Abstract
OBJECTIVES: To verify the effects of organizational interventions on mental health using Layered Voice Analysis (LVA). METHODS: A 12-week single-blind randomized controlled trial was conducted with call center operators. Sixty-six participants were randomly assigned to either a control group (n = 26), an LVA intervention group (n = 20), or a one-on-one intervention group (n = 20). The control group received general self-care information about preventing mental health problems from the Ministry of Health, Labour, and Welfare, Japan website. The organizational LVA intervention involved group sessions using participants' voice calls with customers, whereas the one-on-one intervention consisted of meetings or consultations with participants and their supervisors to discuss preventing mental health issues at work. To verify the effectiveness of the intervention program, the Center for Epidemiologic Studies Depression Scale (CES-D) was administered 4 times (baseline, 4, 8, and 12 weeks) as the primary outcome, and the data were analyzed using a linear mixed model. The intervention of LVA was subdivided and analyzed into LVA ≥5 times and LVA ≤4 times out of the total 6 interventions. RESULTS: Compared with the control group, a significant CES-D reduction effect was observed at 8/12 weeks for the difference of coefficients (DOC; [βint - βctrl]) for the intervention of LVA ≥5 times (DOC -1.86 and -2.36, respectively). Similarly, even intervention LVA ≤4 times also showed a significant decrease of CES-D scores at 8/12 weeks (DOC -2.20 and -2.38, respectively). CONCLUSIONS: An organizational intervention using LVA has the potential to reduce the risk of depression among call center operators.