Development and psychometric validation of the Clinical Assessment Interview for Negative Symptoms (CAINS)

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Abstract

Progress in the development of new pharmacological and psychosocial treatments for the negative symptoms of schizophrenia is impeded by limitations of available assessment instruments. The multi-site Collaboration to Advance Negative Symptom Assessment in Schizophrenia (CANSAS) was established to develop and validate a new clinical rating scale using a transparent, iterative, and data-driven process. The Clinical Assessment Interview for Negative Symptoms (CAINS) was designed to address limitations of existing measures and assess consensus-based sub-domains, including asociality, avolition, anhedonia, affective blunting, and alogia. The structure and psychometric properties of the CAINS were evaluated in a sample of 281 schizophrenia and schizoaffective outpatients at four sites. Converging structural analyses indicated that the scale was comprised of two moderately correlated factors — one reflecting experiential impairments (diminished motivation and enjoyment of social, vocational, and recreational activities) and one reflecting expressive impairments (diminished non-verbal and verbal communication). Item-level analyses revealed generally good distributional properties, inter-rater agreement, discriminating anchor points, and preliminary convergent and discriminant validity. Results indicate that the CAINS is a promising new measure for quantifying negative symptoms in clinical neuroscience and treatment studies. Results guided item modification or deletion, and the reliability and validity of the revised, shorter version of the CAINS is in the final phase of development within the CANSAS project.

Introduction

Negative symptoms substantially impede functional recovery for people with schizophrenia (Kirkpatrick et al., 2006). Despite their clinical significance, current treatments do not adequately address negative symptoms — there are not yet any medications with a specific indication for negative symptoms and psychosocial interventions show similarly limited benefits (Leucht et al., 1999, Montgomery and Zwieten-Boot, 2006). To address this critical treatment need, the NIMH-Negative Symptom Consensus Development Conference (Kirkpatrick et al., 2006) recommended that the field required a new negative symptoms measure that can be productively used in pharmacological trials. The Collaboration to Advance Negative Symptom Assessment of Schizophrenia (CANSAS) was established to develop and validate a “next-generation” clinical rating scale by following data-driven, iterative, and transparent process (Blanchard et al., 2011). This report describes the psychometric evaluation of a beta version of the Clinical Assessment Interview for Negative Symptoms (CAINS) in a large outpatient sample. This effort is unlike any other scale development project to date in that it includes a large and diverse patient population and adopts a comprehensive empirical approach to item generation, selection, and retention.

The CAINS was designed to address limitations of existing instruments (Horan et al., 2006, Blanchard et al., 2011) and assess the five consensus negative symptom sub-domains (Kirkpatrick et al., 2006). Ratings of asociality, avolition, and anhedonia are based on interviewees' reported subjective experiences of motivation and emotion, as well as frequency of actual engagement in relevant activities. Asociality assesses the degree to which close social bonds are valued and desired, and frequency of social interactions. Avolition assesses level of interest and motivation, and initiation and persistence of behavior. Anhedonia assesses experience and frequency of consummatory pleasure and anticipatory pleasure. The final two domains are rated based on observable behaviors throughout the interview. Blunted affect ratings also include prompts to elicit positive and negative emotions. Ratings for alogia include measures of speech output.

A feasibility study of an early version of the scale (Forbes et al., 2010) demonstrated good internal consistency and inter-rater agreement, and very good convergent and discriminant validity with other symptom and functional outcome measures. However, several areas needed refinement, including skewed and restricted range of anhedonia items, low inter-item correlations in asociality and avolition domains, marginal inter-rater agreement for items in alogia and avolition domains, and difficulties distinguishing among anchor points for several items.

We report here a comprehensive psychometric evaluation of the revised CAINS in a large, diverse sample of outpatients with schizophrenia or schizoaffective disorder based on recommendations that clinically stable patients are preferred for negative symptom treatment development studies (Kirkpatrick et al., 2006, Laughren and Levin, 2006). The first goal was to examine the scale's latent structure through a series of complementary structural analyses. Clarification of the underlying structure of the scale items, which were designed to comprehensively cover five consensus-based content domains, is critical for optimal assessment of the negative symptoms (Blanchard and Cohen, 2006, Blanchard et al., 2011). This was followed by a series of scale development analyses, including analyses of item- and scale-level characteristics, within- and between-site inter-rater agreement, and a preliminary analysis of discriminant and convergent validity. The over-arching goal was to refine the CAINS for use in the final scale development phase of the CANSAS project.

Section snippets

Participants

Participants were 281 people with schizophrenia (n = 223) or schizoaffective disorder (n = 58), ages 18–60, recruited from outpatient clinics at the four CANSAS sites (UCLA, UC-Berkeley, University of Pennsylvania, and the University of Maryland). Patients met diagnostic criteria based on the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID; First et al., 1996). Exclusion criteria were: episode of major depression or mania within the last month; substance dependence in the last six

Sample characteristics

Demographic and clinical information (Table 1) on this chronically ill sample indicate diverse gender and ethnicity, allowing for confidence in applicability to diverse populations. The sample was characterized by generally high levels of functional disability. The majority of participants were unmarried, unemployed, and receiving disability benefits. Clinical symptom ratings on the BPRS and CDSS for this outpatient sample fell in the moderate to low range. Estimated IQ was in the low average

Discussion

The goal of this collaborative project is to develop and validate a state-of-the-art clinical rating scale for negative symptoms so that the next-generation of pharmacological treatments may have more potent and clear treatment targets. Analyses of this large, diverse outpatient sample, which showed considerable functional disability, indicated that the CAINS is a very promising measure for future treatment studies in schizophrenia. Converging structural analyses indicated two underlying

Role of funding sources

This work was supported by the National Institute of Mental Health (K02-MH079231 and R01-MH082839 to JJB; RO1-MH082890 to AMK; R01-MH082782 to WPH; and R01-MH82783 to REG). Funding sources had no role in study design or in the collection, analysis and interpretation of data; or in the writing of this report.

Contributors

Drs. Blanchard, Horan, Kring, and Gur contributed to the study design, data collection, data analysis, interpretation of data analysis, and writing of this report. Dr. Reise contributed to the data analysis, interpretation of data analysis, and writing of this report.

Conflict of interest

None.

Acknowledgments

The authors would like to thank and acknowledge the following people who contributed to the data collection and environment for the study: Janelle Caponigro, Erin Moran, Timothy Campellone, and Ori Ellis at UC Berkeley; Mary March and Elizabeth Hanson at University of Pennsylvania, Medical Center; Shelly Crosby, Heidi Kupppinger, Christen Waldon, Mark McGee, Cory Tripp, Stephen Marder, and Michael F. Green at University of California, Los Angeles; Melanie Bennett, Angie Grodack, and Courtney

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