Maj Mark Bates,
USAF
Department of Medical and Clinical Psychology
Doctor of
Philosophy
2002
Major Advisor: Wendy Law, Ph.D., Department of Medical and Clinical Psychology
Dissertation Title: Risk Factor Model Predicting the Relationship between Stress and Performance in Explosive Ordnance Disposal Training
ABSTRACT
Stress is a common aspect of military operations. It therefore follows that
training to work effectively under conditions of stress is an essential component
of military training programs. The primary purpose of this proposed study
is to identify specific risk and protective factors that predict the effects
of stress responding on military operational performance. Because of the high
levels of stress and resultant program attrition, the military's Explosive
Ordnance Disposal (EOD) training program provides a unique opportunity to
study the interaction between stress and performance, and to identify specific
risk and protective factors.
The study recruited 500 students who were enrolled in EOD training. These
students were enlisted personnel in the US military who volunteered to participate
in the study at two points during the training program. Self-report assessments
of potential risk factors were collected at the beginning of the training
program and at one intermediate time point that is associated with the highest
level of student attrition. These risk factors included general cognitive
ability, inattention and impulsivity, problem solving, anxiety, personality
dimensions, social relations, and stressful events. In addition, the study
explored the role of the demographic, social desirability, and external stressor
control variables. The risk factors and control variables were used to predict
two measures of performance. The first measure of performance was the grade
on the first practical test of the training program, a continuous outcome
between 0-100. The second performance measure was program completion, which
was a dichotomous outcome of successful or unsuccessful completion.
The
statistical procedures included multivariate analyses to identify unique predictors
of performance and interactional analyses to clarify how pairs of variables
might be interacting to affect performance. A substantial number of variables
were found to predict performance on a univariate level. However, only select
demographic variables, trait inattention, and situationally experienced cognitive
anxiety emerged as key predictors of performance in multivariate comparisons
of predictors. The findings also suggested that trait problem-solving skills
might act as a protective factor against the negative performance effects
associated with trait inattention. Finally, even though trait inattention
was found to be a risk factor for poorer performance, the findings also suggested
that inattention could be associated with enhanced performance if paired with
either situational variables of high utilization of problem solving skill
or low cognitive anxiety experienced during a test.
Bonnie Roberts
Chavez
Department of Medical and Clinical Psychology
Doctor of
Philosophy
2003
Major Advisor: Neil E. Grunberg, Ph.D., Professor, Department of Medical and Clinical Psychology
Dissertation Title: Effects of Stress and Relaxation on Time Perception
ABSTRACT
Changes in time perception during and following experiences of stress and relaxation are commonly reported, but little is known about the direction and nature of any time perception changes. In this experimental study, men and women ages 18 to 79 were randomly assigned to one of three conditions: stress (n = 39) - speech preparation and presentation, relaxation (n = 38) - a progressive muscle relaxation exercise, or control (n = 39) - listening to a biography on tape. Multiple measures of time production, time estimation, perceived rate, and attention to time domains (past, present, and future) were made before and after the experimental phase. Retrospective time estimates were made after the experimental phase. Self report, physiological, and biochemical measures of stress were used to evaluate response to the experimental conditions, and results were consistent with increased stress in the stress condition and increased relaxation in the relaxation condition. Measures of duration judgment were relatively consistent within individuals with larger variance from person to person. Some of the individual variance was associated with gender and age with women having generally larger duration judgment ratios (subjective/objective time) than did men (t(110)=2.91, p<.01) and age was significantly correlated with duration judgment ratio. Time was reported to pass slower than usual during relaxation (t(34) = 5.37, p<.01), but time spent relaxed was remembered as significantly shorter than time spent in the control activity (F(2,108) = 9.88, p <.01). Stress led to increases in subjective to objective time ratio (t(37) = 2.34, p <.05), and time following a period of stress was reported to pass quickly. Attention to the present was related to lower reported distress, whereas attention to the past was positively correlated with self-reported distress. These data imply that changes in time perception may reflect changes in experiences of stress or relaxation. Also, interventions to increase focus of attention on the present may be helpful to reduce distress.
