Arousability and insomnia: validation of the Italian version of the arousability predisposition scale (APS)

Arousability has been described as a predisposing factor for insomnia (e.g. Lundh, Broman, 2000). Coren (1988) supposed that insomnia could be predicted by a long term stable trait of hyperarousability. In order to assess this hypothesis, the author developed a 12 items self-report scale (Arousability Predisposition Scale, APS) and found it to be a good predictor of sleep disturbances. The aim of this study was to validate an Italian version of the APS in a sample of 348 participants (61.0% F, 36.7% M) categorised on the bases of the self-reported quality of their sleep in three groups: good sleepers (GS), people with subthreshold insomnia (SI) and people with insomnia (PI). Participants were recruited among family physician patients from three central Italy areas. First it was conducted an explorative factorial analysis applied to the items of the APS (method Maximum Likelihood). Based on the scree test, one factor was chosen accounting for the 38.04% of the total variance. Two items with communalities lower than 0.25 were excluded. In order to confirm this 10-items monofactorial solution, structural equation models were conducted and results showed good indices of fit (RMSR50.064; CFI50.95; TLI50.93). The Chronbach’s alpha indicated good reliability (a50.86). The test resulted also valid as indicated by the differences on the total score among the three Groups (F (2,328)524.84, Po0.001; GS: M514.82, SD56.31; SI: M517.53, SD56.97; PI: M522.66, SD57.13). Validity is also evidenced by high correlations with a subscale of arousability (.65) of another independent measure (Rome Arousability Scale, RAS, Violani et al. 2006). A brief and easy to use scale of Arousability as the APS has been found to be effective and predictive of insomnia also in the Italian version.