Psychosis risk screening in youth: A validation study of three self-report measures of attenuated psychosis symptoms

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Abstract

Brief self-report questionnaires that assess attenuated psychosis symptoms have the potential to quickly and effectively screen many people who may benefit from clinical monitoring or early intervention. The current study sought to examine and compare the criterion validities of attenuated symptoms screening tools with diagnoses obtained from the clinician-administered Structured Interview for Psychosis Risk Syndromes (SIPS). Three screening questionnaires (Prime Screen, Prodromal Questionnaire-Brief, and Youth Psychosis At-Risk Questionnaire-Brief) were administered just prior to the SIPS interview in a sample of adolescents and young adults seeking mental health services. Using thresholds recommended by instrument authors as well as empirically derived optimal thresholds, the sensitivity, specificity, positive predictive value, and overall accuracy of each self-report measure with regard to SIPS diagnosis were obtained. Screeners correlated highly with the SIPS and demonstrated equivalent overall efficiency in capturing psychosis risk status. All three screeners appear to be useful and valid assessment tools for attenuated symptoms, with each instrument demonstrating relative benefits. The validation of attenuated symptoms screening tools is an important step toward enabling early, wide-reaching identification of individuals on a course toward psychotic illness.

Introduction

Despite advances in identification and treatment, schizophrenia and other psychoses continue to have a devastating impact. The average age of onset appears to be early adulthood, with most individuals on a trajectory toward psychosis experiencing some symptoms during adolescence (Cornblatt et al., 2009). A substantial body of research indicates that early intervention is associated with better treatment response, whereas a longer duration of untreated psychosis predicts poorer outcomes for those struggling with psychotic illness (Marshall et al., 2005). The association between duration of untreated psychosis and illness course highlights the need for advances in early identification.

Structured interviews for evaluating psychosis risk such as the Structured Interview for Psychosis Risk Syndromes (SIPS; Miller et al., 1999, Miller et al., 2003) and the Comprehensive Assessment of At-Risk Mental States (CAARMS; Yung et al., 2005) have contributed substantially toward creating a reliable and valid system for identifying risk prior to psychosis onset. These assessments evaluate psychosis risk largely through the identification of attenuated positive symptoms, sometimes referred to as the “At-Risk Mental State” (ARMS) or the “Attenuated Psychosis Syndrome” (APS). Programs of high-risk identification have been replicated by independent groups, yielding rates of prediction accuracy ranging from 16 to 52% with regard to psychosis onset within two years of meeting ultra-high risk criteria (Cannon et al., 2008, Yung et al., 2008, Correll et al., 2010, Ruhrmann et al., 2010). Despite some successes with high-risk identification, APS-based paradigms require further refinement before they can be responsibly incorporated in community settings (Fusar-Poli and Yung, 2012).

The ability to identify high-risk individuals through low-cost, brief, reliable methods is essential to the success of efforts to refine the APS construct. Clinician-administered interviews such as the SIPS require specialized training and are too labor-intensive to be used for screening or brief assessment purposes. Additionally, the positive predictive values obtained through interview-based assessments have been variable (Correll et al., 2010). The expanded use of screening tools might serve to address some of these concerns. Brief assessments capable of identifying individuals with APS may provide a methodological advantage with respect to recruiting samples high in the construct of interest. Increased outreach to potentially vulnerable populations through clinical screening can potentially yield more accurate and comprehensive detection of individuals on a progression toward psychosis.

Researchers have developed several self-report instruments targeting APS. These screeners have received varying amounts of validation, with each measure showing strong convergence with clinician interviews in independent samples (Miller et al., 2004, Ord et al., 2004, Kobayashi et al., 2008, Loewy et al., 2011, Jarrett et al., 2012). As validation samples may vary with regard to clinical and demographic characteristics, it is difficult to directly compare these measures' relative agreement with interview-based risk status. A study examining the convergence of several measures in the same sample suggested that APS screening tools demonstrate acceptable convergent and discriminant validity with one another relative to measures targeting different constructs (Kline et al., 2012). This study did not, however, incorporate a clinician-based interview. No study to date has examined the relations between several simultaneously-administered screening measures and interview-based APS status in an effort to determine which measure relates most strongly to a “gold-standard.” Such work might provide clues as to which screener has the most real-world clinical utility.

The aim of the current study is to explore the relative validity of three APS screening questionnaires by determining the accuracy of each screener with regard to SIPS diagnosis in a clinical sample. Three brief self-report instruments (Prodromal Questionnaire-Brief, Loewy et al., 2011; Youth Psychosis At-Risk Questionnaire, Ord et al., 2004; Prime Screen, Miller et al., 2004) were administered prior to the SIPS in a sample of youth receiving mental health services in order to determine the level of agreement between self-report responses and clinician ratings on each of the three screeners.

Section snippets

Procedures

All procedures received Institutional Review Board approval at the University of Maryland, School of Medicine and University of Maryland, Baltimore County. After providing informed consent (for minors, assent), participants completed the three APS self-report tools. Screeners were presented in a Latin Square design (i.e., the order of the three screening tools varied such that participants were randomly assigned to complete each measure either first, second, or third) to enable detection of

Descriptive statistics

All continuously-scored measures demonstrated reasonable normality (Curran et al., 1996).2 To detect possible order effects,

Discussion

The primary aim of the study was to evaluate the relative agreement of three APS screening instruments with the SIPS by administering measures concurrently within a sample of youth seeking mental health services. As continuous measures of APS, all three screeners correlated highly with the interview-based criterion. As dichotomous predictors of SIPS-diagnosed psychosis risk status, their performance was acceptable, although somewhat hampered by a high rate of false-positives and lower than

Role of the funding source

This work was supported in part by a Research Seed Funding Initiative (RSFI) grant from University of Maryland, Baltimore County, and by the Division of Child and Adolescent Psychiatry within the University of Maryland.

Contributors

Emily Kline and Gloria Reeves contributed to study design and data analysis. Camille Wilson, Sabrina Ereshefsky, Danielle Denenny, Elizabeth Thompson, and Kristin Bussell oversaw protocol implementation and data management. Steven Pitts assisted in the design of the study and served as a statistical consultant. Jason Schiffman was Principal Investigator for this project and assisted with all stages of design, implementation, analysis, writing, and editing. All authors contributed to and have

Conflict of interest

The authors do not have any actual or potential conflicts of interest to report.

Acknowledgments

None.

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