Michèle Nuijten, Jelte M. Wicherts and I are looking for a PhD candidate to assess the statistical validity of psychological intervention studies. The candidate will apply a wide range of state-of-the-art meta-scientific techniques to studies in the domain of medical and clinical psychology. The project can have immediate impact by proposing concrete ways to improve practices in psychological intervention studies. This interdisciplinary PhD project lies at the intersection of methodology and statistics on the one hand, and medical and clinical psychology on the other hand. Apply before June 1: https://tiu.nu/21539
On Friday 27 January I was awarded my PhD degree with a cum laude distinction at Tilburg University after defending my thesis: “Medical Psychometrics: A psychometric evaluation of Type D personality and its predictive value in medical research”. The digital version of the thesis can be found here.
It was an unforgettable day! Many thanks to my promotor Prof. dr. Jelte M. Wicherts, my former promotor the late Prof. dr. Johan Denollet, my co-promotors Dr. Wilco Emons and Dr. Nina Kupper, my paranymphs Dr. Tom IJdema and Dr. Robbie van Aert, and the members of the doctoral committee: Dr. Stefanie Duijndam, Prof. dr. Brian Hughes, Prof. dr. Timothy Smith, Dr. Mathilde Verdam and Prof. dr. Jeroen Vermunt.
Type D personality, a joint tendency toward negative affectivity (NA) and social inhibition (SI), has been linked to adverse events in patients with heart disease, though with inconsistent findings. In previous work we have shown that traditional methods used to analyse the link between Type D personality and outcome measures can lead to inaccurate conclusions and that half of the published Type D effects are likely merely effects of only NA or SI.
In this new publication in Psychosomatic Medicine, we have contacted Type D researchers across the world with the request if they want to share their data investigating the link between Type D personality and adverse outcome in cardiovascular disease. Our aim was to combine these datasets and analyse them with a statistical method that does not suffer from the limitations of traditional methods.
In this comprehensive meta-analysis of 19 prospective cohort studies, encompassing over 11,000 patients we found that Type D personality significantly predicts major adverse cardiac events and any adverse event in patients with cardiovascular disease. However, the impact on all-cause mortality, cardiac mortality, and myocardial infarction appears negligible.
Interestingly, the study highlights that the effects of Type D personality are more pronounced in patients with coronary artery disease (CAD) compared to those with heart failure (HF). Additionally, negative affectivity alone was found to influence cardiac and all-cause mortality, with a stronger effect observed in male patients.
These insights underscore the importance of considering psychological factors in managing cardiovascular health. As we continue to unravel the complexities of heart disease, understanding the role of personality traits like Type D can pave the way for more personalized and effective treatments.
Have you ever wondered if your personality traits remain the same throughout your life? Recent research delves into this intriguing question by examining the temporal stability of psychological constructs like the two Type D personality traits negative affectivity and social inhibition. These traits are often linked to adverse health outcomes, particularly in cardiac patients. The study highlights the importance of assessing the stability of these traits over time to understand their long-term impact on health.
In our publication in theJournal of Research in Personality, we used longitudinal latent variable models to analyze data from 2,625 cancer survivors over four years. These models help account for measurement errors and the non-normal distribution of questionnaire scores, providing a more accurate picture of personality stability.
The findings suggest that while personality traits like negative affectivity and social inhibition remained stable over time when averaged across all participants, individual changes in negative affectivity over time were found to correlate with similar changes in depression and anxiety, but SI did not show this association.
This research underscores the complexity of personality development and the need for robust statistical methods to study it. Understanding how and why our personality traits change can have significant implications for mental health and well-being.
Together with colleagues I investigated the psychological predictors of the willingness to get a COVID-19 vaccination. Our study was recently published open access in the Journal of Anxiety Disorders. We specifically examined whether fear of COVID-19 predicts vaccination willingness. We followed 938 participants for 14 months and measured their fear for COVID-19 in April 2020 and vaccination willingness was measured in June 2021. Approximately 11% of the participants indicated that they were not willing to get vaccinated. Results of a logistic regression showed that increased fear of COVID-19 predicts vaccination willingness 14 months later, even when controlling for several anxious personality traits, infection control perceptions, risks for loved ones, self-rated health, previous infection, media use, and demographic variables. These results show that fear of COVID-19 is a relevant construct to consider for predicting and possibly influencing vaccination willingness. Nonetheless, sensitivity and specificity of fear of COVID-19 to predict vaccination willingness were quite low and only became slightly better when fear of COVID-19 was measured concurrently. This indicates that other potential factors, such as perceived risks of the vaccines, probably also play a role in explaining vaccination willingness.
