1. PERSONALITY AND HEALTH Lecture 6 Yvette Lamb

2. CURRENT ISSUES

3. Current Issues Timothy Smith (2006) outlines several issues that need to be considered when examining relationships between health and personality ◦Assessment of health – subjective versus objective ◦Measurement of personality – psychometric concerns (validity and reliability) ◦Study design – prospective designs versus cross-sectional designs ◦Mechanisms underlying associations – describing relationships versus explaining relationships

4. Health Assessment ◦Studies are most useful if they look at unambiguous outcomes (such as mortality and diseases that have been diagnosed using objective criteria). ◦ Ambiguous outcomes include utilization of health care and self-ratings of health/symptoms. ◦ Ambiguous outcomes (while still important) can make it difficult to ascertain whether personality is associated with health OR only with illness behaviour.

5. Personality Measurement ◦Individual studies often utilise personality tests/scales developed by the authors of that particular study. ◦ These scales frequently lack reliability and validity. ◦ The Big Five model may be useful in bringing order to this proliferation of measures (facets within the broader traits should be considered)

6. Study Design ◦In cross-sectional designs, an association between personality measures (e.g., negative emotionality) and illness could reflect personality contributing to illness ◦However, the association could alternatively reflect reactions to the illness (problem of correlation ≠ causation). The likelihood of this can be reduced by using prospective designs.

7. Underlying Mechanisms ◦Associations are not explanations. ◦While studies often describe potential mechanisms that may underlie associations between personality measures and health, these mediational hypotheses are seldom tested. ◦ Elucidating underlying mechanisms is crucial for research in this area to progress and to have practical applications within healthcare. ◦ Perceived credibility may also rest on research into these mechanisms.

8. Linear Regression The regression line (represented by the equation Ŷ = bX + a ) can be used to predict Y (e.g., cardiovascular health) on the basis of X (e.g., conscientiousness).

9. Mediation Regression Figure taken from N. R. Herr (http://www.nrhpsych.com/mediation/logmed.html) ◦ X = causal variable ◦ M = mediator ◦ Y = outcome ◦ If c’ is non-significant while c was, you have demonstrated complete mediation

11. ◦Example from Hampson et al. (2007) – structural model of direct and indirect influences of childhood personality on adult health status through educational attainment and health behaviours

14. Models taken from T. W. Smith (2006)

15. SPECIAL TOPICS

16. Topics to choose from… ◦ Anorexia Nervosa (Amianto et al., 2011) ◦ Obesity (Sutin et al., 2011) ◦ Alzheimer’s Disease (Duchek et al., 2007) ◦ Wound healing speed (Ebrecht et al., 2004)

17. In your group presentation, discuss… ◦ The background, methodology and key findings of the study ◦ What this study might tell us about the relationship between personality and health – consider the mechanism models of Smith (2006) ◦ Potential applications of this knowledge

18. FUTURE DIRECTIONS

19. Personality in Personalised Medicine ◦ Reading for this week: Boersma, G. L., Benthem, L., van Beek, A. P., van Dijk, G., & Scheurink, A. J. (2011). Personality, a key factor in personalized medicine? European Journal of Pharmacology, 667, 23-25. Chapman, B. P., Roberts, B., & Duberstein. P. (2011). Personality and longevity: Knowns, unknowns and implications for public health and personalized medicine. Journal of Aging Research.