Changes in self-reported sleep and cognitive failures: a randomized controlled trial of a stress management intervention

Objectives This study evaluated the effectiveness of a stress management intervention combining individual cognitive behavioral therapy (CBT) with a brief workplace intervention on self-reported measures of sleep and cognitive functioning among patients on sick leave due to work-related stress complaints. Methods Participants were patients referred to the regional Department of Occupational Medicine. Inclusion criteria were (i) sick leave due to work-related stress complaints and (ii) a diagnosis of adjustment disorder/reactions to stress or mild depression. Participants (N=137) were randomized to either an intervention (N=57) or control (N=80) group. The intervention comprised six sessions with a psychologist and the offer of a small workplace intervention. Questionnaires were answered at baseline and after 4, and 10 months. Results Symptoms were significantly reduced over time in both groups but there was no significant treatment effect on sleep or cognitive outcomes at any time point. From 0-4 months, there was a tendency for larger improvements in the intervention group with regards to sleep and cognitive failures in distraction. Although neither was significant, the results came close to significance depicting a small effect size (Cohen's d) on sleep complaints and distractions (but not memory). Conclusions The specific intervention was not superior to the control condition in reducing symptoms of sleep problems and cognitive difficulties at any time point during the 10-month follow-up period. Substantial improvements in symptoms over time were seen in both groups.