[citation needed] The type D personality was defined in the 1990s, describing individuals who experience feelings of negativity, depression, anxiety, stress, chronic anger, and loneliness.
Generally speaking, social situations tend to make type D individuals feel inhibited, tense, uncomfortable, and insecure.
A wide variety of health risks are associated with type D personalities, primarily due to the fact that they seem to lead to a more highly activated immune system and therefore, more inflammation.
[3] According to Dr. Denollet, what most likely links poor health outcomes to the type D personality subtype is the distinctly high level of stress associated with it.
High levels of cortisol are thought to be the mediating factor in the association between this personality type and the increased risk for coronary heart disease.
The correlation between emotional suppression and cardiovascular complications has been observed in numerous different studies, including one that involved patients undergoing cardiac rehabilitation.
Patients scoring high on negative affectivity and social inhibition (the two dimensions of the type D personality subtype) were found to be seven times more likely to suffer sudden cardiac death.