Sleep locus of control: report on a new scale.

The psychometric properties of a new 8-item measure, the Sleep Locus of Control Scale (SLOC), were investigated. A sample of 425 adult alumnae from the University of Manitoba and 57 community volunteers with chronic insomnia were surveyed. Results showed that the SLOC had acceptable reliability (i.e., internal consistency) and demonstrated convergent and discriminant validity through patterns of association with the Multidimensional Health Locus of Control Scale (Wallston, Wallston, & DeVellis, 1978). Principal factors extraction with varimax rotation identified two factors underlying the SLOC Scale. One factor captured an internal sleep locus of control orientation and the other reflected a chance sleep locus of control orientation. In the adult alumnae sample, having a more chance sleep locus of control was associated with greater perfectionism, depression, and anxiety. In adults with chronic insomnia, having a more internal sleep locus of control orientation was associated with increased sleep-related anxiety. One implication of the study is that too much emphasis on developing an internal sleep locus of control may be counterproductive (i.e., associated with increased sleep-related anxiety). Instead, achieving a balance between an internal and chance sleep locus of control orientation may be an important goal when treating individuals with chronic insomnia.