Factor structure and psychometric properties of the Pittsburgh Sleep Quality Index in community-based adolescents.

Study Objectives: The Pittsburgh Sleep Quality Index (PSQI) is a widely used self-report questionnaire that assesses general sleep quality. This study aimed to validate the single-factor scoring structure and related psychometric properties in the English language version of the PSQI in community-based adolescents. Methods: Participants were 889 (352 males, 39.6%) students (age M = 15.71 ± 1.57; 12.08-18.92 years) recruited from 14 Australian secondary schools. Participants completed the PSQI, Center for Epidemiological Studies-Depression (CES-D) scale, and Spence Children's Anxiety Scale (SCAS). Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) of PSQI component scores were performed on two independent random half-samples (i.e. cross-validation approach). The internal consistency of PSQI components and convergent validity of the PSQI global score with CES-D and SCAS total scores were also assessed. Results: EFA yielded a single-factor model. CFA of the single-factor model in a separate sample yielded acceptable model fit to the data after important relationships were modeled. Namely, modification indices suggested improved model fit by correlating residual scores of PSQI components of sleep duration and sleep efficiency, and sleep efficiency and sleep latency. Internal consistency was acceptable (Cronbach's α = 0.73). The PSQI global score had moderate-to-large positive correlations with CES-D (r = 0.58) and SCAS (r = 0.45) total scores, demonstrating good convergent validity with emotional problems as predicted. Conclusions: The findings validate the single-factor scoring structure of the PSQI in an adolescent sample and highlight important covariation between poor sleep duration, efficiency, and latency in this age group. Further validation studies are required to determine an appropriate PSQI clinical cut-off score for adolescents.

Systematic Review and Meta-analysis of Adolescent Cognitive-Behavioral Sleep Interventions.

This systematic review and meta-analysis examined the efficacy of adolescent cognitive-behavioral sleep interventions. Searches of PubMed, PsycINFO, CENTRAL, EMBASE, and MEDLINE were performed from inception to May 1, 2016, supplemented with manual screening. Nine trials were selected (n = 357, mean age = 14.97 years; female = 61.74%). Main outcomes were subjective (sleep diary/questionnaire) and objective (actigraphy) total sleep time (TST), sleep onset latency (SOL), sleep efficiency (SE), and wake after sleep onset (WASO). There were a small number of randomized controlled trials (RCTs; n = 4) and a high risk of bias across the RCTs; therefore, within sleep condition meta-analyses were examined (n = 221). At post-intervention, subjective TST improved by 29.47 min (95% CI 17.18, 41.75), SOL by 21.44 min (95% CI -30.78, -12.11), SE by 5.34% (95% CI 2.64, 8.04), and WASO by a medium effect size [d = 0.59 (95% CI 0.36, 0.82)]. Objective SOL improved by 16.15 min (95% CI -26.13, -6.17) and SE by 2.82% (95% CI 0.58, 5.07). Global sleep quality, daytime sleepiness, depression, and anxiety also improved. Gains were generally maintained over time. Preliminary evidence suggests that adolescent cognitive-behavioral sleep interventions are effective, but further high-quality RCTs are needed. Suggestions for further research are provided.

Sleep Duration and Sleep Quality: Associations With Depressive Symptoms Across Adolescence.

This study explored whether short sleep duration and sleep quality mediate the relationship between age and depressive symptoms. For comparison, we also explored whether depressive symptoms mediate the relationship between age and short sleep duration and sleep quality. The sample comprised 741 adolescents (63.5% female, mean age 15.78 years, range 11.92-19.67 years) in grades 7-12 from 11 secondary schools in metropolitan Melbourne, Australia. Students completed the Pittsburgh Sleep Quality Index (PSQI) and Center for Epidemiologic Studies Depression Scale (CES-D). Path analyses suggested that short sleep duration significantly mediated the relationship between age and depressive symptoms. Poor sleep quality also significantly mediated this relationship when sleep quality was defined by subjective judgement, but not sleep disturbance, sleep efficiency, or sleep onset latency. Depressive symptoms significantly mediated the relationship between age and short sleep duration and sleep quality (subjective judgement, sleep disturbance, sleep efficiency, and sleep onset latency). These findings suggest that the population-wide increase in depressive symptoms across adolescence is partially mediated by sleep-related developmental changes. They also highlight the importance of examining specific sleep problems when investigating the relationship between sleep and mood in this age group.