Mathias Allemand

Objective Recent research suggests that personality traits can be changed by psychological interventions. However, it is unclear whether these intended personality changes can be maintained or merely reflect ephemeral shifts. Method The present study reports 1‐year follow‐up effects of a 3‐month digital intervention for personality trait change. Personality traits were measured before the intervention (pretest: N = 1523), directly after the intervention (posttest: n = 554), and 3 months (follow‐up 1: n = 437) and 1 year (follow‐up 2: n = 157) after the end of the intervention. Results Attrition analyses suggest that participants who completed the 1‐year follow‐up were significantly more open to experience ( d = 0.19), less neurotic ( d = 0.20), more agreeable ( d = 0.35) and more conscientious ( d = 0.27) than participants who did not complete the 1‐year follow‐up. Also, until the 1‐year follow‐up, personality trait changes achieved remained stable (for those who wanted to increase in extraversion and conscientiousness) or even changed further in the desired direction (for those who wanted to decrease in neuroticism). Conclusion These results suggest that changes in personality traits due to a targeted intervention are not just ephemeral shifts and can even continue.