Martha
M. Faraday
Department of Medical and Clinical Psychology
Doctor of
Philosophy
2000
Major Advisor: Neil E. Grunberg, Ph.D., Department of Medical and Clinical Psychology
Dissertation Title:
The Role of Sex and Strain in Behavioral and Biologic
Stress Responses of Rats
Abstract
Stress has been implicated in the etiology of many behavioral disorders (i.e., drug abuse, feeding disorders) and disease states (i.e., hypertension, diabetes, depression). Individuals differ, however, in vulnerability to stress- related disease. The goal of this doctoral research was to identify potential behavioral and possibly biochemical markers of stress vulnerability vs. resilience in male and female rats of two strains (Sprague-Dawley and Long-Evans) that might predict eventual development of specific stress-related behavioral disorders or diseases in certain subgroups of humans. The experiment assessed the effects of mild, repeated daily stress on multiple behaviors and biochemical indices within the same subjects to construct a detailed model of potential markers of stress vulnerability vs. resilience.
Specifically, subjects were exposed to no stress or to 20 min/day immobilization stress for three weeks. During this period, behaviors were measured in two domains: 1) body weight, feeding, and locomotion; and 2) acoustic startle reflex and pre-pulse inhibition, passive avoidance, and Morris water maze performance (three measures of cognitive performance). Hormones of the hypothalamo-pituitary-adrenocortical (HPA) axis were measured at the end of the experiment.
The major findings were: 1) the four subgroups (i.e., two strains of male and female rats) manifested behavioral stress responses that varied with the domain assessed (i.e., feeding, body weight, and activity vs. cognitive performance) and imply different stress vulnerabilities; 2) the four subgroups manifested consistent stress responses within each behavioral domain, suggesting that stress vulnerability may be domain-specific; and 3) stressed animals within each of the four subgroups manifested changes in HPA axis hormones consistent with a stress response. Therefore, behaviors, rather than HPA axis hormones, most clearly differentiated apparent subgroup vulnerabilities. In addition, the findings suggest that certain behaviors (i.e., feeding, acoustic startle and pre-pulse inhibition) may have utility as behavioral markers for domain-specific types of stress vulnerability in humans.
Grant D. Huang
Department of Medical and Clinical Psychology
Doctor of
Philosophy
2001
Major Advisor: Michael Feuerstein, Ph.D., Department of Medical and Clinical Psychology
Dissertation Title: Workplace Stressors and Musculoskeletal Symptoms: Examining the Combined Impact of Ergonomic and Work Organization Factors
ABSTRACT
Work-related musculoskeletal symptoms are a significant public health challenge that have been associated with ergonomic and occupational psychosocial (i.e., work organization) factors. However, research still needs to delineate the specific dimensions of work organization that pose risks to workers. It is also unclear whether workplace physical and psychosocial stressors have a combined effect for these symptoms. Individuals (n = 289) from a population (U.S. Marines Corps) known to have a high rate of clinic visits associated with low back and upper extremity disorders were given a questionnaire containing items on demographics, health behaviors, level of physical exertion at work, family and life stressors, ergonomic factors, and work organization. After identifying specific work organization variables related to scheduling, job design, management style, career concerns, organizational characteristics, and interpersonal factors, logistic regression analyses were conducted to determine risks for low back symptoms only, upper extremity (UE) symptoms only, or concurrent low back and upper extremity symptoms. The occurrence of low back symptoms was associated with: age (OR = 1.09); family conflict (OR = 1.30); exposure to ergonomic stressors (OR = 1.03); time pressure at work (OR = 1.18); and, interpersonal demands at work (OR = 0.73). Risks for UE symptoms were: family conflict (OR = 1.27); exposure to ergonomic stressors (OR = 1.02); and, time pressure at work (OR = 1.16). Risk factors for the occurrence of both low back and UE symptoms were: age (OR = 1.13); exposure to ergonomic exposures (OR = 1.04); greater levels of interpersonal demands at work (OR = 1.56), work-related cognitive demands (OR = 1.20), and cognitive uncertainty (OR = 1.22); and, lower levels of skill discretion (OR = 1.09). Among the different ergonomic and work organization combinations, the occurrence of either low back symptoms or upper extremity symptoms was associated with higher levels of both ergonomic stressors and time pressure (OR = 2.61 & 2.90, respectively). Higher levels of ergonomic stressors and lower levels of involvement in management decisions (OR = 2.50) as well as higher levels of ergonomic stressors and time pressure (OR = 2.21), cognitive demands (OR = 2.25), cognitive uncertainty (OR = 2.08), interpersonal demands (OR = 2.44), or positive organizational climate (i.e., greater perceived responsibility) (OR = 2.15) were all risks for cases with both low back and upper extremity symptoms. These findings indicate the importance of distinguishing specific aspects of work organization and the need to concurrently assess them in conjunction with ergonomic risk factors in future research. They also highlight the potential of workstation and job redesign, job stress management, and organization-based efforts that incorporate worker input/involvement in reducing the levels of ergonomic stressors and work demands associated with low back and upper extremity symptoms.
