The Motivation and Pleasure Scale–Self-Report (MAP-SR): Reliability and validity of a self-report measure of negative symptoms

Abstract

The Clinical Assessment Interview for Negative Symptoms (CAINS) is an empirically developed interview measure of negative symptoms. Building on prior work, this study examined the reliability and validity of a self-report measure based on the CAINS—the Motivation and Pleasure Scale–Self-Report (MAP-SR)—that assesses the motivation and pleasure domain of negative symptoms. Thirty-seven participants with schizophrenia or schizoaffective disorder completed the 18-item MAP-SR, the CAINS, and other measures of functional outcome. Item analyses revealed three items that performed poorly. The revised 15-item MAP-SR demonstrated good internal consistency and convergent validity with the clinician-rated Motivation and Pleasure scale of the CAINS, as well as good discriminant validity, with little association with psychotic symptoms or depression/anxiety. MAP-SR scores were related to social anhedonia, social closeness, and clinician-rated social functioning. The MAP-SR is a promising self-report measure of severity of negative symptoms.

Introduction

Negative symptoms of schizophrenia are associated with poor functional outcome and are only minimally responsive to antipsychotic medication. Research has shown that approximately 28% to 36% of individuals with schizophrenia show elevated negative symptoms [1], and they demonstrate worse social and community functioning compared to those with schizophrenia with lower levels of negative symptoms [1]. Such findings illustrate the critical importance of sound assessment of negative symptoms. The Clinical Assessment Interview for Negative Symptoms (CAINS) [2], [3], [4] was developed to address the limitations of existing measures of negative symptoms [2], [4], [5], [6], [7] by going beyond indicators of behavioral success (e.g., functional outcome). The CAINS offers unique contributions to assessment with its emphasis on individuals' internal experiences of motivation, drive, and interest; inclusion of clear descriptive anchor points; and provision of a comprehensive user's manual and training videos [2], [8]. Additionally, the CAINS has good convergent and discriminant validity and inter-rater reliability [8], [9] across its two factor-derived scales measuring deficits in motivation and pleasure (MAP) and expression (EXP).

There are many cases in which time precludes the use of an extended interview for the assessment of negative symptoms. A self-report measure would provide a time efficient method for the initial identification of people with elevated negative symptoms [10]. To this end, we sought to evaluate a self-report version of the CAINS. The two-factor structure of negative symptoms informed development, where one factor reflects deficits in motivation and pleasure (anhedonia, asociality, amotivation) and the other reflects expressive deficits (blunted affect andalogia). This factor structure has been identified in various clinical interviews [11], [12], [13] and has been replicated in recent studies of the CAINS [8], [9]. In a preliminary study, Park and colleagues [14] administered the CAINS-SR to 69 people with schizophrenia or schizoaffective disorder. The Experience Subscale (e.g., motivation, pleasure, asociality) showed good internal consistency, good convergent validity with the Experience domain of the CAINS, and good discriminant validity. The internal consistency and validity of the Expression subscale were less robust.

These findings led to further refinement of the self-report measure of negative symptoms. Due to poor reliability and validity, the Expression items were removed, yielding a revised measure that focuses exclusively on self-reported deficits in motivation and pleasure. Given this new focus, the measure was renamed the Motivation and Pleasure Scale–Self-Report (MAP-SR). Sharpening the focus of the measure should improve its utility as a self-report measure of negative symptoms since motivation and pleasure capture many of the core deficits of negative symptoms that are directly related to functional impairment [2].

The current study evaluated the psychometric properties of the MAP-SR in a sample of outpatients with schizophrenia and schizoaffective disorder. We examined internal consistency, convergent validity with the CAINS interview, and discriminant validity. We hypothesized that the MAP-SR would demonstrate (1) good internal consistency, (2) a significant positive correlation with the Motivation and Pleasure (MAP) scale of the clinician-rated CAINS, and (3) no significant correlations with clinician-rated depressive or psychotic symptoms. We also explored the relationship between the MAP-SR and other trait and functioning measures, including associations between the MAP-SR, self-reported traits of social anhedonia and social closeness, and clinician-rated functional capacity and community functioning. We also examined whether MAP-SR scores were related to gender and general cognitive ability.