Longitudinal validation of psychosis risk screening tools

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Abstract

The development of widely used interview tools has helped to standardize the criteria for a “clinical high risk” syndrome, thus enabling advances in efforts to develop interventions for this phase of illness. These assessments, however, are burdensome to administer and not likely to be adopted for widespread use. Scalable early intervention depends on the availability of brief, low-cost assessment tools that can serve to screen populations of interest or triage treatment-seekers toward specialized care. The current study examines the sensitivity, specificity, and predictive strength of three self-report measures (Prime Screen—Revised, Prodromal Questionnaire—Brief, and Youth Psychosis at Risk Questionnaire—Brief) with regard to psychosis onset and symptom persistence over six months of follow-up within an indicated sample of 54 adolescents and young adults ages 12–22. Within this sample, all three measures demonstrated excellent sensitivity to emerging psychosis and strong agreement with clinician evaluations of attenuated psychosis symptoms. Additionally, all screeners obtained negative predictive values of 1.00 with regard to psychosis onset, indicating that an individual scoring below the recommended threshold score would be extremely unlikely to develop psychosis over the following six months. The longitudinal validation of psychosis risk screening tools constitutes an important step toward establishing a standard of care for early identification and monitoring in this vulnerable population.

Introduction

Efforts to identify and treat psychosis during the early stages of illness progression have stemmed from research indicating that prompt intervention may maximize treatment effectiveness and quality of life (Fusar-Poli et al., 2013). Research suggesting the relative benefits of a short duration of untreated psychosis (Marshall et al., 2005), as well as findings that many individuals at risk for psychosis can be clinically identified months or years before the onset of schizophrenia or other spectrum disorders (e.g., Cannon et al., 2008), has led to questions regarding the possibility of identifying and treating illness during a pre-psychotic or ‘prodromal’ phase. Effective treatment prior to the emergence of full-blown illness holds potential to delay or even prevent the onset of acute psychosis (Marshall and Rathbone, 2011).

Although psychosis prevention strategies are still emerging, there have been considerable advances in screening/identification of individuals designated as “clinical high risk” (CHR) for psychotic disorders. Interview and self-report measures have been developed to facilitate screening among high-risk populations. In particular, the extensive adoption of structured clinical assessments such as the Structure Interview for Psychosis-risk Syndromes (SIPS) and the Comprehensive Assessment of At-risk Mental States (CAARMS) in programs of CHR research has been useful in that the common criteria are now widely recognized by researchers embarking on related but unique programs of research (Fusar-Poli et al., 2013). Due to high clinician burden associated with training and administration, however, these measures are not well suited for use in generalist mental health settings. The development of brief instruments that can be ‘exported’ for clinical use is a crucial step toward establishing and disseminating evidence-based care for individuals most vulnerable to psychosis.

Brief self-report questionnaires have the potential to screen populations of interest, and may ultimately aid in the detection of far more CHR youth than would be possible through referrals to specialized programs. Research within CHR populations suggests that these patients experience considerable distress as well as impairments in social and occupational functioning well before the onset of full-threshold psychotic symptoms (Addington et al., 2008, Ruhrmann et al., 2008, Velthorst et al., 2010, Cornblatt et al., 2011, Thompson et al., 2015). Screening may be particularly useful for identifying CHR patients at an earlier stage of illness by detecting new-onset symptoms after they have become bothersome to patients, but before they have caused notable impairments.

Screeners may also constitute a useful tool for specialty centers looking to recruit CHR samples for both observational and interventional research. Such programs typically administer the SIPS or CAARMS to determine CHR status and thus eligibility for study participation; conducting many such interviews can be a resource-intensive process. Screening efforts might produce an enriched sample with respect to psychosis risk, thus optimizing assessors' time spent evaluating potentially CHR individuals and limiting time spent on individuals not likely at risk.

A handful of brief self-report measures have been developed with the aim of assessing symptoms putatively indicating a ‘psychosis risk state’ (Addington et al., 2014, Kline and Schiffman, 2014). Given the prospective focus of the CHR concept, longitudinal validation represents a vital step toward understanding how such tools might be appropriately incorporated in clinical and research settings. Although the concurrent agreement of CHR screening tools with clinician assessments has been established, few studies to date have investigated longitudinal outcomes following CHR self-report assessments (Kobayashi et al., 2008, Loewy et al., 2012, Rietdijk et al., 2012). The goal of the current study is to evaluate the predictive validity of three brief CHR self-report questionnaires with regard to symptom progression and psychosis onset over approximately six months within a sample of adolescents and young adults seeking mental health treatment.

Section snippets

Procedures

Procedures were reviewed and approved by the Institutional Review Boards at the University of Maryland (UM) School of Medicine and University of Maryland, Baltimore County (UMBC). After providing informed consent, participants completed the three self-report tools. Those under age 18 gave assent and were required to have a parent or other legal guardian present to provide consent. Screeners were presented in a Latin Square design to enable detection of order effects. Participants were

Results

SIPS diagnoses following T1 and T2 interviews, as well as trajectories for each initial diagnostic group, are described in Table 2. Of those who were initially LR, none transitioned to psychosis. Of the 21 participants meeting the SIPS CHR criteria at T1, 4 (19%) had transitioned to psychosis by T2. Table 3 provides descriptive statistics and sample size for analyses involving each measure. Given that skew and kurtosis were less than or equal to 1.1 for all variables, Pearson correlations were

Discussion

Brief self-report questionnaires have the potential to screen populations of interest, and may ultimately aid in the detection of far more CHR youth than would be possible through clinician- or self-referrals to specialized programs. Prior research also supports the use of screeners as “triage” tools that may be helpful for determining whether youth presenting for mental health services may benefit from more specialized, psychosis-oriented treatment. One of the most comprehensive screening

Role of funding source

This work was supported in part by funding from the Maryland Department of Health and Mental Hygiene, Mental Hygiene Administration through the Center for Excellence on Early Intervention for Serious Mental Illness (OPASS# 14-13717G/M00B4400241). The funders had no influence on study design, analyses, interpretations, or decision to submit manuscript for publication.

Contributors

Dr. Kline oversaw the study design, data analysis, data interpretation, and manuscript preparation. Ms. Thompson and Ms. Demro contributed to the data collected, data analyses, and manuscript preparation. Ms. Bussell oversaw the protocol implementation and contributed to the study design. Drs. Schiffman and Reeves oversaw the protocol development and implementation and contributed to manuscript preparation.

Conflict of interest

The authors have no actual or potential conflicts of interest to report.

Acknowledgment

The authors wish to acknowledge the generous contributions of the study's participants and their families.

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