Capt Teresa M. Hughes
Department of Medical and Clinical Psychology
Doctor of Philosophy
2003
Major Advisor: Tracy Sbrocco, Ph.D., Department of Medical and Clinical Psychology
Dissertation Title: Understanding the Regulation of Body Weight:
A Focus on Eating Patterns, Energy Intake, and Metabolic Rate
ABSTRACT
The clinically observed eating pattern of gorging (eating fewer, larger meals later in the day) is ill defined in the literature and inconsistently linked to metabolic rate suppression and body composition. The purpose of this study was to further understand the relationship between gorging, metabolic rate, and body composition with a consideration of daily physical activity and purposeful exercise. Gorging was defined as two or fewer meals per day with at least seven hours between waking and the first meal for at least three days per week. It was hypothesized that gorgers would have 1) lower metabolic rates, 2) more body fat, 3) lower energy and higher fat intakes, and 4) more pathological eating attitudes than non-gorgers. Participants were 12 obese gorging (OG), 11 obese non-gorging (ON), 14 normal weight gorging (NG), and 14 normal weight non-gorging (NN; age-matched), non-smoking, otherwise healthy women. Metabolic testing included assessment of resting metabolic rate (RMR), active metabolic rate (AMR) while riding a stationary bicycle at a rate of 50 rpm and workload of 1kg, and dietary induced thermogenesis (DIT) where postprandial metabolic rate was assessed. Results were partially supported. Contrary to the first hypothesis, the eating pattern groups did not differ by RMR [F(1,47) = 3.96, p = 0.05], AMR [F(1, 47) = 2.03, p = 0.16], or DIT [F(1, 47) = 0.40, p = 0.53] after covarying lean body mass. Lean body mass was the best predictor of metabolic rate accounting for 72% of the variance. These findings are limited by the small effect sizes for these analyses. Future investigations should increase statistical power and consider increasing the both the exercise and meal challenges so they may have a greater affect on metabolic rate. The eating pattern groups did not differ by body composition [F(1,47) = 1.02, p = 0.32], contrary to the second hypothesis. However, the gorging group reported less energy intake than the non-gorging group [F(1,47) = 14.50, p = 0.001] supporting the third hypothesis. Estimated energy intake for the participants was calculated using measured RMR multiplied by an activity factor of 1.3. Based on these results the gorgers underreported food intake to a greater degree than the non-gorgers. There was an interaction effect for fat consumption. The ON consumed the greatest amount of fat followed by the obese and normal weight gorgers, and then the NN group. Contrary to the fourth hypothesis, there were no significant differences between the eating pattern groups’ eating pathology. This was one of the first studies to thoroughly operationalize gorging and examine existing eating patterns. While several of the major hypotheses were not supported, the results of this study do support the importance of the relationship between weight regulating behaviors, body composition, and metabolic rate. The findings are clearly worth further study and it is clear that a biopsychosocial framework is needed when examining the interrelationship of eating patterns and metabolism.
Kimberly L.
Kalupa
Department of Medical and Clinical Psychology
Doctor of
Philosophy
2003
Major Advisor: Tracy Sbrocco, Ph.D., Associate Professor, Department of Medical and Clinical Psychology
Dissertation Title: The impact of a low-fat diet and the use of fat substitutes on fat preferences among overweight women seeking weight loss treatment
ABSTRACT
Overweight
and obesity form the basis of the second leading cause of preventable death
in the United States and are on the rise ENRfu(NIH, 1998). Traditionally,
recommendations for weight loss include a reduction in dietary fat (Drewnowski,
1990). However, adherence to low-fat diets remains a challenge. Hedonic responses
to food may be important to understand the adherence problem. When compared
to bland-tasting foods, nutritionally-equivalent foods that are flavorful
are more satiating (Rolls, 1995; Warwick et al., 1993). Two previous studies
that examined the sensory impact of dietary fat modification reported conflicting
results (Mattes, 1993; Guinard et al., 1999).
The current study evaluated the impact of dietary fat modification on fat
preference in three weight loss groups. The impact of changes in fat preference
on short-term adherence to a 6-week weight loss program was assessed. Sixty-one
otherwise, healthy overweight women (BMI 25-37 kg/m2) between the ages of
18-60 were randomly assigned to one of three brief, 6-week weight loss programs.
All three groups were asked to reduce dietary intake to 1800 kilocalories
per day, but one group was asked to maintain fat at 36%, and two additional
groups were asked to consume 20-25% of kilocalories in fat. One low-fat group
was instructed to use fat substitutes and the other was instructed to avoid
substitutes. It was hypothesized that decreased fat intake and sensory exposure
to fat would cause a decrease in preference for high fat foods.
