12 February 2013. A study published February 1 in the American Journal of Psychiatry introduces the final version of the Clinical Assessment Interview for Negative Symptoms (CAINS), a scale that assesses motivation, pleasure, and emotional expression in schizophrenia. The study, led by Ann Kring of the University of California, Berkeley, is the culmination of an iterative, empirical approach undertaken in response to the National Institute of Mental Health’s recognition of the need for an updated measure of negative symptoms for use in treatment trials and basic research.
Although positive symptoms, including hallucinations and delusions, are the most conspicuous schizophrenia symptoms, and typically the ones that bring an individual to clinical attention, negative symptoms produce some of the more debilitating effects of the illness to the detriment of functional outcome. Negative symptoms, so named because they represent a loss of normal function, include several domains: blunted affect (lack of emotional reactivity), asociality (social disengagement), alogia (reduced speech), anhedonia (decreased ability to experience pleasure), and avolition (reduced motivation to pursue goals). Because negative symptoms represent a major roadblock to functional recovery and remain largely untreated with current pharmacotherapy, the development of novel therapies to treat these symptoms is of critical importance.
The need for a better rating scale
Existing negative symptom rating scales, including the Scale for the Assessment of Negative Symptoms (SANS) and the Positive and Negative Symptom Scale (PANSS), are outdated in that they do not reflect more recent constructs, including the distinctions between negative and cognitive symptoms (Blanchard et al., 2011). Other drawbacks include the fact that individual item ratings in the current scales may actually represent multiple distinct negative symptom domains, and a heavy reliance on rater observation of behavior rather than patient reports.
Given these limitations and others, a 2006 National Institute of Mental Health consensus report on negative symptoms identified the development of a new scale for measuring negative symptoms as a top priority to facilitate new treatment development (Kirkpatrick et al., 2006). The Collaboration to Advance Negative Symptom Assessment of Schizophrenia was established and charged with the task of developing and validating a new, data-driven scale—the result of this effort is the CAINS.
Test, revise, repeat
An initial version of the CAINS was developed using over 500 subjects with schizophrenia and schizoaffective disorder. A beta test of this version was conducted on an additional 300 subjects and published in 2011. The results of this first study indicated that the CAINS comprised two factors—“motivation and pleasure for and engagement in social, vocational, and recreational activities” and “emotion expression and speech”—that were moderately correlated (Horan et al., 2011).
The current study assessed an updated version of the CAINS in 162 patients with schizophrenia or schizoaffective disorder who were recruited from outpatient clinics at four different sites. Subjects were assessed twice, an average of two weeks apart. Each session was videotaped and a total of 40 assessments (10 from each site) were independently scored by raters at the other sites to evaluate between-site agreement.
The original two-factor structure broken down into expression and motivation/pleasure subscales was replicated in the current study (Horan et al., 2011). Three of the 16 items on the previous version of the scale were dropped, yielding a final count of 13 items. The authors note that while the CAINS is optimally implemented as a two-scale measure, a composite score of both scales can be easily computed.
The CAINS was stable across the two to three weeks of the study, indicating adequate test-retest reliability, and exhibited strong between-site inter-rater reliability, better than that observed for the SANS (Mueser et al., 1994). Importantly, the scale also demonstrated strong convergent validity—CAINS scores on both subscales were correlated with scores on the SANS and with the negative symptom subscale of the Brief Psychiatric Rating Scale (BPRS), as well as with relevant self-report measures. Discriminatory validity was also achieved, as no significant correlations were observed between the CAINS and depression, medication side effects, IQ, or cognition scales. The CAINS was also linked to functional outcome. The motivation/pleasure scale was related to all domains of functioning assessed, while the expression scale was linked to independent living and family functioning.
Considering the CAINS
The authors note that an important next step will be the inclusion of the CAINS in treatment trials to determine its sensitivity to change. In an accompanying editorial in the same issue of the American Journal of Psychiatry, Deanna Barch of Washington University in St. Louis, Missouri, outlines both the theoretical and practical advantages of the CAINS. A major strength is the use of constructs that are based on three decades' worth of research on affective science and neuroscience, which have the potential to inform both underlying mechanisms as well as potential treatments. For example, the CAINS is the first scale to distinguish between the anticipatory component of pleasure and the experience of it, separate constructs that are now known to depend on different neurotransmitters acting in distinct brain regions (Berridge et al., 2009). In addition, the CAINS provides broader coverage of negative symptoms than the BPRS and PANSS, and is well structured to ensure accurate and consistent use by multiple clinicians and researchers.
Barch also notes that a limitation of the CAINS is its length, which may constrain the ability to incorporate it into practice. Even so, she concludes that the “advances provided by both the theoretical and psychometric development of the CAINS make it an important advance in our field.”—Allison A. Curley.
Kring AM, Gur RE, Blanchard JJ, Horan WP, Reise SP. The clinical assessment interview for negative symptoms (CAINS): Final development and validation. Am J Psychiatry. 2013 Feb 1;170(2):165-72. Abstract
Barch DM. The CAINS: Theoretical and practical advances in the assessment of negative symptoms in schizophrenia. Am J Psychiatry. 2013 Feb 1;170(2):133-5. Abstract