Personality as a moderator of intervention effects: Examining differential susceptibility

Abstract

The aim of the present study was to determine whether Big Five personality traits moderated intervention effects through differential susceptibility for environmental factors. We conducted a randomized controlled trial in which adolescents received either Rock & Water (a universal school based intervention aiming to enhance youth's psychosocial development) or care as usual. Adolescents (N = 1299, Mage = 12.38) reported on the outcomes (i.e., psychological wellbeing, resilience, aggression, and bullying) at four different time points during two years. Parents reported on adolescents' personality at baseline. Adolescents with high levels of Neuroticism and Extraversion, and low levels of Conscientiousness, Openness to experiences, and Agreeableness benefitted most from the intervention. As high levels of Neuroticism, and low levels of Conscientiousness and Openness to experiences are seen as markers of environmental susceptibility, the moderation pattern supported the pathway of differential susceptibility. Particularly adolescents susceptible to environmental factors appear to be able to benefit from an intervention. Knowledge about how less susceptible adolescents can be successfully targeted is eminent to optimize interventions for this group of adolescents.