PERSONALITY AND HEALTH 125Type D personalitySimilar to type A, type D personality is a risk factor for coronary heart disease.
The type D, or distressed, personality describes individuals who experience high
levels of negative emotions (negative affectivity) and inhibit the expression of these
negative emotions in social interactions (social inhibition). The concept was
introduced by Johan Denollet, of Tilburg University in the Netherlands.
Type D personality can be assessed by a self-report questionnaire containing
items that tap negative affectivity (e.g. ‘I often make a fuss about unimportant
things’ or ‘I often feel unhappy’) and social inhibition (e.g. ‘I often feel inhibited in
social interactions’ or ‘I find it hard to start a conversation’). A type D individual
would be someone who scores highly on both of these dimensions. This is
important because previous research has shown negative affectivity or neuroticism
to be related to various negative health outcomes.
Denollet and colleagues have shown the type D personality to be a risk factor
for adverse health outcomes in cardiac patients. So, for example, Denollet et al.
(1996) assessed type D in a sample of 286 cardiac patients who were receiving
treatment. Approximately one-third of the sample were classified as type D.
Approximately 8 years later, the patients were followed up. Among those classified
as type D a total of 27 per cent had died compared with a total of 7 per cent of the
rest of the sample. A majority of the deaths were due to heart disease or stroke.
This translated into an odds ratio of almost four (i.e. being four times more likely
to die if classified as type D compared to those not classified as type D). These
effects were replicated in several studies. However, a meta-analysis including
more recent studies suggested this was an overestimate and gave an odds ratio of
2.28 (Grande, Romppel and Barth, 2012). More recent studies have often found
smaller effects, a pattern seen in research in other areas discussed above and have
questioned the definition of the construct (see Ferguson et al., 2009).
The explanation for the relationship between type D and risk of death is not
entirely clear. Those with type D personalities appear to have more highly activated
immune systems and more inflammation (perhaps indicating more damage to
blood vessels in the heart and throughout the body). They also show greater
increases in blood pressure in reactions to stress. Recent research has suggested
that type D individuals engage in fewer health behaviours and experience lower
levels of social support and that these effects remain after controlling for
neuroticism (Williams et al., 2008).FOCUS 6.3