A psychometric analysis of the short forms of the 1978 version of the Beck Depression Inventory (BDI-IA)
Jesús Sanz and María Paz García-Vera
The psychometric properties of two short forms of the 1978 version of the Beck Depression Inventory (BDI-IA) were examined in three samples (psychopathological patients, general population, and university students). One short form (BDI-IA-SCA) is based on the cognitive-affective subscale of the BDI-IA; the other short form (BDI-IA-SF) is based on the BDI-SF. Reliability alpha coefficients for both short forms were similar and exceeded the standard of 0.70. Factor analyses suggested that both instruments measure a general dimension of depression composed of two highly related factors: a cognitive factor and a somatic one for the BDI-IA-SF, and a cognitive factor and an affective-motivational one for the BDI-IA-SCA. With two exceptions, all the symptomatic criteria proposed by the DSM-IV for major depressive and dysthymic disorders are accounted for the BDI-IA-SF; the BDI-IA-SCA is focused on affective-cognitive symptoms, and does not cover four somatic symptoms. Both instruments showed adequate indices of diagnostic accuracy, but there was no single cut-off score that allowed for a differential diagnosis between patients with or without depressive disorders. Both short forms can serve as reliable and valid substitutes for the BDI-IA when speed of administration is important.