Effects of a Group-Based Cognitive Behavioral Therapy for Sleep in Nursing Students: Pilot Randomized Controlled Trial.

Background: Sleep quality is a strategic public health priority and a key factor in the study of circadian rhythms and chronotypes. Nursing students are a particularly vulnerable population group. Objective: The objective of this study was to evaluate the effects of a brief group-based cognitive behavioral therapy for insomnia (CBT-I) intervention on sleep quality and circadian-related outcomes among first-year nursing students using ambulatory circadian monitoring. Methods: This study is a 2-arm pilot randomized clinical trial conducted at a private university in Madrid, Spain, from October 2022 to March 2023. First-year nursing students aged 18 to 25 years were recruited in October 2022 using convenience sampling and randomly assigned to an experimental group (n=20) that received a cognitive-behavioral intervention using an active-constructive learning methodology to improve sleep quality and a control group (n=20) that followed their usual daily routine. Primary outcomes were objective sleep quality assessed using the Kronowise 3.0 ambulatory circadian monitoring system and subjective sleep quality assessed using the Pittsburgh Sleep Quality Index (PSQI). The objective Kronowise assessment was characterized by the continuous circadian rhythm and sleep parameters generated by the device. Participant satisfaction with the intervention was evaluated using an adapted 12-item Likert-type satisfaction questionnaire administered after the intervention. Measurements were collected preintervention and postintervention over 7-day monitoring periods. Adjusted analyses were performed using analysis of covariance, with treatment group as the fixed factor and baseline values, smoking status, school schedule, and coffee consumption as covariates. Treatment effects were summarized using regression coefficients (β), 95% CIs, and partial eta-squared (η²). The study was conducted in accordance with the CONSORT (Consolidated Standards of Reporting Trials) statement. Results: Forty students (n=34, 85% female; mean age 19.9, SD 1.8 y) were randomized equally into the intervention and control groups. Adjusted analyses showed generally small treatment effects for objective circadian rhythm and sleep outcomes. The largest treatment effect was observed for self-reported sleep latency (β=-19.78 min, 95% CI -33.83 to -5.74; partial η²=0.194). Sleep duration (β=36.32 min, 95% CI -5.01 to 77.64; partial η²=0.086) and sleep efficiency (β=8.75%, 95% CI -0.97 to 18.47; partial η²=0.090) also favored the intervention group, although CIs indicated considerable uncertainty around these estimates. Participants reported high satisfaction with the intervention, with 65% (13/20) rating the program as "very good." Conclusions: This pilot randomized controlled trial provides preliminary evidence that a brief group-based CBT-I intervention may improve selected subjective sleep outcomes, particularly sleep latency, among first-year nursing students. Objective circadian rhythm and sleep outcomes showed generally small treatment effects. Given the exploratory nature of this pilot study, adequately powered randomized controlled trials with longer follow-up are needed to confirm these preliminary findings.