Background The Big 5 personality traits (Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism) are considered relatively stable characteristics that shape human behavior and experience. While research shows these traits can naturally change over time or through sustained effort, there are currently no medical interventions specifically designed to alter them. Current psychiatric and psychological interventions primarily focus on treating specific conditions rather than fundamentally altering personality traits.

This market will resolve YES if before January 1, 2030:

• A medical intervention (drug, procedure, or other treatment, including behavioral therapy) becomes available that

• Has been demonstrated in peer-reviewed research (or some other epistemologically reliable manner) to reliably alter any of the Big 5 personality traits among willing participants

• The effect size of the treatment should be sufficient to take someone from at least the 80th to the 20th percentile (or vice versa) for any trait, as those percentiles would be roughly characterized among the American population as of 2025

• Shows statistically significant changes in personality measures that persist for at least 3 months

The market will resolve NO if no such intervention meets all these criteria by January 1, 2030.