Reliability and Validity of the Adaptive Cognition About Sleep-2, an Abbreviated Version of the Adaptive Cognition and Behaviors About Sleep-6

Background and Objective The Adaptive Cognition and Behaviors about Sleep-6 (ACBS-6) comprises two factors, adaptive sleep-related cognitions (Items 1–4) and behaviors (Items 5 and 6). We aimed to develop a shortened version.Methods Four anonymous online surveys of Korean adults were analyzed. In a general-population derivation sample (n=600), items most relevant to adaptive sleep cognition and most strongly correlated with the Insomnia Severity Index (ISI) were selected. Their reliability and validity were checked among three independent validation samples such as the general population (n=600), respondents reporting insomnia (n=600), and respondents reporting insomnia and taking hypnotics (n=500). Internal consistency was estimated with the Spearman–Brown-corrected split-half coefficient. Mediation analyses explored whether adaptive cognition mediates the association between insomnia severity and the two-item questionnaire version of the discrepancy between desired time in bed and desired total sleep time (DBSTq-2).Results ACBS-6 Items 2 and 4 were selected as the Adaptive Cognition about Sleep-2 (ACS-2). The split-half coefficient ranged from 0.59 to 0.75. The ACS-2 score was inversely correlated with the ISI in all four samples (r=-0.14 to -0.23, all p<0.01), and its correlation with the Dysfunctional Beliefs and Attitudes about Sleep-6 items ranged from -0.11 to 0.08. The ACS-2 did not mediate the association between the DBSTq-2 and the ISI.Conclusions The ACS-2 is a feasible brief rating scale measuring adaptive cognition about sleep. Adaptive cognition appears to be distinct from dysfunctional beliefs about sleep, and not the opposite pole of the same dimension.