Psychometric evaluation of a brief self-report measure and of EMA items assessing the suicide crisis syndrome: Insights on reliability, validity and temporal variability

• The SCS can be reliably and repeatedly assessed. • Links between SCS scores and psychopathological variables support convergent validity. • Fine-grained EMA data support the SCS’s conceptualization as a state-like. • EMA SCS scores fluctuate over time with extreme shifts being unlikely. • Predictive validity and clinical utility of the SCS need to be further examined. The present work psychometrically evaluates a brief self-report questionnaire and novel ecological momentary assessment (EMA) items to assess the Suicide Crisis Syndrome (SCS). Data from n = 220 psychotherapy outpatients (sample 1) and n = 142 psychiatric inpatients after a suicide attempt or suicidal crisis (sample 2) are analyzed (cross-sectional, study 1; 21 to 24 day EMA, study 2). Dimensionality is examined by exploratory factor analysis in sample 1 and subsequently cross-validated by confirmatory factor analysis (CFA) in sample 2 (self-report questionnaire). Convergent validity is determined by correlation analysis. Dimensionality is examined by multilevel CFA. Temporal instability and associations of the SCS with affect, context and sleep are examined. Unidimensionality of both measures is supported with good to excellent reliability (α = 0.83 in sample 1, ϖ = 0.91 in sample 2 [self-report questionnaire]; ϖ = 0.83 prompt-level and ϖ = 0.94 person-level [EMA]). Correlations supported convergent validity. The SCS fluctuated moderately over time (with 26 % of the variance being attributable to changes on the within-person level and high heterogeneity between participants) with extreme shifts being not very likely. The EMA SCS items appeared to be context-sensitive and vary according to sleep quality and valence of affective states. The self-report questionnaire and the novel EMA items are brief and reliable tools to repeatedly assess the SCS. The study demonstrates for the first time that the SCS can be assessed at the moment and waxes and wanes over time.