This thesis sought to investigate the relationships between treatment delays in bipolar disorder (BD) and cognitive impairments which characterize the disorder, measured both objectively and...Show moreThis thesis sought to investigate the relationships between treatment delays in bipolar disorder (BD) and cognitive impairments which characterize the disorder, measured both objectively and subjectively. Previous studies have established that a long delay occurs between the onset of mood symptoms in BD and the first form of treatment received, estimates ranging between 6 and 11 years. Cognitive impairments in the domains of executive functions, processing speed and memory were found to persist in BD patients even during euthymia. Such cognitive impairments burden BD patients, prevent them from regaining an appropriate level of general functioning and diminish their quality of life. Thus, in order to determine whether treatment delay impacts the cognitive impairments present in BD, 69 participants were followed over the course of one year, at three different time points. The participants took part in clinical interviews, and then were asked to complete multiple measures, such as the YMRS, the QIDS, four WAIS subscales (Block Design, Arithmetic, Information and Digit symbol), and the Cognition subscale of the WHODAS. The average treatment delay found in the current sample was 14.53 years. The results of the current study suggest that longer treatment delays did not significantly predict worse cognitive functioning in BD patients, either when measured subjectively, or when measured objectively.Show less
This study aims to investigate relative age within primary school grades as a potential influential factor of perceived ADHD symptoms. It examines whether relatively younger pupils show more ADHD...Show moreThis study aims to investigate relative age within primary school grades as a potential influential factor of perceived ADHD symptoms. It examines whether relatively younger pupils show more ADHD symptoms than their classmates. The study is of cross-sectional design, using data of primary school children throughout the Netherlands. Participating children are in the age range of four to twelve years old, N = 168. To measure ADHD symptoms, the SNAP-IV (18) has been filled out by parents of the participating children. Relative age serves as the main predictor of this study. Simple linear regressions have been run on relative age (predictor) and ADHD symptoms (dependent). Analyses showed that relative age is no predictor of ADHD symptoms, implying that relative age is no influential factor in perceived ADHD symptoms. However, data screening pointed out that the sample of the current study might not be representative for the general population. Furthermore, the current research design worked with parental observations of ADHD symptoms, and not official ADHD diagnoses. Whether a child has had an ADHD diagnosis was unknown during this study. Incorporating this information in future research could potentially lead to a better understanding of the topic. All in all, the results of this study must be interpreted with care and future research is needed to (dis)prove the relation between relative age and ADHD symptoms.Show less
In an educational setting, every individual may not have equal access to opportunities (such as educational or financial resources) or outcomes (such as grades or evaluations), which could create a...Show moreIn an educational setting, every individual may not have equal access to opportunities (such as educational or financial resources) or outcomes (such as grades or evaluations), which could create a sense of inequality in the individual. Individuals may then attribute these inequalities to their personal efforts and abilities or to their circumstances. Past studies have focused on associations between inequalities (such as social or gender inequality) and educational aspirations (e.g., Guyon & Huillery, 2017; Chen et al., 2022). The present study assesses the main effects of perceived inequality and the attribution of outcomes to internal or external factors (also known as locus of control) on educational aspirations. The study also assesses whether the academic locus of control significantly moderates the impact of perceived inequality on educational aspirations. Utilizing a 1 (continuous measure of academic locus of control) x 3 (inequality: control vs. perception of inequality of outcome vs perception of inequality of opportunity) study design, participants’ aspiration scores were assessed. The participants included N= 190 students enrolled in an undergraduate program. The results from a moderated multiple regression analysis indicated that perceived inequality did not significantly affect educational aspirations. Academic locus of control significantly positively affected aspirations. Academic locus of control also has a significant moderating effect on the impact of inequality. Specifically simple effects analysis indicated that perceived inequality has a significant positive effect on educational aspirations when there is an external locus of control. The study provides an understanding that inequality in an educational context may not impact every individual in the same manner and may differ according to specific factors (such as locus of control).Show less
