Abstract
Objectives: Efforts to improve performance in the workplace with respect to positive mental health have increased, and cognitive behavioral therapy (CBT) has recently attracted attention as an intervention measure to this end. Here, we conducted a randomized controlled trial to evaluate the effectiveness of a brief training program on CBT for improving work performance of employees. Methods: The participants were employees of an electric company in Japan. The intervention consisted of 1 group session of CBT (120 min) and web-based CBT homework for 1 month. We evaluated employees in both the intervention and control groups at baseline and follow-up after three months. The main outcome was work performance, which was evaluated by a subjective score from 1 to 10. The secondary outcome was self-evaluation of cognitive flexibility. Analyses were conducted based on ITT. Results: In the intervention group, 84 participants attended the group session, with 79 subsequently completing at least 1 instance of online homework. ITT analysis showed that the subjective performance of the intervention group was significantly improved compared with that of the control group (1.47 vs. 0.69, mean difference 0.78 [95% confidence interval {CI}, 0.05 to 1.51], Cohen's d=0.31). The ability to recognize dysfunctional thinking patterns and change them to positive ones significantly improved in the intervention group compared to the control group (0.71 vs. 0.26, mean difference 0.45 [95% CI 0.06 to 0.83], d=0.33). However, after adjustment for baseline scores, no significant difference was observed. The ability to view a situation from multiple perspectives and expand one's repertoire of thought patterns in the intervention group also significantly improved (0.83 vs. 0.35, mean difference 0.48 [95% CI 0.35 to 0.95], d=0.29), but here again, significance was lost after adjusting for baseline scores. Discussion: Our results suggest that a brief training program that combines a group CBT session with web-based CBT homework improved subjective work performance. In addition, this program might help improve employees' cognitive flexibility.(J Occup Health 2015; 57: 169–178)
