[Internal structure of Dysfunctional Beliefs and Attitudes about Sleep Scale in a Spanish shift workers sample]

Dysfunctional beliefs are some of the psychological factors that explains the origin and maintenance of insomnia. Morin developed a five theoretical dimension scale, the Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS), to assess them.

To analyze the internal structure of the Spanish version of DBAS, and to establish the differences on DBAS scores between two groups above described.

The sample was 237 workers of those 197 were shift workers and the rest had a stable timetable (mean age = 43.07; standard deviation = 9.39). The DBAS and the Pittsburgh Sleep Quality Index was administrated to them.

The results of the items analysis and reliability of each five dimensions were moderate, except for the first and second dimension of Morin's proposal. Confirmatory factorial analysis isolated four factors: consequences of the insomnia on the diurnal yield/functioning (alpha = 0.75); control and prediction of the sleep (alpha = 0.70); consequences of the insomnia on the physical and mental health (alpha = 0.69), and expectations on the association sleep-age (alpha = 0.60). It was corroborated that either first, second or third factor allowed differentiating one group of another.

All these results allowed us to consider Spanish version of DBAS as an appropriated 18 items adapted version. The structure of four factors is theoretically coherent, and it shows an adequate internal consistency and high capacity to differentiate well from bad sleepers.