The present study aimed to examine the way depressed adolescents experience their stressful life events, alongside their perceptions of parental support towards them. There was a sample of 115...Show moreThe present study aimed to examine the way depressed adolescents experience their stressful life events, alongside their perceptions of parental support towards them. There was a sample of 115 adolescents, and their parents (n = 214), including a group of depressed and a group of healthy control adolescents. Each adolescent was asked to write down two stressful events from his/her past and code the intensity of these events. After that, they were asked to discuss these events with their parents, and answer to three questions of the Parental Bonding (PB) questionnaire. Researchers also coded the intensity of the events. For our first hypothesis we conducted a multiple regression analysis to investigate whether depression constitutes a moderator variable between the adolescents’ codes of intensity towards their events and the researchers’ codes. For the second hypothesis we ran one-way ANCOVA to examine if there were any differences between the two groups in PB answers. Depression did not seem to moderate the relationship between the adolescents’ and the researchers’ intensity codes. However, separately, the researchers’ codes and the condition of the adolescents, depressed or not, proved to have statistically significant and positive main effects on the way the adolescents experienced their events. At the same time, the two groups also exhibited statistically significant differences on the PB. Considering these results, it is imperative to highlight the importance of including familial factors and the cultivation of resilience and coping skills towards stress into the intervention and prevention programs that address the adolescent depression.Show less
Background. Parenting plays an important role in the development of adolescent’s emotion regulation (ER). Parental psychological control (PC) is negatively and parental autonomy support (AS) is...Show moreBackground. Parenting plays an important role in the development of adolescent’s emotion regulation (ER). Parental psychological control (PC) is negatively and parental autonomy support (AS) is positively linked to adolescent ER. Impaired ER has been linked to internalizing- and externalizing problems. Parenting is usually examined trough observation or trough self-report methods, but these methods are not interchangeable. Research question. Is adolescent-perceived or observed parenting more important for ER in adolescents, while controlling for depression? Method. In this cross-sectional and multi-method study, 35 depressed and 80 control adolescents (11-17 years) reported on perceived parental PC and AS using the Parental Bonding Inventory and their own behavioral ER using the Children's Emotion Management Scale. Parental PC and AS was observed and scored on the Problem-solving Interaction task. A multiple regression analysis was used. Results. Depressed adolescents showed significantly lower adaptive ER. There were no significant results for adolescent-perceived and observed PC and AS in relation to ER. For the interaction effect of group status with autonomy support, parental support, and ER, no significant results were found. A trend effect was found for the moderating effect between depression and adolescent-perceived PC. Conclusions. Depressed adolescents showed significantly lower adaptive ER, demonstrating the need for ER focused interventions. For teens in middle adolescence, PC and AS parenting did not have a significant effect on their ER. Lastly, when depressed adolescents experienced their parents as more psychologically controlling, they had more difficulty with their ER, highlighting the potential benefit of cognitive behavioral therapy.Show less
Transparency is crucial in psychology research. Recent exposure of poor research practices has contributed to the faltering reputation of research in social sciences. Efforts are being made to...Show moreTransparency is crucial in psychology research. Recent exposure of poor research practices has contributed to the faltering reputation of research in social sciences. Efforts are being made to enhance research transparency through article templates such as registered reports (evaluating and approving preregistered proposals before data collection, Nosek & Lakens, 2014) and verification reports (reanalyzing the original dataset of a study with the intention of reproducing the initial findings and/or testing their robustness, Schiller et al., 2020). However, these article templates can sometimes contribute to a toxic atmosphere wherein researchers argue back and forth instead of collaborating and corresponding with each other. This thesis introduces a new template emphasizing productive communication between the authors of an original study and a second research team that performs the reproductions and/or robustness checks. Based on two studies (the study of Bradshaw et al. (2020) on the interhemispheric deficit theory of dyslexia, where the result was found not to be significant, and the study of Wilks et al. (2021) on the developmental trajectory of speciesism, where the result was found to be significant), this thesis illustrates the application of this template in the context of a multiverse analysis. . The aim of a multiverse analysis is to illustrate how raw data yield multiple datasets processed differently, resulting in various statistical outcomes. This approach allows researchers to explore a range of statistical results instead of analysing just one dataset (Steegen et al., 2016). In the thesis, the corresponding authors of the selected studies were approached to solicit feedback at different stages of the multiverse analyses. Central to this approach is the opportunity for the original authors to offer feedback on the ongoing analyses at any stage, to keep them involved in the process. Both corresponding authors were willing to address questions and, in addition, provided feedback at times when it was requested. Ultimately, two multiverse analyses were conducted. The analysis on the study of Bradshaw et al. (2020) yielded some significant results, while the analysis on the study of Wilks et al. (2021) confirmed the significant results found in their research. This template encourages corresponding authors to actively engage and share their viewpoints. In conclusion, the two case studies show that clear communication and early outreach can create a positive environment focused on improving research transparency and quality.Show less
