. Interventions targeting the enhancement of neurocognitive functioning are warranted in this population.
Department of Psychiatry, Harvard Medical School at Beth Israel Deaconess Medical Center, Boston, Massachusetts2Department of Psychiatry, Harvard Medical School at Massachusetts General Hospital, Boston.
Larry J
LJ
Seidman
Department of Psychiatry, Harvard Medical School at Beth Israel Deaconess Medical Center, Boston, Massachusetts.
Daniel I
DI
Shapiro
Department of Psychiatry, Harvard Medical School at Beth Israel Deaconess Medical Center, Boston, Massachusetts.
William S
WS
Stone
Department of Psychiatry, Harvard Medical School at Beth Israel Deaconess Medical Center, Boston, Massachusetts.
Kristen A
KA
Woodberry
Department of Psychiatry, Harvard Medical School at Beth Israel Deaconess Medical Center, Boston, Massachusetts.
Ashley
A
Ronzio
Department of Psychiatry, Zucker Hillside Hospital, Queens, New York.
Barbara A
BA
Cornblatt
Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada.
Jean
J
Addington
Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles6Department of Psychology, University of California, Los Angeles.
Carrie E
CE
Bearden
Department of Psychiatry, University of California, San Diego.
Kristin S
KS
Cadenhead
Department of Psychology, Yale University, New Haven, Connecticut9Department of Psychiatry, Yale University, New Haven, Connecticut.
Tyrone D
TD
Cannon
Department of Psychiatry, University of California, San Francisco11San Francisco Veterans Affairs Medical Center, San Francisco, California.
Daniel H
DH
Mathalon
Department of Psychiatry, Yale University, New Haven, Connecticut.
Thomas H
TH
McGlashan
Department of Psychiatry, The University of North Carolina at Chapel Hill.
Diana O
DO
Perkins
Department of Psychiatry, University of California, San Diego.
Ming T
MT
Tsuang
Department of Psychology, Emory University, Atlanta, Georgia14Department of Psychiatry, Emory University, Atlanta, Georgia.
Elaine F
EF
Walker
Department of Psychiatry, Yale University, New Haven, Connecticut.
Scott W
SW
Woods
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D019965:Neurocognitive Disorders / Q000175:diagnosis* / Q000523:psychology*; D009483:Neuropsychological Tests; D009656:North America; D011237:Predictive Value of Tests; D062706:Prodromal Symptoms; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000523:psychology*; D012016:Reference Values; D012306:Risk; D055815:Young Adult