Assessment of beliefs about treatment:: Validity and reliability of the Spanish version of the Beliefs about Medicines Questionnaire

The Beliefs about Medicines Questionnaire was designed to assess the cognitive representation of medication. The BMQ consists of two sections: the BMQ-General and the BMQ-Specific. The aim of this instrumental study was to assess the factor structure and reliability of the Spanish version of the BMQ. In order to analyse the properties of the BMQ-Specific, a sample of 156 patients, 97 diabetics with insulin treatment and 59 patients with hypertensive treatnent were used. The BMQ-General was studied with the chronic patients and with 256 undergraduates. As in the original version, for each section in the BMQ a bifactorial pattern was found. Its validity to discriminate between patients with different types of treatment was proved. Patients with insulin treatment had significantly higher scores on Specific-Necessity Scale than hypertensive patients. The internal consistency of the BMQ Scales was adequate in the three samples. The Spanish version of the BMQ is a valid and reliable instrument for assessing beliefs about medicines but additional research is needed not only with other groups of patients and types of treatment but also to study the relationships between the BMQ and the treatment adherence.