In recent years, a lack of reproducibility in science has come to light. One of the causes of this lack of reproducibility is the use of questionable research practices (QRPs). P-hacking is one of...Show moreIn recent years, a lack of reproducibility in science has come to light. One of the causes of this lack of reproducibility is the use of questionable research practices (QRPs). P-hacking is one of these QRPs and consists of making impromptu data analytic choices, resulting in a biased significant p-value. The practice of blind analysis could be a viable option to tackle p-hacking. This thesis introduces a new categorization of blind analysis-methods: label blinding, noise blinding and coefficient blinding. Each of these categories has its own implications when it comes to the data analysis. Label blinding allows a researcher to check assumptions with the blinded data, but does not hide the actual p-values. Noise blinding prevents a researcher from checking assumptions with the blinded data, but hides the actual p¬-values. Coefficient blinding allows a researcher to check assumptions and hides the actual p-values, but requires a researcher to specify the model they are going to fit beforehand. Three case studies with simulated data illustrate what the plots and tests used for assumption checks look like for a method from each blind analysis category, as well as what the test statistics might look like. When using a label blinding method while conducting a two-way ANOVA, we are able to check the assumptions of a two-way ANOVA, but our results are not hidden, leaving an opening for p-hacking. When using a noise blinding method while conducting a two sample t-test, we are unable to check the assumptions of a two sample t-test, but our test results are hidden. When using a coefficient blinding method while conducting a linear regression analysis, we are able to check the assumptions of a linear regression and our test results are hidden. Not every blind analysis method is applicable to every dataset or data analysis. More research is needed to explore what blind analysis methods are applicable to which tests. Additionally, guidelines for the practical implementation of blind analysis should be specified.Show less
How does option Self-Generation under pressure affect choice satisfaction? Being linked to pre-existing preferences, Self-Generated options should be evaluated more positively, leading to higher...Show moreHow does option Self-Generation under pressure affect choice satisfaction? Being linked to pre-existing preferences, Self-Generated options should be evaluated more positively, leading to higher satisfaction compared to forced-choice settings; by adding a time limit, the number of generated options should decrease, once again reducing satisfaction. This 2 factor within-subject study explored the relationship between the number of options generated by participants and their choice satisfaction. A causal relationship was tested by adding a time limit to half of the questions answered by each participant. Results showed that, under time pressure, participants produced less options and were less satisfied with their choices. In the unlimited time condition, there was no relationship between number of options and satisfaction, while under time pressure people who generated more options also appeared to be slightly more satisfied with their chosen one. Possible explanations of these results are discussed, and avenues for future research are proposed.Show less
Human-induced global warming drives climate extremes across the entire globe. Thus, people need to understand the consequences of already accumulated CO2, and why reaching the net-zero CO2...Show moreHuman-induced global warming drives climate extremes across the entire globe. Thus, people need to understand the consequences of already accumulated CO2, and why reaching the net-zero CO2 emissions has to be achieved as soon as possible. A communication tool that has power to spread the environmental awareness is data visualisation. The current research aims to find empirical evidence for the effects of three design guidelines (shade, annotations, animation) applied to carbon emissions scenario figures on following outcome measures: climate change risk perception, climate beliefs, climate policy support and real-world action. By testing different ways of visualising the carbon emission figures, we investigated how best to visualise data to convey the message concerning the urgency of taking a climate action due to cumulative impact of CO2. We expected people exposed to visualisations including the most cognitive cues (e.g. annotations) to score highest on the outcome measures. The final sample consisted of 314 non-climate scientists, who were randomly assigned to eight experimental groups and one control group. Our results did not show any effects of the chosen design techniques on any of the outcome measures. The main limitation of this study is a small and homogenous sample. We also concluded that there is some vagueness in the literature concerning how data visualisation design guidelines should be applied. Future research should focus on specifying the data visualisation guidelines and their application, as well as investigating user-cantered and transdisciplinary approaches to improve climate data communication to all types of audiences.Show less
