[Validation of the Spanish version of the Liebowitz social anxiety scale, social anxiety and distress scale and Sheehan disability inventory for the evaluation of social phobia].

BACKGROUND: Social phobia is an anxiety disorder of increasing interest in clinical psychiatric practice and research. The questionnaires most widely used in the psychometric evaluation of these patients are: Liebowitz Social Anxiety Scale (LSAS), Social Anxiety and Distress Scale (SADS) and Sheehan Disability Inventory (SDI). The objective of this study was to evaluate the validity and reproducibility of the Spanish versions. SUBJECTS AND METHODS: Convergent validity was analysed by correlating patients' scores on the LSAS, SADS and SDI with scores on the Global Activity Evaluation Scale (GAES), the Hamilton Anxiety Scale (HAM-A) and the Visual Analogue Scale (VAS) of the EuroQol. Validity of the internal structure was examined by analysing the correlations between the different sub-escales of the questionnaires. Internal consistency was analysed using Cronbach's alpha and Kuder-Richardson coefficients. Discriminative capability was analysed by comparing LSAS, SADS and SDI scores of patients with social phobia with scores from healthy subjects, and with that obtained on the HAM-A and the EuroQol VAS. Reproducibility was analysed by re-testing patients after 15 days.
RESULTS: 57 patients and 57 healthy subjects were recruited in 4 psychiatric centres. The three questionnaires showed an adequate convergent validity with the GAES, the HAM-A and the EuroQol VAS (r = -0.24-0.40 and r = 0.29-0.52). The LSAS and SDI questionnaires showed a homogenous internal structure in terms of correlation between sub-scales (r = -0.61-0.93 for LSAS, and r = -0.04-0.61 for SDI). All the sub-scales of the questionnaires showed an adequate internal consistency (with coefficients between 0.72 and 0.88). The questionnaires discriminated between groups of patients with different levels of symptom severity and self-perceived overall health. They also discriminated between patients with social phobia and healthy subjects (area under the Receiver's Operating Characteristics curves = 0.95-0.99). All sub-scales from the questionnaires showed adequate reproducibility (with intraclass correlation coefficients between 0.63 and 0.88).
CONCLUSIONS: The Spanish versions of the LSAS, SADS and SDI questionnaires have shown adequate validity and reproducibility for use in clinical research and the clinical assessment of patients with social phobia in Spain.