The personality functioning of individuals with a chronic illness

Differences between patients and controls. Our first objective was to explore differences in

Big Five personality traits between individuals with and without a chronic illness, and to relate these traits to various generic and illness-specific outcomes. Some researchers have described chronic illness as a biographical disruption (Bury, 1982; Williams, 2000), as it may heighten one’s awareness of the body, challenge previously held beliefs about the self, impact social relationships, and alter patients’ plans for the future (Charmaz & Rosenfeld, 2010). Despite the hypothesized impact of chronic illness on the self, few studies to date have examined whether there are systematic differences between individuals with and without a chronic illness in terms of their personality. The present doctoral project was the first to examine such differences in individuals with congenital heart disease and Type 1 diabetes. Although differences between patients and controls were generally small, some interesting findings were uncovered.

First, adolescents with congenital heart disease were found to be somewhat less extraverted as compared to healthy controls. In Chapter 8, several possible explanations were forwarded. As activity level constitutes a central feature of extraversion (Costa & McCrae, 1992), patients’ lower levels of extraversion might be partially explained by their lower activity level, resulting from the physical complaints accompanying their illness (e.g., dyspnea, fatigue, shortness of breath). Similarly, positive affectivity is generally considered one of the central features of extraversion (Costa & McCrae, 1992). Possibly, adolescents with congenital heart disease experience less positive affect, having to deal with the worries and challenges of their illness, further lowering their extraversion scores. Finally, the process of normalization, which refers to patients’ struggle with themselves and their environment to be accepted as ‘normal’ (Claessens et al., 2005), may shed light on patients’ lower extraversion scores. From this point of view, an extraverted personality might be less warranted for patients with congenital heart disease who do not want to stand out and just want to be like everybody else (Rigby & Huebner, 2005).

Second, emerging and young adults with Type 1 diabetes were found to be less extraverted and emotionally stable as compared to healthy controls, partially replicating the findings obtained in adolescents with congenital heart disease. As discussed above, activity level constitutes a central feature of extraversion (Costa & McCrae, 1992). Given that prior research has shown that individuals with Type

1 diabetes experience greater fatigue as compared to healthy controls (Varni et al., 2009), patients’ lower extraversion scores might be partially explained by their lower energy levels. Furthermore, patients’ lower levels of emotional stability are in line with prior research pointing to increased prevalence rates of depression among individuals with Type 1 diabetes (Gendelman et al., 2009). As detailed in Chapter 2, we also found that mean-level differences in Big Five personality traits differed for men and women and patients with a shorter versus longer illness duration. More specifically, men with diabetes reported higher levels of agreeableness as compared to healthy men, whereas no such differences in agreeableness were found between women with and without diabetes. We argued that men with diabetes might have learned to adopt a more dependent role and to rely on others more strongly as compared to healthy men, as diabetes management requires close cooperation with parents and healthcare professionals (Tamres et al., 2002). Finally, only patients with a longer illness duration reported heightened agreeableness scores as compared to healthy controls. Individuals diagnosed with diabetes for a longer time might have learned to accept their illness as part of the self, resulting in stronger diabetes integration and even personal growth (Linley & Joseph, 2004; Sparud-Lundin et al., 2010).

In sum, our findings point to normalcy, rather than deviance, in patients’ personality functioning, given the few and relatively small differences observed. As expected, differences between patients and controls were more pronounced in individuals with Type 1 diabetes, given that diabetes generally has a greater impact on daily life as compared to (the mild to moderate variants of) congenital heart disease.

Associations between personality and adjustment. Personality traits have been proven

valuable predictors of various indicators of adjustment in both community and patient samples (Klimstra et al., 2010a; Van De Ven & Engels, 2011). The present doctoral project extends these prior studies in several ways. First, as detailed in Chapter 8, we found all Big Five personality traits (with the exception of openness) to be related to the quality of life and perceived health of adolescents with congenital heart disease – above and beyond the effects of sex, age, and the complexity of the heart defect. In line with prior research in other patient samples, emotional stability turned out to be the strongest predictor of these outcomes (De Clercq et al., 2004; Van De Ven & Engels, 2011). To the best of our knowledge, this is the first study to date linking the Big Five personality traits to the adjustment of individuals with congenital heart disease. In a second study outlined in Chapter 9, a typological approach to personality was adopted, given that several researchers have stressed the importance of taking into account both personality traits and types for obtaining a differentiated view on the associations between personality and adjustment (Chapman & Goldberg, 2011). Three personality types emerged in our sample of adolescents with congenital heart disease: Resilients, Undercontrollers, and Overcontrollers. Our typology closely resembles typologies obtained in previous community samples, with Resilients having high scores on virtually all Big Five traits, Undercontrollers scoring low on conscientiousness and agreeableness, and Overcontrollers scoring low on emotional stability and extraversion, and relatively

high on agreeableness and conscientiousness (Asendorpf et al., 2001; Chapman & Goldberg, 2011; Meeus et al., 2011; Robins et al., 1996; Scholte et al., 2005). Substantial differences in depressive symptoms, loneliness, and generic and illness-specific domains of health were observed among these three personality types, with both Over- and Undercontrollers showing poorer outcomes.

Second, as detailed in Chapter 3, important associations were uncovered between several of the Big Five personality traits and illness-specific distress in emerging and young adults with Type 1 diabetes – above and beyond the effects of sex, age, and illness duration. More specifically, higher levels of agreeableness, conscientiousness, and emotional stability were associated with lower levels of diabetes-specific distress. The finding that extraversion was not related to patients’ adjustment may reflect the difficult balance that patients face between social or peer integration on the one hand and treatment adherence on the other hand (Drew et al., 2010; Helgeson et al., 2009b). These findings further add to the current literature stressing the role of the Big Five personality traits in understanding treatment adherence (Skinner et al., 2002; Waller et al., 2013; Wheeler et al., 2012), glycemic control (Lane et al., 2000; Vollrath et al., 2007; Waller et al., 2013), and illness-specific distress (Taylor et al., 2003) in individuals with Type 1 and Type 2 diabetes.

Third, as outlined in Chapter 4, we uncovered bidirectional associations between personality and several important illness-specific outcomes in adolescents with Type 1 diabetes, using a three-wave longitudinal study design. Previous studies have been mainly cross-sectional in nature, precluding the making of sound conclusions about the directionality of effects. In line with the predisposition model (Tackett, 2006), certain personality traits were found to increase the risk of experiencing diabetes-related problems. More specifically, lower levels of conscientiousness were associated with poorer treatment adherence and glycemic control one year later, whereas higher levels of extraversion predicted poorer treatment adherence over time (Skinner et al., 2002; Vollrath et al., 2007; Waller et al., 2013; Wheeler et al., 2012). Furthermore, lower levels of emotional stability predicted a relative increase in diabetes- specific distress one year later (Taylor et al., 2003). However, in line with the scar model of personality (Tackett, 2006), we also found that diabetes-related problems may lead to relative changes in a patient’s personality. More specifically, poorer treatment adherence predicted a relative decrease in conscientiousness one year later. In addition, higher levels of diabetes-specific distress predicted a relative decrease in emotional stability over time. Finally, poorer treatment adherence and higher levels of distress were associated with relative decreases in agreeableness one year later. Hence, these findings further support the idea that changes in an individual’s personality can be triggered by changing roles, life events, and/or daily challenges (Jeronimus et al., 2014; Shiner et al., 2017; Specht et al., 2011).

In sum, the present doctoral project demonstrated that the Big Five personality traits constitute a valuable framework when examining linkages between personality and adjustment to chronic illness.