Major Depressive Disorder (MDD) is a significant contributor to global disability, projected to emerge as the leading cause of disability by 2030. While Antidepressants (ADTs) are a prevalent...Show moreMajor Depressive Disorder (MDD) is a significant contributor to global disability, projected to emerge as the leading cause of disability by 2030. While Antidepressants (ADTs) are a prevalent treatment option for MDD, their efficacy is constrained by low remission rates and undesirable side effects, prompting exploration of alternatives. In the last decade, the efficacy of nutraceuticals in MDD treatment has gained attention. However, there is a gap in research regarding direct comparison between the dropout rates in trials investigating the effect of ADTs and nutraceuticals on MDD. This study conducted a comprehensive comparison of efficacy and dropout rates among 17 types of ADTs and 3 types of nutraceuticals. Data were derived from RCTs included in the most recent meta-analyses on this subject. Due to a lack of previous studies on the dropout comparison of ADTs and nutraceuticals, no predictions were made in that regard. However, it was hypothesized that higher dropout rates would be associated with better treatment outcomes. The findings indicate that Nutraceuticals were more effective (Cohen’s d = -1.96, CI: -3.40 to -.53) in MDD treatment compared to ADTs (Cohen’s d = -.35, CI: -.39 to -.31). There were no significant differences in dropout rates between ADTs and nutraceuticals, except within control groups, where nutraceuticals demonstrated lower dropout rates (M =.13) compared to ADTs (M =.28). Furthermore, no relationship between dropout rates and treatment outcomes was observed, except within the ADTs control group where higher dropout rates corresponded to lower treatment outcomes (t (1,144) = -2.91, p = .004). This study shows the comparative efficacy and dropout dynamics of ADTs and nutraceuticals in the treatment of MDD.Show less
The present study experimentally investigated how perceptions of educational inequality impact students' aspirations and the moderating role of locus of control in the relationship between the two....Show moreThe present study experimentally investigated how perceptions of educational inequality impact students' aspirations and the moderating role of locus of control in the relationship between the two. Drawing on prior research, we hypothesised that educational aspirations would be negatively affected by educational inequality of both outcomes and opportunities, whereas it would be positively influenced by internal locus of control. Moreover, we expected locus of control to play a moderating role in the relationship between perceived inequality and aspirations, mitigating the adverse impact of inequality on the latter. Finally, based on previous findings, we expected the impact of perceived inequality of opportunities on aspirations to be comparatively weaker for students with internal academic locus of control when contrasted with perceived inequality of outcomes. A sample of 190 U.S. college students were randomly assigned to watch one of three educational inequality manipulation videos (i.e. opportunities, outcomes, and control). They were then given a questionnaire which assessed their perceptions of inequality, their academic locus of control and their educational aspirations. Only one of our hypotheses was supported by our results. While our findings align with existing evidence that internal locus of control positively affects educational aspirations, there was no main effect of perceived inequality on students’ goals. Notably, our study suggests that higher perceptions of inequality may have motivating effects, which, however, appear exclusive to students with an external locus of control. Given these unexpected findings, further research is warranted for a deeper understanding of the psychological dynamics behind students’ goal-setting processes.Show less
Background: Suicide is a prevalent phenomenon among college students. Studies pointed out that international students in Western countries are more vulnerable for mental health problems and...Show moreBackground: Suicide is a prevalent phenomenon among college students. Studies pointed out that international students in Western countries are more vulnerable for mental health problems and suicidal ideation than domestic students. Aim: This study aimed to conduct a comparative analysis of suicidal ideation between international and domestic students in the Netherlands; to broaden our understanding of the social determinants of suicidal ideation among college students; and to test a macro-micro integrated path model that could predict suicidal ideation among college students. Method: A mixed method strategy (explanatory sequential QUAN + QUAL design) was used among N = 198 domestic and international college students in the Netherlands. Cross- sectional data from questionnaires were gathered and analyzed. A comparative analysis was conducted among domestic and international students. In addition, three mediation models tested the pathways and effects of financial stress, perceived ethnic discrimination, subjective social status, and perceived burdensomeness. These mediations were also tested in an integrated pathway model. Afterward, N = 6 participants were interviewed to explain inconsistent results and to understand how students experience and reflect upon their suicidal ideation in relation to their subjective social status. Quantitative and qualitative data were finally integrated. Results: International students scored higher on suicidal ideation, financial stress, and perceived ethnic discrimination. Moreover, subjective social status and perceived burdensomeness mediated the relationship between perceived ethnic discrimination and suicidal ideation. Although family income was related to subjective social status and suicidal ideation, financial stress showed no significant correlation with the latter. The pathway model showed a good fit, but not all paths were significant. Qualitative results revealed two themes: self-image and social opportunities. Conclusion: International students in the Netherlands faced more suicidal ideation, financial stress and perceive more ethnic discrimination. Although financial stress was not linked to suicidality in this study, the importance of socio-economic factors is highlighted as family income was correlated to suicidal ideation. Lastly, while there was evidence for a relation between subjective social status and suicidal ideation, qualitative results indicated that higher subjective status might lead to risk factors for suicidal ideation as well.Show less
