Internal consistency and factor structure of the Portuguese version of the Liebowitz Social Anxiety Scale among alcoholic patients Consistência interna e estrutura fatorial da versão em português da Escala de Ansiedade Social de Liebowitz entre pacientes alcoolistas

Abst rac t Objective: Liebowitz Social Anxiety Scale is an instrument used to evaluate the severity of social phobia. It has been widely used in different contexts and cultures, presenting variable psychometric properties. The objective of this article is to investigate the internal consistency and the factor structure of this scale. Method: In a sample of 300 alcoholic patients hospitalized in 3 mental clinics in Southern Brazil, 74 of them were social phobics (24.6%). The Structured Clinical Interview for DSM-IV-Axis I Disorders – Patient Edition, a semi-structured clinical interview based on DSM-IV, was used to check for the diagnosis of social phobia. The internal consistency was measured by Cronbach’s alpha. Data were subjected to a factor analysis with the principal component method of parameter estimation. Questionnaire items loading at 0.35 or above were considered in the final factor solution. Results: The coefficient of internal consistency was 0.95. All items showed corrected item-total correlation coefficient above 0.15, considered the minimum requested index. The factor analysis resulted in 5 dimensions which corresponded to 52.9% of the total variance. The five factors extracted were: factor I – speaking in a group, factor II – activity in public, factor III – social interaction with unknown person, factor IV – attitude of disagreement or disapproval and factor V – social interaction in leisure activity. Conclusions: The scale proved to be reliable and structurally valid instrument for use in a population of alcoholic patients. The possibility of screening for social phobia through the use of the instrument may be helpful in identifying probable cases of the disorder among alcoholics.