Thesis (Ph. D.)--Illinois State University, 1998. / Title from title page screen, viewed July 10, 2006. Dissertation Committee: Jeffrey B. Hecht, Paul Baker (co-chairs), Patricia H. Klass, Graham Jones. Includes bibliographical references (leaves 148-154) and abstract. Also available in print.

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Rumination is a well-established risk factor for the onset and maintenance of depression and anxiety and has been identified as a transdiagnostic factor due to its association with multiple forms of psychopathology. A renaissance of psychedelic research shows promise in treating psychopathology with potential for acting on ruminative processes. Despite the growing interest and developments in legality, very few research studies have investigated the psychological consequences of participating in an ayahuasca ceremony in North America. The current study included 30 participants (Mage = 41.03, SD = 7.35; range = 30-59 years; 50.0% women; 76.7% White/Caucasian) who participated in an ayahuasca ceremony at a North American ayahuasca church. Participants were asked to complete seven daily surveys prior to their ceremony (Phase I) and seven daily surveys following their ceremony (Phase II). Multi-level models tested changes in rumination and depression, anxiety, and stress scores across both phases of the study. Significant and large reduction were evidenced in levels of rumination and depression, anxiety, and stress immediately following the ayahuasca ceremony. This effect was maintained during Phase II, with scores remaining lower than Phase I and relatively stable. Furthermore, path models did not support the mediating role of rumination in the negative link between ayahuasca ceremony effects (as indexed via ego-dissolution) and depression, anxiety, and stress scores (though evidence for mediation was found without bootstrapping samples). Findings of this study contribute to the emerging literature on the role that ceremonial ayahuasca use may have on reducing psychological distress.

The aims of the current program of research were to examine the impact of anxiety on performance and attentional control during the execution of two far aiming tasks, and to examine the efficacy of gaze training interventions in mediating these effects. Attentional control theory (ACT), which suggests that anxious individuals have impaired goal-directed attentional control, was adopted as a theoretical framework, and the Quiet Eye, characterised by long final fixations on relevant locations, was adopted as an objective measure of overt attentional control. In Studies 1 and 2 increased pressure impaired goal directed attentional control (QE) at the expense of stimulus-driven control (more fixations of shorter duration to various targets). The aim of studies 3 and 4 was therefore to examine the efficacy of an intervention designed to train effective visual attentional control (QE training) for novices, and determine whether such training protected against attentional disruptions associated with performing under pressure. In both studies the QE trained group maintained more effective visual attentional control and performed significantly better in a subsequent pressure test compared to the Control group, providing support for the efficacy of attentional training for visuo-motor skills. The aim of study 5 was to examine the effectiveness of a brief QE training intervention for elite golfers and to examine if potential benefits shown for novices in studies 3 and 4 transferred to competitive play. The QE-trained group maintained their optimal QE and performance under pressure conditions, whereas the control group experienced reductions in QE and performance. Importantly, these advantages transferred to the golf course, where QE-trained golfers reduced their putts per round by 1.9 putts, compared to pre-training, whereas the control group showed no change in their putting statistics. This series of studies has therefore implicated the role of attention in the breakdown of performance under pressure, but has also suggested that visual attentional training regimes may be a useful technique for alleviating this problem.

Depression and anxiety are common psychiatric disturbances in Parkinson's disease (PD). Past studies have demonstrated a relationship between depression and cognitive decline in PD; however, the unique influence of anxiety has not been well studied. The objective of the present study was to differentiate the unique influences of depression and anxiety on cognitive functioning in PD. Sixty-eight cognitively intact PD patients with mild to moderate motor disease severity completed self-report questionnaires and neuropsychological tests. Two hierarchical regression analyses were conducted with executive functioning performance as the criterion variable, and two additional hierarchical regression analyses were conducted with memory performance as the criterion variable. Depression and anxiety, as measured by the Depression Anxiety and Stress Scales (DASS), served as predictors for all analyses. Each set of analyses examined the amount of added, unique variance accounted for by anxiety when depression was entered as the first predictor, and also examined the amount of added, unique variance accounted for by depression when anxiety was entered as the first predictor. It was found that depression significantly predicted delayed recall memory performance when entered as the first and second predictor. In contrast, anxiety did not significantly predict performance on any of the cognitive measures. Two DASS subscales assess for the physical symptoms of anxiety, and these subscales were not significantly correlated with any cognitive variables. However, the DASS subscales tapping into non-physical aspects of anxiety were significantly associated with several cognitive variables. Patients may have endorsed physical symptoms of anxiety due to the symptoms associated with PD, and not as a result of the genuine presence of anxiety. This could have masked a potential relationship between anxiety and cognitive functioning in PD, and suggests that specific components of anxiety may be associated with cognition in PD. Future adaptation of the DASS may be necessary to differentiate the unique influences of depression and anxiety in PD patients.

Thesis (M. Sc.)--Carleton University, 2001. / Includes bibliographical references (p. 113-138). Also available in electronic format on the Internet.

