[Instrument for measuring psychological variables and adherence to treatment behavior in persons who are seropositive for HIV (VPAD-24)].

Objective: To test the psychometric properties of an instrument for measuring psychological variables and adherence to treatment behaviors in persons with HIV infection or AIDS.

Methods: A cross-sectional study was performed with 68 subjects who were seropositive for the human immunodeficiency virus (HIV) and who were being treated in a health facility in the city of Hermosillo (Sonora), Mexico, at the time the study was carried out. Five consecutive statistical testing procedures were applied for data analysis: the Student t test for comparison of means, for assessing the comprehensibility of the questions; an exploratory factorial analysis with varimax rotation for determining construct validity; Cronbach's alpha coefficient for determining reliability; Pearson's correlation coefficient (r) for assessing concurrent validity; and multiple linear regression for determining predictive value.