Excellent adherence was observed with over 91% of participants completing treatment. In addition, guidelines regarding kilocalories, respective fat intake, fat substitute use were followed. Taste changes that occurred were subtle and did not affect on short-term dietary adherence. More time on the prescribed fat levels might be required to induce a change in fat preference. Differential changes in fat preference following dietary fat modification were expected, but not observed in the current investigation. However, results suggest that a modified 6-week Behavior Choice program might be a viable treatment option for women in this age and weight category (BMI < 37 kg/m2).
Jennifer M. Phillips
Department of Medical and Clinical Psychology
Doctor of Philosophy
2006
Major Advisor: Neil Grunberg, Ph.D., Department of Medical and Clinical Psychology
Thesis Title: “Effects of Clozapine and Alprazolam on Cognitive
Deficits and
Anxiety-like Behaviors in a Ketamine-Induced Rat Model of Schizophrenia”
ABSTRACT
Schizophrenia is a debilitating mental illness that affects
approximately 2.2 million Americans (1% of the population) each year. Despite
the large number of people affected by schizophrenia, there is no known cure
for this disorder but antispychotics help to manage the symptoms of schizophrenia.
Unfortunately, antipsychotic medications are frequently accompanied by debilitating
side effects (e.g., extrapyramidal side effects, tardive dyskinesia) and low
compliance. Alternative pharmacological treatment options are needed to improve
the treatment and quality of life for individuals suffering from schizophrenia.
This doctoral research project examined the hypothesis that the cognitive
deficits associated with schizophrenia can be medicated indirectly using anxiolytics,
drugs that decrease anxiety, based upon a proposed relationship between anxiety
and cognitive disruptions in schizophrenia. The current research also evaluated
the validity and potential usefulness of ketamine administration to create
a novel animal model that includes symptoms of schizophrenia and anxiety.
Two experiments were conducted to address these goals. Experiment #1 examined
the effects of clozapine (an antipsychotic), alprazolam (an anxiolytic), and
a combination treatment on ketamine-induced cognitive disruptions in prepulse
inhibition (PPI) of the acoustic startle reflex and passive avoidance. Experiment
#2 examined the effects of clozapine, alprazolam, and a combination treatment
on ketamine-induced anxiety-like behaviors on the elevated plus maze, open
field test, and social interaction test.
The major findings of the study were: (1) ketamine administration caused cognitive
disruptions in PPI as well as passive avoidance; (2) only clozapine attenuated
the cognitive disruptions caused by ketamine, and only in the PPI measure;
(3) ketamine administration caused an increase in anxiety-like behaviors on
the EPM, open field locomotor activity, and social interaction; (4) only alprazolam
decreased the ketamine-induced increases in anxiety-like behaviors, and only
in the measure of social interaction. The findings failed to support the hypothesis
that ketamine-induced cognitive deficits could be attenuated with anxiolytic
medications. In addition, these findings suggest that ketamine administration
may provide a useful, but limited, model of concurrent symptoms of schizophrenia
and anxiety.
Casey Skvorc
Department of Medical and Clinical Psychology
Doctor of
Philosophy
2001
Major Advisor: Neil E. Grunberg, Ph.D., Department of Medical and Clinical Psychology
Dissertation Title: Perception of Personal Well-Being and Workers' Compensation Injuries in Federal Correctional Workers
ABSTRACT
Federal correctional workers are tasked with protecting society from felons convicted of federal crimes and remanded to the custody of the Attorney General for incarceration. The physical and psychological demands placed upon these workers are great, and these workers have greater risk factors for occupational injury and disease than do other federal law enforcement officers. This dissertation examines rates of occupational injuries for approximately 30,000 federal correctional workers with regard to the security level of the prison worked in, the occupation of the correctional worker, gender, and associated number of days away from work after an occupational injury. Also analyzed is a Perception of Personal Well-Being (PWB)instrument, part of a widely circulated self-report measure of physical and emotional well-being administered to federal correctional workers on a nationwide basis. It was hypothesized that security level, and occupation, would be related to higher levels of occupational injury, lower levels of PWB, and that higher security levels would be associated with significantly lower levels of perception of personal well-being. Security level is significantly related to rates of occupational injury, in that federal correctional workers at Minimum security institutions had lower odds for the occurrence of occupational injuries than all other security levels except the AdMax security level. Security level was not a significant predictor for aggregate perception of well-being. Correctional officers had higher rates of occupational injuries than non-correctional officers. Security level was not a significant predictor of aggregate measures of PWB. Correctional officers had higher aggregate scores of PWB than non-correctional officers. Males had higher injury rates per 100 staff than females, and correctional officers had higher injury rates per 100 staff than non-correctional officers. Staff working at minimum security prisons had lower rates of injury per 100 staff than all other security levels. Male staff had higher mean levels of COP days than female staff, and correctional officers had higher numbers of COP days than non-correctional officers. The North Central region had higher a higher injury rate per 100 staff of all the regions, and the lowest mean level of COP days after an injury of all the regions. Male staff had higher levels of PWB than female staff, and correctional officers had higher levels of PWB than non-correctional officer staff.
