Copyright © 2018 the Author(s). High harm avoidance (HA) scores on the temperament and character inventory appear to be a risk factor for depressive disorders and suicide. Since 2012, we have conducted group cognitive behavioral therapy (G-CBT) interventions for students at Nagasaki University with high HA and without depressive disorders, with the aim of preventing depression. Here, we report on the effects of the G-CBT at 1-year follow-up for the 2012 to 2015 period. Forty-two participants with high HA were included in the final analysis. Outcomes were measured with the Beck Depression Inventory II, Manifest Anxiety Scale, 28-item General Health Questionnaire, and Brief Core Schema Scales at baseline, and at 6-month, and 1-year follow-ups. Repeated-measures analyses of variance revealed a significant decrease in mean depressive symptom scores at the 6-month follow-up point; this decrease was maintained at 1 year. Improvements in cognitive schemas were also seen at 6 months and 1 year. We observed improvements in cognitive schemas associated with depression as a result of the G-CBT intervention, with effects maintained at 1 year post-intervention. This intervention may be effective in positively modifying the cognitions of students with HA and preventing future depression.