The struggle to fall asleep: Impulsivity as a risk factor for insomnia

Abstract

There is considerable evidence that individuals suffering from insomnia experience unwanted intrusive and worrisome thoughts during sleep onset and that they attribute their sleep disturbances to a "racing minci" (for a review, see Harvey, 2005). There is also growing evidence that thought suppression might fuel the experience of negative cognitive arousal during sleep onset, thereby contributing to the maintenance of insomnia (for reviews, see Espie, 2002; Harvey, 2002) .. Research has, for example, shown that insornniacs report using suppression during the presleep period more than good sleepers do (Harvey, 2001), and that the more frequent use of suppression is associated with more frequent sleep-interfering thoughts and poorer sleep quality (Ree et al, 2005) Comparatively little is known about personality factors that might predispose people to suppress unwanted intrusive thoughts when trying to fall asleep.. Despite ils prominent status in psychopathology, impulsivity has rarely been considered as a potential risk factor for insomnia in previous research, and the few studies that have done so produced equivocal evidence (Dorsey & Bootzin, 1997; lreland & Culpin, 2006; Lundh et al, 1995). Meanwhile, indirect evidence continues to hint at a possible link between impulsivity and insomnia, for example, well-documented sleep disturbances in irnpulsivity-related disorders such as borderline personality disorder (de la Fuente et al., 2001; Lindberg et al., 2003). The purpose of the present study was to investigate the relationship between impulsivity and insomnia based on the comprehensive approach to irnpulsivity proposed by Whiteside and Lynam (2001). According to these authors, four facets of impulsivity can be distinguished: urgency, lack of premeditation, lack of perseverance, and sensation seeking. The present study involved 233 undergraduate students who completed Whiteside and Lynam's UPPS Impulsive Behavior Scale, Morin's (1993) Sleep lmpairment Index, and a short questionnaire on hypnagogic and dreamlike mentation. The main findings were that bath urgency and lack or perseverance was related to insornnia severity. Furthermore, urgency was associated with frequency of aggressive suppression of unwanted thoughts, and with frequency of upsetting thoughts at sleep onset Critically, the effect of urgency on difficulty in falling asleep was partially mediated by frequency of upsetting thoughts and images at sleep onset To our knowledge, the present study is the first to provide clear evidence for a link between two facets of impulsivity (urgency, lack of perseverance) and insomnia, and for a link between urgency and sleep-interfering cognitive activity.. The specific relations between facets of impulsivity and aspects of insornnia might open up new avenues for modeling the development and maintenance of insomnia and for clinical interventions.