Validation of the University of São Paulo Sensory Phenomena Scale: initial psychometric properties

Although obsessions and compulsions comprise the main features of obsessive-compulsive disorder (OCD), many patients report that their compulsions are preceded by a sense of "incompleteness" or other unpleasant feelings such as premonitory urges or a need perform actions until feeling "just right." These manifestations have been characterized as Sensory Phenomena (SP). The current study presents initial psychometric data for a new scale designed to measure SP.

Seventy-six adult OCD subjects were probed twice. Patients were assessed with an open clinical interview (considered as the "gold standard") and with the following standardized instruments: Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis I Disorders, Yale-Brown Obsessive-Compulsive Scale, Dimensional Yale-Brown Obsessive-Compulsive Scale, Yale Global Tic Severity Scale, Beck Anxiety Inventory, and Beck Depression Inventory.

SP were present in 51 OCD patients (67.1%). Tics were present in 16 (21.1%) of the overall sample. The presence of SP was significantly higher in early-onset OCD patients. There were no significant differences in the presence of SP according to comorbidity with tics or gender. The comparison between the results from the open clinical interviews and the University of São Paulo Sensory Phenomena Scale (USP-SPS) showed an excellent concordance between them, with no significant differences between interviewers. The inter-rater reliability between the expert raters for the USP-SPS was high, with K=.92. The Pearson correlation coefficient between the SP severity scores given by the two raters was .89.

Preliminary results suggest that the USP-SPS is a valid and reliable instrument for assessing the presence and severity of SP in OCD subjects.