Cognitive behavioral therapy for stress-related disorders

Abstract

Background: Stress-related disorders in the form of adjustment disorder (AD) and exhaustion disorder (ED) are prevalent and associated with significant suffering, functional impairment and high societal costs. Cognitive behavioral therapy (CBT) may be effective in reducing stress, but studies using clinical samples diagnosed with stress-related disorders are few, and evidence is lacking to support treatment guidelines. Because accessibility to CBT is limited, it is important to investigate treatment delivery formats that enable high scalability. Health economic evaluations of treatments are needed to guide decision makers in how to use limited healthcare resources efficiently. Further, the study of potential mediators of treatment effect is important to inform treatment development for patients diagnosed with AD or ED.

Aims: The overall aim of Study I was to evaluate the effect of CBT, a return-to-work intervention (RTW-I), and a combination of the two (COMBO) for patients on sick leave due to a common mental disorder (CMD; AD, ED, anxiety disorders, depression, and insomnia). Of particular interest to the present thesis was to evaluate the effect of a new CBT protocol used to treat patients with stress-related disorders in Study I. In Study II, the aim was to evaluate the efficacy of that same CBT protocol when delivered as a therapist-guided internet-based treatment (ICBT) for individuals with AD or ED. In Study III, we aimed to investigate cost-effectiveness of the ICBT. In Study IV, we aimed to investigate sleep impairment as a putative mediator of the effect of ICBT on symptoms of stress and exhaustion.

Methods: In Study I, consecutively recruited primary care patients (N = 211) who were on sick leave due to a CMD were randomized to disorder specific CBT, a RTW-I, or to COMBO. Main outcomes were symptom severity and net days on sick leave. Of the total sample, a majority (72%) of patients met diagnostic criteria for AD or ED and were treated with the new CBT protocol for stress-related disorders. In Study II, nationally recruited participants (N = 100) diagnosed with AD or ED were randomized to ICBT for stress-related disorders or to a waitlist control condition (WLC). Level of perceived stress was the main outcome. Studies III and IV were based on data collected in Study II. In Study III, cost-effectiveness and cost-utility of the ICBT were evaluated from a societal and a healthcare perspective, using remission rates and health-related quality of life to calculate incremental cost-effectiveness and cost-utility ratios respectively. In Study IV, weekly measurements of sleep impairment (the putative mediator) and outcomes (perceived stress and exhaustion) throughout the course of ICBT were analyzed using latent growth models within a structural equation framework.

Results: Results of Studies I and II indicated that the CBT for stress-related disorders was effective in reducing symptoms compared with the RTW-I and the WLC respectively. Subgroup analyses of AD and ED in Study II indicated that the treatment was equally effective for both diagnostic groups. Treatment effect on sick leave (Study I) and work ability (Study II) was, however, small and non-significant compared with control conditions. Results from Study III suggested that, compared with the WLC, ICBT was a cost effective treatment, yielding large effects at no or minimal societal net costs in only 12 weeks. In Study IV, reduced sleep impairment was found to statistically mediate the effect of ICBT on symptoms of perceived stress and exhaustion.

Conclusions: A relatively short CBT protocol designed to meet the presumed needs of patients diagnosed with AD or ED was indicated to be effective in reducing symptoms both when delivered as a face-to-face treatment and when delivered via the internet. If implemented in routine care, ICBT has the potential to increase access to efficacious treatment for many suffering individuals at no additional societal net costs. Reduced sleep impairment may be of importance to achieve successful treatment outcomes. The results motivate further investigation of the treatment using different control groups, longer follow-up periods, and more fine-grained evaluations of treatment mechanisms. Further investigation into interventions that may have an effect on work-related outcomes is warranted.