Spanish validation of the Gamblers' Belief Questionnaire (GBQ).

The objective of this study is to validate The Gambler's Beliefs Questionnaire, a measure of gamblers' cognitive distortions. The psychometric properties of the scale were analyzed with a Spanish sample of 515 participants aged from 16 and 24 years. Three scales related to pathological gambling (SOGS-RA and MAGS) and to social desirability were administered. A cross-sectional validation was performed, obtaining a scale with 21 items distributed in two independent factors (Luck/perseverance and Illusion of control). The internal consistency (α = .93) and test-retest reliability (r = .69) are adequate. GBQ scale scores correlate significantly with other measures of pathological gambling (SOGS: r = .35; MAGS: r = .40, both p ≤ .001). Higher levels of cognitive distortions are associated with a higher likelihood of being classified as a problem or at-risk gambler. GBQ scores are influenced by social desirability, although the effect sizes are small (r  below .20). The GBQ is a useful instrument in the diagnosis and evaluation of the treatment of Spanish youths and adolescents with gambling problems.