My new track Callisto is included on a beautiful ambient compilation released on Nuno dos Santos’ label Something Happening Somewhere. The release is available digitally or on cassette tape: https://sohaso.bandcamp.com/album/somewhere-v
In this new study published in General Hospital Psychiatry, we examined the differences between two methods that are commonly used in the literature to estimate a Type D personality effect. Type D personality, operationalised as high scores on negative affectivity (NA) and social inhibition (SI), has been associated with various medical and psychosocial outcomes. The recent failure to replicate several earlier findings could result from the various methods used to assess the Type D effect. Despite recommendations to analyse the continuous NA and SI scores, a popular approach groups people as having Type D personality or not. This method does not adequately detect a Type D effect as it is also sensitive to main effects of NA or SI only, suggesting the literature contains false positive Type D effects. Here, we systematically assess the extent of this problem. We conducted a systematic review including 44 published studies assessing a Type D effect with both a continuous and dichotomous operationalisation. The dichotomous method showed poor agreement with the continuous Type D effect. Of the 89 significant dichotomous method effects, 37 (41.6%) were Type D effects according to the continuous method. The remaining 52 (58.4%) are therefore likely not Type D effects based on the continuous method, as 42 (47.2%) were main effects of NA or SI only. Half of the published Type D effect according to the dichotomous method may be false positives, with only NA or SI driving the outcome. Our findings suggest that a large part of the Type D literature should be reanalysed to find out whether the results remain unchanged when using the continuous method.
In this new study published in the journal Structural Equation Modeling we focused on three popular methods to model interactions between two constructs containing measurement error in predicting an observed binary outcome: logistic regression using (1) observed scores, (2) factor scores, and (3) Structural Equation Modeling (SEM). It is still unclear how they compare with respect to bias and precision in the estimated interaction when item scores underlying the interaction constructs are skewed and ordinal. In this article, we investigated this issue using both a Monte Carlo simulation and an empirical illustration of the effect of Type D personality on cardiac events. Our results indicated that the logistic regression using SEM performed best in terms of bias and confidence interval coverage, especially at sample sizes of 500 or larger. Although for most methods bias increased when item scores were skewed and ordinal, SEM produced relatively unbiased interaction effect estimates when items were modeled as ordered categorical.
A new studyI published in the journal Personality and Individual Differences is a sequel to my study published in the Journal of Psychosomatic Research, earlier this year. Type D personality has been associated with various medical and psychosocial outcomes. Type D’s underlying personality traits negative affectivity (NA) and social inhibition (SI) are hypothesized to either additively (NA + SI) or synergistically (NA ∗ SI) affect an outcome. As some of the methods used to assess a Type D effect have been criticized in the past, this study aimed to investigate for all commonly used methods their tendency of producing false positive Type D effect. 324,000 datasets were generated using a Monte Carlo Simulation. Each dataset was analyzed using various methods to assess a Type D effect. Each method’s performance was assessed in terms of absolute bias and the percentage of false-positive findings. An online application was developed where readers can easily experiment with this simulation. Our simulation showed that all commonly used methods risk producing false-positive Type D effects. The only method with adequate false-positive rates included the continuous NA and SI main effects, as well as their quadratic effects and their interaction. All commonly used methods to assess a Type D personality effect showed inflated false-positive rates in realistic simulation scenarios. All earlier research based only on these methods should be reconsidered.
I am truly honored to have been awarded the Elsevier & EAPM Young Investigator Award for my recently published article in the Journal of Psychosomatic Research. I would like to thank EAPM and Elsevier for making this award possible. Also many thanks to my supervisors Prof. Dr. Jelte Wicherts and Dr. Nina Kupper for their support and inspiration. Lastly, special thanks to the late Prof. Dr. Johan Denollet, without whom this study would never have taken place. I dedicate this award to him.
