Are we witnessing the decline effect in the Type D personality literature? What can be learned?

Abstract

a b s t r a c t a r t i c l e i n f oAfter an unbroken series of positive, but underpowered studies seemed to demonstrate Type D personality predicting mortality in cardiovascular disease patients, initial claims now appear at least exaggerated and probably false. Larger studies with consistently null findings are accumulating. Conceptual, methodological, and statistical issues can be raised concerning the construction of Type D personality as a categorical variable, whether Type D is sufficiently distinct from other negative affect variables, and if it could be plausibly assumed to predict mortality independent of depressive symptoms and known biomedical factors, including disease severity. The existing literature concerning negative affect and health suggests a low likelihood of discovering a new negative affect variable that independently predicts mortality better than its many rivals. The apparent decline effect in the Type D literature is discussed in terms of the need to reduce the persistence of false positive findings in the psychosomatic medicine literature, even while preserving a context allowing risk-taking and discovery. Recommendations include greater transparency concerning research design and analytic strategy; insistence on replication with larger samples before accepting "discoveries" from small samples; reduced confirmatory bias; and availability of all relevant data. Such changes would take time to implement, face practical difficulties, and run counter to established practices. An interim solution is for readers to maintain a sense of pre-discovery probabilities, to be sensitized to the pervasiveness of the decline effect, and to be skeptical of claims based on findings reaching significance in small-scale studies that have not been independently replicated.© 2012 Elsevier Inc. All rights reserved. IntroductionMany "discoveries" turn out to be exaggerated or simply false across diverse research areas and disciplines. John Ioannidis [1] provoked concern with his demonstration that of the 49 most cited clinical research studies in major journals, replications of 34 had been attempted, and 41% of key findings had been refuted or shown to be substantially diminished. In a subsequent paper [2] he offered evidence that "most claimed research findings are false" and he and others [3-6] have since identified some mechanisms by which discoveries appear in the literature and then undergo a decline or refutation. Claims of breakthrough discoveries frequently arise in small positive studies that would seem to be too underpowered to detect an effect, and the inadequate sample size makes findings all the more attention grabbing.Yet, portrayals in the literature of such "discoveries" ignore the larger context of a strong confirmatory bias in published research papers, with unknown numbers of negative findings not being published and findings being declared discoveries simply because of having achieved an arbitrary level of significance. Moreover, statistically significant findings in small studies are nece...

A Type A and Type D Combined Personality Typology in Essential Hypertension and Acute Coronary Syndrome Patients: Associations with Demographic, Psychological, Clinical, and Lifestyle Indicators

“…Such longitudinal studies would also allow an investigation of the degree to which these clusters interact or transact over time with illness-specific tasks, such as changing lifestyle habits and controlling modifiable risk factors, which are cardinal aspects of CVD prevention and treatment. Moreover, these longitudinal data could also be concentrated to analyse personality data in terms of the interactions of continuous variables because various researchers have raised issues about the validity of conceptualizing personality types as categorical types [66]. Third, additional studies are necessary to assess whether various interventions yield different outcomes for different personality profiles to improve individuals’ self-management of their health condition.…”

“…Furthermore, other issues have been raised concerning the construction of the Type D personality in terms of research design, methodology and statistical aspects: for example, the use of median-split or dichotomized continuous measures on arbitrarily chosen cut-points; the use of cross tabs to select the patients in the high quadrant for negative affectivity and social inhibition levels and compared them to the patients in the other three quadrants; when regression models were used to test multivariate predictions, an abuse of selection by including possible covariates-confounders (and excluding others) depending on the impact of negative affectivity and social inhibition variables; and the flexible extension or contraction of follow-up periods, depending whether Type D personality significantly predicted mortality or other outcomes. All of these aspects could magnify the results related to Type D personality [66]. …”

Depression and Cardiac Disease: Epidemiology, Mechanisms, and Diagnosis

“…Poor outcomes may be exacerbated by the presence of cooccurring anxiety, which is independently associated with recurrent cardiac events and mortality [83] and which has been linked with poor response to treatment for depression [84–86]. Other patients who appear to be at particularly high risk for poor outcomes include those with prominent anhedonia (the inability to experience pleasure) [87–89] and those with type D personality (a personality structure characterized by negative affectivity and social inhibition) [19], though the latter association is controversial [90]. …”

A Critical Analysis of the Assumptions of Type D Personality: Comparing Prediction of Health-Related Variables with the Five Factor Model

“…neuroticism and extraversion) that the measure can be considered unique. This assumption has been criticized in the literature (Coyne & de Voogd, 2012). A meta-analysis (Horwood, Anglim, & Tooley, 2015) found relatively large mean correlations between negative affectivity and neuroticism of r = .74 and between social inhibition and extraversion of r = -.63.…”