Telephone Cognitive-Behavioral Therapy for Subthreshold Depression and Presenteeism in Workplace: A Randomized Controlled Trial

Toshi A Furukawa,Norito Kawakami,Masayo Kadota,Louis C Grothaus,Hiroki Hosogoshi,Masaru Horikoshi,Yuki Sekiya,Minoru Nagasaku,Hitomi Terashima,Masami Kashimura,Kenichi Asano,Megumi Sasaki,Kazunori Iwasa,Isabelle Boutron

doi:10.1371/journal.pone.0035330

Abstract

BackgroundSubthreshold depression is highly prevalent in the general population and causes great loss to society especially in the form of reduced productivity while at work (presenteeism). We developed a highly-structured manualized eight-session cognitive-behavioral program with a focus on subthreshold depression in the workplace and to be administered via telephone by trained psychotherapists (tCBT).MethodsWe conducted a parallel-group, non-blinded randomized controlled trial of tCBT in addition to the pre-existing Employee Assistance Program (EAP) versus EAP alone among workers with subthreshold depression at a large manufacturing company in Japan. The primary outcomes were depression severity as measured with Beck Depression Inventory-II (BDI-II) and presenteeism as measured with World Health Organization Health and Work Productivity Questionnaire (HPQ). In the course of the trial the follow-up period was shortened in order to increase acceptability of the study.ResultsThe planned sample size was 108 per arm but the trial was stopped early due to low accrual. Altogether 118 subjects were randomized to tCBT+EAP (n = 58) and to EAP alone (n = 60). The BDI-II scores fell from the mean of 17.3 at baseline to 11.0 in the intervention group and to 15.7 in the control group after 4 months (p<0.001, Effect size = 0.69, 95%CI: 0.32 to 1.05). However, there was no statistically significant decrease in absolute and relative presenteeism (p = 0.44, ES = 0.15, −0.21 to 0.52, and p = 0.50, ES = 0.02, −0.34 to 0.39, respectively).ConclusionRemote CBT, including tCBT, may provide easy access to quality-assured effective psychotherapy for people in the work force who present with subthreshold depression. Further studies are needed to evaluate the effectiveness of this approach in longer terms. The study was funded by Sekisui Chemicals Co. Ltd.Trial RegistrationClinicalTrials.gov NCT00885014

Highlights

Subthreshold depression, variably defined as depressive state failing to reach the diagnostic threshold for major depression and sometimes called subsyndromal depression or minor depression, is highly prevalent, clinically relevant and societally important
The present study focused on subthreshold depression in the workplace, targeting both depression itself and associated decreased productivity, through the novel cognitive-behavioral therapy (CBT) method of delivery using the telephone
Cf. below) and to answer the telephone interview when invited for the ultimate purpose of participating in the intervention study. Those scoring 9 or higher on K6 were invited for the telephone interview by a trained interviewer using the Composite International Diagnostic Interview, mood and substance sections, and to fill in the Beck Depression Inventory-II (BDI-II)

Summary

Introduction

The prevalence of subthreshold depression has been estimated at around 5–20% in the community and in the primary care patients [1,2,3] It is invariably associated with significant psychological suffering, functional impairment and decreased quality of life [1,4,5,6]. Subthreshold depression is a strong risk factor for major depression both in the short [7] and long [8] terms. Given this high prevalence and significant morbidities, subthreshold depression represents a substantive burden on the society. We developed a highly-structured manualized eight-session cognitive-behavioral program with a focus on subthreshold depression in the workplace and to be administered via telephone by trained psychotherapists (tCBT)

Methods

Results

Conclusion