[Meta-analysis of group comparison and meta-analysis of reliability generalization of the State-Trait Anxiety Inventory Questionnaire (STAI)].

BACKGROUND Since its creation the STAI has been cited in more than 14,000 documents, with more than 60 adaptations in different countries. In some adaptations this instrument has no clinical scores. The aim of this work is to determine if the State-Trait Anxiety Inventory (STAI) has higher scores in patients diagnosed with anxiety than in general population. In addition, we want to examine if the internal consistency is adequate in anxious patient samples. METHODS We performed a literature search in Tripdatabase, Cochrane, Web of Knowledge, Scopus, PyscINFO and Scholar Google, for documents published between 2008 y 2012. We selected 131 scientific articles to compare between patients diagnosed with anxiety and general population, and 25 for the generalization of reliability. For the analysis we used Cohen's d for means comparisons (random-effects method) and Cronbach's alpha for the reliability generalization (fixed-effects method). RESULTS In the groups comparision the differences in state anxiety (d=1.39; CI95%: 1.22-1.56) and in the trait anxiety (d=1.74; CI95%:1.56-1.91) were significants. The reliability for patients of some anxiety disorder was between 0.87 and 0.93. CONCLUSIONS So it seems that the STAI is sensitive to the level of anxiety of the individual and reliable for patients with diagnosis of panic attack, specific phobia, social phobia, generalized social phobia, generalized anxiety disorder, post-traumatic stress disorder, obsessive compulsive disorder or acute Stress disorder.