The Big Five personality traits are powerful predictors of health and longevity. However, few studies have addressed partner effects of personality on health, whereby the personalities of people close to us affect our health. The current study examined the partner effects of Big Five traits on health behaviours, mood, and quality of life in romantic couples. Here, 182 romantic couples (N = 364 participants; Mage = 35.7 years) completed self-report measures of the Big Five (TIPI), health behaviours (GPHB), mood (DASS-21) and quality of life (WHOQOL-BREF). Data were analysed using the Actor-Partner Interdependence Model and showed significant partner effects of conscientiousness on quality of life. No other partner effects of the Big Five were found. These findings suggest that there are specific, focussed associations between health and a romantic partner’s personality.

A recent meta-synthesis indicates that the Big Five traits are moderately associated with overall health, with larger effects for agreeableness, conscientiousness, and neuroticism than either extraversion or openness to experience (Strickhouser, Zell, & Krizan, 2017). Conscientiousness has been consistently shown to have a positive impact on health, predicting positive health behaviours (Bogg & Roberts, 2004), physical health (Sutin, Stephan, & Terracciano, 2018), and increased longevity (Kern & Friedman, 2008). In contrast, neuroticism is associated with poor health outcomes, including all-cause mortality (Ó Súilleabháin, & Hughes, 2018). These intrapersonal effects of the Big Five on health are well established but less research has examined the interpersonal effects of personality on health, whereby the personalities of people close to us affect our health (Zayas, Shoda, & Ayduk, 2002). Zayas et al. outline a personality-in-context framework, which suggests that our thoughts, emotions, and behaviours are the product of the interpersonal system that we are part of, rather than solely the result of our own personality. Roberts, Smith, Jackson, and Edmonds (2009) conducted one of the first studies to demonstrate partner effects of conscientiousness. Nickel, Iveniuk, and Roberts (2017) replicated these results. They found that those with partners with higher levels of conscientiousness reported better subjective health and fewer physical limitations. The authors referred to this effect as compensatory conscientiousness, as partner conscientiousness predicted health outcomes above and beyond the individual’s own level of conscientiousness.