RESUMEN
Demoralization comprises multiple dimensions. Among them, Subjective Incompetence (SI) is the perception of being incapable of appropriate action in demanding circumstances. SI may be an early sign of demoralization preceding hopelessness, thus we aimed at integrating items related to Subjective Incompetence into the clinical assessment of demoralization. We assessed 414 subjects from the general population with the Demoralization Scale, 24 items (DS24) and the Subjective Incompetence Scale, 12 items (SIS12). We used multiple approaches to detect the optimal number of factors and their item structure, then conducted Bayesian Item Response Theory analyses to study item psychometric properties. Item Response Theory models were used to extrapolate latent severity ratings of clinical dimensions. We modelled the DS24 with five factors (Disheartenment, Sense of Failure, Helplessness, Irritability, Loss of Purpose) and the SIS12 with three (Subjective Incompetence, Inability to plan, Inability to Deal). The more complex IRT model had the best predictive value and helped to identify the items with better discrimination properties across the different dimensions. Twenty items were retained and used to develop the combined Demoralization and Subjective Incompetence Scale (DSIS20), which maintained high correlation with raw and latent trait scores of the longer versions. We combined selected items of the DS24 and the SIS12 to develop the DSIS20, a shorter assessment instrument that includes Subjective Incompetence as well as other clinical dimensions of demoralization. Further study may clarify if DSIS20 may be helpful for the early detection of demoralization.