Validation of the Spanish version of the Clinical Assessment for Negative Symptoms (CAINS)

Abstract

Negative symptoms are a core feature of schizophrenia and their reliable and valid assessment is a prerequisite for developing effective therapeutic interventions. This study examined the psychometric properties and validity of the Spanish version of a new rating instrument, the Clinical Assessment Interview for Negative Symptoms (CAINS). Outpatients and inpatients (N = 100) with DSM-IV schizophrenia were administered the translated CAINS, the Positive and Negative Syndrome Scale (PANSS), the Scale for the Assessment of Negative Symptoms (SANS), and the Calgary Depression Scale for Schizophrenia (CDSS). A subsample (N = 46) was rated for Parkinsonism using the Extrapyramidal Symptoms Rating Scale (ESRS). The scale showed good inter-rater and intra-rater reliability. Both the CAINS overall and the subscales for motivation/pleasure (CAINS-Map) and expression (CAINS-Exp) scores correlated significantly with the SANS and PANSS negative symptom scale. Significant correlations with positive symptoms and general psychopathology were also found, but these reduced and mostly became insignificant when overall severity of illness was controlled for. Significant correlations with depression also disappeared when severity was controlled for. There was a trend-level correlation between the CAINS total score and Parkinsonism, which reflected an association with the CAINS-Exp subscale only. Factor analysis revealed a two-dimensional structure that explained the 67.44% of the variance. Overall, the Spanish version of the CAINS appears to be a valid tool for measuring negative symptoms in schizophrenia.

Introduction

Although delusions, hallucinations, and formal thought disorder tend to be the most arresting aspects of the clinical picture of schizophrenia, negative symptoms, so named because they represent a loss of normal function, are also important (Bernardo and Mezquida, 2014). Thus, they underlie much of the social and occupational disability associated with the disorder (Foussias and Remington, 2010), and they are less responsive to antipsychotic treatment than positive symptoms (Stahl and Buckley, 2007). The development of new therapies for negative symptoms has been identified as a critical aim of schizophrenia research (Kane, 2013, Kirkpatrick et al., 2006, Marder and Kirkpatrick, 2014), and this depends on instruments that can measure them in a reliable, valid, and sensitive way (Blanchard et al., 2011).

The best-known of several available rating scales for negative symptoms is Andreasen's Scale for the Assessment of Negative Symptoms (SANS) (Andreasen, 1982) which went on to achieve very wide usage. Although detailed and rigorous, this scale is now recognized to have limitations. One of these is that as well as rating anhedonia/asociality, avolition, flattening of affect, and alogia, there was also a subscale for attentional impairment, something that at least partly reflects cognitive impairment rather than negative symptoms per se (Blanchard et al., 2011). Another is that the SANS anhedonia/asociality subscale failed to distinguish between anticipatory pleasure and pleasure experienced while engaging in an activity; increasing evidence suggests that only the former is affected in schizophrenia (Barch, 2013, Blanchard et al., 2011). Other scales developed in the years after the SANS face similar criticisms (Alphs et al., 1989, Axelrod and Alphs, 1993, Mortimer et al., 1989), as do negative symptom subscales derived from general symptom scales such as the Positive and Negative Syndrome Scale (PANSS) (Kay et al., 1987, Peralta and Cuesta, 1994) and the Brief Psychiatric Rating Scale (BPRS) (Overall and Gorham, 1962).

In a review of the concept of negative symptoms, the National Institute of Mental Health's (NIMH) Consensus Development Conference on Negative Symptoms (Kirkpatrick et al., 2006) recommended the development of new rating instruments. Since then, two new scales have appeared: the Brief Negative Symptom Scale (BNSS) (Kirkpatrick et al., 2011) and the Clinical Assessment Interview for Negative Symptoms (CAINS) (Kring et al., 2013). The BNSS is a 13-item scale whose stated aim was to be quick and easy to administer (Kirkpatrick et al., 2011), and it has been validated to Spanish by Mané et al. (2014). The CAINS (Horan et al., 2011, Kring et al., 2013), on the other hand, takes the form of a semi-structured interview lasting approximately 30 minutes, which samples the consensus domains of blunted affect, alogia, asociality, anhedonia, and avolition by means of 13 separate items. These items are rated on a five-point (of 0–4) scale, assisted by a user manual and standardized training videos. This scale is made up of two subscales covering ‘motivation/pleasure’ (CAINS-Map, whose items include recreation, social and vocational expected pleasure, and motivation) and ‘expression’ (CAINS-Exp, whose items include vocal prosody, gestures, facial and speech). A psychometric study by Kring et al. (2013) found good internal consistency and test–retest reliability and high inter-rater reliability. Ratings also showed convergent validity with other negative symptoms scales, and there was good discriminant validity with scales measuring other domains of psychopathology, although the CAINs-Map subscale was also found to be modestly correlated with positive symptoms.

The CAINS has so far been translated into Mandarin and Cantonese (Chan et al., 2015) and German (Engel et al., 2014). Given that Spanish is one of the most spoken languages in the world, this study aimed to provide reliability and validity data for clinical and research use in Spanish-speaking populations.