title: The WERCAP Screen and the WERC Stress Screen: psychometrics of self-rated instruments for assessing bipolar and psychotic disorder risk and perceived stress burden.
abstract: BACKGROUND
  Identification of individuals in the prodromal phase of bipolar disorder and schizophrenia facilitates early intervention and promises an improved prognosis. There are no current assessment tools for clinical risk symptoms of bipolar disorder, and psychosis-risk assessment generally involves semi-structured interviews, which are time consuming and rater dependent. We present psychometric data on two novel quantitative questionnaires: the Washington Early Recognition Center Affectivity and Psychosis (WERCAP) Screen for assessing bipolar and psychotic disorder risk traits, and the accompanying WERC Stress Screen for assessing individual and total psychosocial stressor severities.
  
  
  METHODS
  Prevalence rates of the WERCAP Screen were evaluated among 171 community youth (aged 13-24 years); internal consistency was assessed and k-means cluster analysis was used to identify symptom groups. In 33 participants, test-retest reliability coefficients were assessed, and ROC curve analysis was used to determine the validity of the psychosis section of the WERCAP Screen (pWERCAP) against the Structured Interview of Psychosis-Risk Symptoms (SIPS). Correlations of the pWERCAP, the affectivity section of the WERCAP Screen (aWERCAP) and the WERC Stress Screen were examined to determine the relatedness of scores with cognition and clinical measures.
  
  
  RESULTS
  Cluster analysis identified three groups of participants: a normative (47%), a psychosis-affectivity (18%) and an affectivity only (35%) group. Internal consistency of the aWERCAP and pWERCAP resulted in alphas of 0.87 and 0.92, and test-retest reliabilities resulted in intraclass correlation coefficients of 0.76 and 0.86 respectively. ROC curve analysis showed the optimal cut-point on the pWERCAP as a score of >30 (sensitivity: 0.89; specificity: 1.0). There was a significant negative correlation between aWERCAP scores and total cognition (R=-0.42), and between pWERCAP scores and sensorimotor processing speed. Total stress scores correlated significantly with scores on the aWERCAP (R=0.88), pWERCAP (R=0.62) and total cognition (R=-0.44).
  
  
  CONCLUSIONS
  Our results show that the WERCAP Screen and the WERC Stress Screen are easy to administer and derived scores are related to cognitive and clinical traits. This suggests that their use could have particular benefits for epidemiologic studies and in busy clinical settings. Longitudinal studies would be required to evaluate clinical outcomes with high questionnaire scores.
authors.affiliation: Department of Psychiatry, Washington University, St. Louis, Missouri. Electronic address: mamahd@psychiatry.wustl.edu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mamah
authors.affiliation: Department of Psychiatry, Washington University, St. Louis, Missouri.
authors.forename: Akinkunle
authors.initials: A
authors.lastname: Owoso
authors.affiliation: Department of Psychology, Washington University, St. Louis, Missouri.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Sheffield
authors.affiliation: Department of Psychiatry, Washington University, St. Louis, Missouri.
authors.forename: Chelsea
authors.initials: C
authors.lastname: Bayer
mesh_terms: D000293:Adolescent; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000453:epidemiology; D017281:Cost of Illness; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D062706:Prodromal Symptoms; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000453:epidemiology; D021641:Recognition, Psychology; D015203:Reproducibility of Results; D012307:Risk Factors; D057566:Self Report; D012680:Sensitivity and Specificity; D013315:Stress, Psychological / Q000175:diagnosis* / Q000453:epidemiology; D014861:Washington / Q000453:epidemiology; D055815:Young Adult