AIM: To examine the effect of short-time video-based trauma-informed care (TIC) training in improving attitudes related to TIC and mental health among psychiatric nurses. METHODS: A nonrandomized controlled trial was conducted to investigate the effectiveness of a 60-min TIC training video. The primary outcome measure was the Attitudes Related to Trauma-Informed Care Scale 35 (ARTIC-35). The secondary outcome measures were the TIC Provider Survey, Kessler 6 (K6) scale, the Japanese Burnout Scale, and the Japanese Psychological Safety Scale. RESULTS: The main analysis included 100 psychiatric nurses (58 in the intervention group and 42 in the control group). The intention-to-treat (ITT) analysis showed that the increase in scores on ARTIC-35 was not statistically significant due to calculating the sample size based on an overestimated effect, but the effect size (ES) was moderate (ES = 0.39) at the 4-6-week follow-up. Although there were no significant differences in the TIC Provider Survey, K6, or Japanese Burnout Scale, a significant effect of the intervention was observed in the Japanese Psychological Safety Scale. A per-protocol analysis, which compared the 30 intervention group participants who had watched all four videos to the control group, showed that the ES (= 0.48) was larger for the ARTIC-35 than for the ITT. CONCLUSION: The intervention led to moderate improvement in attitudes related to TIC, psychological safety, and burnout.