Abstract Introduction: Perceived parental warmth (PW) is positively associated with self-esteem, and negatively with rumination and depressive symptoms in adolescents. (Daily) Self-esteem, and ...Show moreAbstract Introduction: Perceived parental warmth (PW) is positively associated with self-esteem, and negatively with rumination and depressive symptoms in adolescents. (Daily) Self-esteem, and (daily) rumination potentially mediate the association between daily perceived PW and adolescent’s depressive symptoms. Objective: The aim of this study was to examine whether (daily) self-esteem and (daily) rumination mediate in the association between daily perceived PW and adolescent’s depressive symptoms; combining both questionnaire data and ecological momentary assessment (EMA). Methods: This study was based on data from the Relations and Emotions in Parent Adolescent Interaction Research (RE-PAIR). The sample consisted of 80 healthy control and 33 adolescents with depressive symptoms (n = 113). Participants filled out questionnaires examining depressive symptoms, self-esteem, and rumination, and participated in EMA (14 consecutive days) examining daily PW, daily self-esteem, and daily rumination. Results: Findings from the questionnaire data showed self-esteem and rumination did not mediate the association between daily perceived PW and depressive symptoms. Findings from the EMA showed daily self-esteem and daily rumination fully mediated the association between daily perceived PW and depressive symptoms. Discussion: Findings indicated daily perceived PW was negatively associated with adolescent’s depressive symptom levels, and that levels of daily self-esteem and levels of daily rumination fully mediated this association. The questionnaire data of self-esteem and rumination did not mediate in the association between daily perceived PW and adolescent’s depressive symptom levels. Similarities and discrepancies between questionnaire data and EMA are addressed in the discussion. Findings in the light of limitations are discussed. Interventions to promote daily PW might be beneficial for adolescents with depressive symptoms. Future studies could elucidate the effects of these interventions.Show less
Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a rare, autosomal dominantly inherited small vessel disease, caused by TREX1 gene mutations. Vascular...Show moreRetinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a rare, autosomal dominantly inherited small vessel disease, caused by TREX1 gene mutations. Vascular retinopathy, focal neurological deficits, cognitive deterioration, and several other systemic features are indicative of RVCL-S. Moreover, the disease is characterized by white matter hyperintensities, which could contribute to cognitive deterioration observed in RVCL-S patients. Especially the cognitive domains working memory and processing speed are impaired during neuropsychological assessment, even though the underlying mechanisms remain unknown. Consequently, this thesis examined whether TREX1 mutation carriers (n = 23) perform cognitively poorer on working memory and processing speed tasks compared to healthy controls (n = 47). In addition, it has been examined whether white matter hyperintensities, according to the Fazekas scale, are predictive of cognitive functioning in TREX1 mutation carriers. Contrary to the pre-defined hypotheses, TREX1 mutation carriers did not perform significantly poorer on the Digit Span test, the Letter Span test, and the Trail Making Test-B, compared to the control group. It can therefore not be concluded that working memory and processing speed performance are affected in TREX1 mutation carriers. Future studies are advised to use more sensitive neuropsychological tests to detect subtle cognitive changes.Show less
This research explores the interplay between social media usage, offline and online interactions, perceived social support, and depression levels among university students. Analyzing data from 430...Show moreThis research explores the interplay between social media usage, offline and online interactions, perceived social support, and depression levels among university students. Analyzing data from 430 participants, this cross-sectional study leverages the Patient Health Questionnaire-9 (PHQ-9) to assess depression symptoms and employs both multivariate and univariate linear regression analyses, as well as MANOVA and ANOVA tests, to understand the connections between online/offline social interactions, perceived social support, and depression. Key findings indicate a significant relationship between the level of perceived social support (β = -0.49, p < .001) and frequency of online interactions (β = 0.43, p < .05) with depression levels. Notably, individuals reporting higher levels of perceived social support tend to exhibit lower depression levels, while those with frequent online interactions often show higher depression levels. The study also identifies marked gender differences in social media use and depression, with females showing greater susceptibility. These results underscore a nuanced relationship between active/passive social media engagement, gender, and mental health. The research emphasizes the need for mental health strategies that consider individual differences, particularly focusing on the quality of social support and patterns of online engagement, to effectively address mental health concerns in young adults.Show less
