The Chronic Sleep Reduction Questionnaire (CSRQ): a cross-cultural comparison and validation in Dutch and Australian adolescents JULIA F. DEWALD 1 , MICHELLE A. SHORT 2 , MICHAEL GRADISAR 2 , FRANS J. OORT 1 and ANNE MARIE MEIJER 1 1 Research Institute of Child Development and Education, Faculty of Social and Behavioral Sciences, University of Amsterdam, Amsterdam, the Netherlands and 2 Flinders University, School of Psychology, Adelaide, South Australia Keywords adolescents, chronic sleep reduction, psychometric properties, school performance, sleep Correspondence Julia F. Dewald, Research Institute of Child Development and Education, Faculty of Social and Behavioral Sciences, University of Amsterdam, Nieuwe Prinsengracht 130, 1018 VZ Amsterdam, the Netherlands. Tel.: +31-20-525-1280, fax: +31-20-525-1200; e-mail: j.f.dewald@uva.nl Accepted in revised form 7 January 2012; received 6 June 2011 DOI: 10.1111/j.1365-2869.2012.00999.x SUMMARY Although adolescents often experience insufficient and ⁄ or poor sleep, sleep variables such as total sleep time do not account for individualsÕ sleep need and sleep debt and may therefore be an inadequate representation of adolescentsÕ sleep problems and its daytime conse- quences. This problem can be overcome by using the Chronic Sleep Reduction Questionnaire (CSRQ), an assessment tool that measures symptoms of chronic sleep reduction and therefore accounting for sleep need and sleep debt. The present study aims at developing an English version of the CSRQ and assesses the reliability and validity of the Dutch and the English CSRQ version. The CSRQ was administered in large Dutch (n = 166, age = 15.2 ± 0.57 years, 28% male) and Australian (n = 236, age = 15.5 ± 0.99 years, 65% males) samples. Subjective sleep variables were measured with surveys and sleep diaries of five school nights. Additionally, sleep of the same five nights was monitored with actigraphy. Both CSRQ versions showed good psychometric properties concerning their reliability (Dutch: a = 0.85; English: a = 0.87) and validity as the same overall structure of the two CSRQ versions and significant correlations with subjective and objective sleep variables were found. School grades were related to chronic sleep reduction, whereas the relationship between grades and other sleep variables was weak or absent. These results highlight the idea that chronic sleep reduction may be a better indicator of adolescentsÕ insufficient and ⁄ or poor sleep than other sleep variables such as total sleep time. INTRODUCTION Adolescents sleep less than younger children, although it has been shown that their objective need for sleep does not decrease during the pubertal transition (Carskadon et al., 1993). Eleven to 47% of adolescents report poor sleep (Liu and Zhou, 2002; Russo et al., 2007), and more than 50% sleep less than the ideal 9 h per night (Gibson et al., 2006). This phenomenon can be caused by an interaction of intrinsic (e.g. puberty, circadian and ⁄ or homeostatic changes) and extrinsic factors (e.g. social pressure, academic workload) causing later bedtimes, while rise times remain unchanged due to early school start times (Wolfson and Carskadon, 2003). As most adolescents experience these sleep prob- lems over a long period of time, it can be assumed that many suffer from chronically reduced sleep (Loessl et al., 2008; Meijer, 2008). Over time, chronic sleep reduction can result in severe psychological and physiological consequences such as behavioural problems, poor emotional wellbeing, impaired cognitive and school performance and even detrimental neurobiological changes (Curcio et al., 2006; Mitru et al., 2002; Moore and Meltzer, 2008; Wolfson and Carskadon, 2003). The problem of chronic sleep reduction during adole- scence is a worldwide existing and well-known phenomenon. However, due to a lack of consensus concerning the J. Sleep Res. (2012) 21, 584–594 Assessing chronic sleep reduction 584 ª 2012 European Sleep Research Society