Long-term effects of filmed social contact or internet-based self-study on mental health-related stigma: a 2-year follow-up of a randomised controlled trial

Purpose There is a critical need to clarify the long-term effects of anti-stigma interventions. The study aimed to assess the long-term effects of repeated filmed social contact or internet-based self-study on mental health-related stigma through a randomised controlled trial with 2-year follow-up. Methods We randomly allocated 259 university or college students to a filmed social contact group, an internet-based self-study group, or a control group. The filmed social contact and internet-based self-study groups each received a 30-min initial intervention followed by emailed interventions every 2 months over a 12-month period. The Japanese version of the Reported and Intended Behaviour Scale (RIBS-J) and the Mental Illness and Disorder Understanding Scale (MIDUS) were used to assess behaviour, behavioural intentions (attitudes), and knowledge regarding mental health. Results Of the 259 original participants, 187 completed the 24-month follow-up assessment. Mean scores for the RIBS-J future domain and MIDUS peaked at 1 month after initial intervention. Compared with baseline, at 24-month follow-up, we found a significant difference in RIBS-J future domain scores between the filmed social contact and control groups at 24-month follow-up ( B = 0.95, 95% CI = 0.01,1.90, p = 0.049), while MIDUS scores in the filmed social contact group ( B = − 4.59, 95%CI = − 6.85, − 2.33, p