The purpose of the study was to examine the impact of a natural disaster on the mental health of a rural Maya community in the Philippines. Specifically, the study assessed how an individual’s housing conditions, the household size, and general utilities can have an impact on a person’s mental health. The study used a quantitative survey design with self-administered questionnaires. Center for Disease Control and Prevention Modified Community Assessment survey was used for this research investigation. A total of 84 participants completed the survey. Participants were asked of their perceptions regarding the habitability of their own homes, the safety of their homes, whether there was mold or water damage, the size of the household, whether the household was harboring guest and the presence of general utilities such as: running water, electricity, garbage pickup, natural gas, sewage service, and cell. Descriptive (e.g. mean and frequency,), chi-squares tests, and t-test were used to analyze the data. Findings of the study showed that there was a relationship between safety of the home, the presence of mold, water damage, and running water and whether one develops symptoms of anxiety/stress. The study also found a relationship amongst garbage pickup, sewage service and whether one develops symptoms of agitated behavior. Findings of the study suggest a need for advocacy to implement mental health programs as a relief effort to disaster victims.

Decades of research in quantitative genetics have found substantial heritability for personality traits as well as for mental disorders which formed the basis of the ongoing molecular genetic studies that aim to identify genetic variations that actually contribute to the manifestation of complex traits. With regard to psychological traits, genetic variation impacting neurotransmitter function have been of particular interest. Additionally, the role of environmental factors including gene × environment interactions has been further investigated and the impor-tance of developmental aspects has been stressed. Furthermore, endophenotypes which link complex traits with their respective biological underpinnings and thus bridge the gap between gene and behaviour have begun to be included in research efforts. In accordance with this approach, this thesis aims to further examine the influence of genetic variation impacting serotonergic and dopaminergic functioning on endophenotypes of anxiety-related behaviour. To this end, two well established paradigms – the acoustic startle reflex and the cortisol stress response – were employed. Both show considerable interindividual variation which has been found in quantitative genetic studies to be at least partly based on genetic factors. In addition, the neural circuits underlying these endophenotypes are relatively well understood and thus reveal references for the detection of associated genetic influences. The results of this thesis associate the overall startle magnitude in two independent samples of young adults with a polymorphism in the promoter region of the serotonin transporter (5-HTT) gene (5-HTTLPR): Carriers of the short (S) allele which results in a reduced gene ex-pression showed a stronger startle magnitude which is in line with numerous findings linking the S allele to increased measures of negative emotionality. In addition to 5-HTTLPR, the effects of past stressful life events on the startle response were investigated: Participants who had recently experienced at least one stressful life event exhibited stronger startle responses and reduced habituation of the startle reflex although there was no 5-HTTLPR × environment inter-action effect. A third study revealed independent and joint effects of 5-HTTLPR and a poly-morphism in the dopamine receptor 4 gene (DRD4) in the same sample of young adults with regard to the cortisol stress response with carriers of the DRD4 7R allele which has been associ-ated with higher scores in sensation seeking, showing reduced cortisol responses. In addition, a 5-HTTLPR × DRD4 interaction effect emerged: 5-HTTLPR long (L) allele carriers showed the lowest cortisol response but only when they possessed at least one copy of the DRD4 7R allele. Moreover, in a fourth study a life span approach was taken and the influence of a further important serotonergic polymorphism which impacts the functioning of tryptophan hydroxylase 2 (TPH2), the rate limiting enzyme in the biosynthesis of serotonin, on interindividual differences in the startle response was investigated in three different age samples: children, young adults and older adults. There was a sex × TPH2 genotype interaction effect in a sample of young adults on the overall startle response while there was no effect of TPH2 in children or older adults. The last study of this thesis presents findings regarding the influence of two dopaminergic polymorphisms in genes encoding the enzyme catechol-O-methyltransferase (COMT) and the dopamine transporter (DAT), respectively, which both terminate dopamine signalling and are thus important regulators of dopaminergic neurotransmission, on the startle reflex in older adults. COMT met/met homozygotes showed the strongest and val/val homozygotes displayed the smallest startle magnitude which is in line with findings linking the COMT met allele to increased scores of anxiety related traits and disorders. Regarding DAT, participants homozygous for the 10R allele, which had previously associated with attention-deficit hyperactivity disorder, showed a stronger overall startle response. In sum, this thesis comprises data on interindividual differences in an electrophysiological and a hormonal endophenotype across the life span and their association with serotonergic and dopaminergic function based on genetic variation. One major finding is the clear evidence for the influence of serotonergic polymorphisms on the startle response in young adults while in contrast in older adults genetic variation in the dopaminergic system exerted considerable influence. These differences might be due to developmental processes in the different stages of life although cohort effects and effects of different recruitment strategies can also not be ruled out. Furthermore, there were significant differences regarding the genetic influence on the acoustic startle reflex and cortisol stress response in one and the same sample which might be due to methodological differences of the two paradigms as well as differences in their underlying neuronal circuits. In conclusion, this thesis supports the acoustic startle reflex and the cortisol stress response as valuable endophenotypes and thus indicators for underlying neurobiological circuits although some methodological issues remain. It also highlights the importance of taking developmental factors and changes over the course of life into account. Finally, this thesis emphasizes the necessity to include reliably and validly assessed past experienced events in molecular genetic studies in order to understand the interplay between genetic and environmental factors in shaping (endo)-phenotypes.

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