Science

Publication Search Results

Now showing 1 - 4 of 4
  • (2013) Grisham, Jessica; Williams, Alishia
    Journal Article
    The aim of the current study was to examine cognitive and psychological factors hypothesized to affect responding to intrusions in obsessive-compulsive disorder (OCD). A group of individuals diagnosed with OCD was compared to a social phobia (SP) group and a nonclinical control group. Participants performed neuropsychological tasks, completed selfreport measures, and engaged in a self-relevant thought suppression task. The OCD group demonstrated worse working memory and response inhibition and had increased intrusions during the suppression task relative to comparison groups. They also reported more distress during the task relative to the nonclinical group, but not the SP group. Regression analyses revealed that beliefs about thought control failures, but not working memory or response inhibition, was associated with increased frequency of intrusions and greater distress during suppression. Findings support cognitive-behavioural models of OCD that emphasize the role of meta-beliefs in explaining the struggle with obsessional thoughts.

  • (2013) Williams, Alishia; Lau, Gloria; Grisham, Jessica
    Journal Article
    Background and Objectives: Thought-action fusion (TAF), or maladaptive cognitions regarding the relationship between mental events and behaviours, has been implicated in the development and maintenance of obsessive-compulsive disorder (OCD). As some religions promote TAF-like appraisals, it has been proposed that religiosity may play a role in the transformation of normally occurring intrusive thoughts into clinically distressing obsessions. No research, however, has experimentally investigated the mediating role of TAF on the relationship between religiosity and OC symptoms. Methods: 85 Christian, Jewish, and Atheist/Agnostic participants were exposed to an experimental thought-induction protocol and reported on their associated levels of distress, guilt, feelings of responsibility, and urge to suppress target intrusions experienced during a 5-minute monitoring period. Participants also completed measures of obsessive-compulsive symptomatology, TAF beliefs, and general psychopathology. Results: Using PROCESS and bootstrapping analyses, a test of the conditional indirect effects of religiosity on obsessive-compulsive symptoms revealed that Christianity moderated the effects of religiosity on moral TAF beliefs, which in turn mediated the relationship between religiosity and obsessive-compulsive symptoms. Furthermore, in the Christian group, moral TAF beliefs mediated the relationship between religiosity and ratings of guilt and responsibility following the experimental protocol. Limitations: The use of university students with moderate levels of religiosity. Conclusions: Collectively the results suggest that obsessional thinking is not attributable to religion per se, but that teachings underlying certain religious doctrines may fuel TAF beliefs that are implicated in the maintenance of OCD.

  • (2010) Williams, Alishia; Moulds, Michelle; Grisham, Jessica; Gay, Philippe; Lang, Tamara; Kandris, Eva; Werner-Seidler, Aliza
    Journal Article
    Study 1 evaluated the psychometric properties of the English version of the Thought Control Ability Questionnaire (TCAQ; Luciano, Algarabel, Tomás, & Martínez, 2005), an index of perceived control over intrusive cognitions. Confirmatory factor analysis in a sample of 720 University students revealed a clear uni-dimensional structure (after removal of items 5, 7, 8, 14, and 25) with high internal consistency (α = .87, 95% CI = [.86, .88]) and test-retest reliability after a six month interval (r = .68). Correlational analyses supported an inverse relationship with measures of depression, anxiety, maladaptive cognitive control strategies, and obsessive–compulsive symptomatology. Study 2 tested the ability of the TCAQ to predict successful cognitive control during an experimental suppression protocol. Results demonstrated that weak thought control ability was predictive of the frequency and associated levels of distress of a target thought while under instruction to suppress. Additionally, weak perceived thought control ability was predictive of increased efforts to suppress the target material. Collectively, results suggest that thought control ability is a measurable individual difference variable and that the TCAQ is a reliable index of perceived cognitive control.

  • (2014) Coupland, Kirsten G; Mellick, George D; Silburn, Peter A; Huang, Yue; Halliday, Glenda; Hallup, Marianne; Woojin, S. Kim; Dobson-Stone, Carol; Kwok, John BJ; Mather, Karen; Armstrong, Nicola J; Sachdev, Perminder; Brodaty, Henry
    Journal Article
    Background: Parkinson's disease (PD) is a neurodegenerative disorder for which environmental factors influence disease risk and may act via an epigenetic mechanism. The microtubule-associated protein tau (MAPT) is a susceptibility gene for idiopathic PD. Methods: Methylation levels were determined by pyrosequencing of bisulfite treated DNA in a leukocyte cohort (358 PD and 1084 controls) and two brain cohorts (Brain1 comprising 69 cerebellum controls, Brain2 comprising 3 brain regions from 28 PD and 12 controls). In vitro assays involved the transfection of methylated promoter-luciferase constructs or treatment with an exogenous micronutrient. Results: In normal leukocytes, MAPT H1/H2 diplotype and gender were predictors of MAPT methylation. Haplotype-specific pyrosequencing confirmed H1 haplotype to have higher methylation than H2 in normal leukocyte and brain tissues. MAPT methylation was negatively associated with MAPT expression in Brain1 cohort and transfected cells. Methylation levels differed between three normal brain regions (Brain2, putamen > cerebellum > anterior cingulate cortex). In PD samples, age at onset was positively associated with MAPT methylation in leukocytes. Moreover, there was hypermethylation in the cerebellum and hypomethylation in the putamen of PD patients compared with controls (Brain2 cohort). Finally, leukocyte methylation status was positively associated with blood Vitamin E levels, the effect being more significant in H2 haplotype carriers; this result was confirmed in cells exposed to 100 μM Vitamin E. Conclusions: The significant effects of gender, diplotype and brain region suggest that hypermethylation of the MAPT is neuroprotective by reducing MAPT expression. Vitamin E effect on MAPT represents a possible gene-environment interaction.