Captain Julie
M. Storey
Department of Medical and Clinical Psychology
Doctor of
Philosophy
2001
Major Advisor: Michael Feuerstein, Ph.D., Department of Medical and Clinical Psychology
Dissertation Title: Job Stress Reactivity and Work-Related Musculoskeletal Symptoms
ABSTRACT
Research regarding risk factors and correlates of work-related upper extremity (WRUE) symptoms and disorders have identified important ergonomic, workplace psychosocial, and individual psychosocial factors in their etiology, exacerbation and maintenance. Elevated levels of job stress have been frequently reported in this population, and epidemiological studies indicate job stress is associated with symptom severity, functional limitations, and lost work time in individuals with a variety of work-related upper extremity disorders. Although plausible pathophysiologic mechanisms exist linking the stress response to WRUE symptoms, little is known about the specific effects of stress on potential musculoskeletal and sympathetic nervous system mediators and how they may impact WRUE symptoms. Additionally, it is unclear if workers with these difficulties respond differently to stressors than asymptomatic workers. The present study was an exploratory investigation designed to address four primary questions: 1) do individuals with WRUE symptoms report higher levels of job stress and ergonomic exposure than asymptomatic individuals; 2) do workers with WRUE symptoms respond with greater musculoskeletal, neuroendocrine, and psychological responses than asymptomatic workers; 3) can ergonomic, psychosocial and physiological variables significantly discriminate between symptomatic and asymptomatic workers; and, 4) if they can discriminate between the groups, are the discriminating factors associated with general and WRUE-specific clinical outcomes. Female computer-users (n = 30; 16 symptomatic and 14 asymptomatic controls matched for age, body mass index, and job type) completed self-report measures of general health status, symptoms job stress, and ergonomic exposure and kept a 2-week diary of stressful work events and symptoms. At the end of the two-week monitoring period, participants were exposed to a laboratory-based job stress recall task while bilateral forearm activity (extensor and flexor), blood pulse volume, salivary cortisol levels, and self-report measures of symptoms and distress were monitored. Analyses of the self-report and job stress diary data indicated no significant differences between the groups on the frequency or intensity of job stress. However, symptomatic workers reported significantly greater distress in response to their peak stress event. Psychophysiologic data indicated significant group main effects for heart rate and forearm flexor muscle activity, where symptomatic workers exhibited higher tonic heart rate and flexor activity across all time periods. No group main effects were observed for forearm extensor, salivary cortisol, distress or symptoms, and no significant group by period interactions were observed for any of the measures. Canonical discriminant function analyses revealed that ergonomic exposure and job/family stress and coping were relatively poor discriminators between the groups while psychophysiologic response to the job stress recall task and a multifactorial model combining significant discriminators from all three domains (i.e., percent of work time at a computer workstation, the Impact of Events Scale-Revised, nondominant flexor activity during the stressor period, and heart rate during the recovery period) were good discriminators between the groups, classifying 89% and 92.3% of the sample respectively. Stepwise multiple regression analyses indicated this multifactorial model accounted for a significant amount of the variance in WRUE-specific outcomes (i.e., self-reported UE pain, functional limitations, and UE symptom severity), but not general physical or mental health. Results suggest that important ergonomic, psychosocial and physiological differences exist between these groups, including potential tonic heart rate elevations, tonic forearm musculature hyperarousal, and a tendency to experience prolonged cognitive and behavioral consequences to stressful events. These differences not only discriminate between the two groups but also are also associated with WRUE-specific clinical outcomes. Theoretical implications as well as questions for future research are discussed.
Dana L. Tucker
Department of Medical and Clinical Psychology
Doctor of
Philosophy
2002
Major Advisor: David S. Krantz, Ph.D., Department of Medical and Clinical Psychology
Dissertation Title: Hostility and Anger Expression: Behavioral and Cardiovascular Responses to Mental Stress among Cardiovascular Disease Patients
ABSTRACT
Hostility and anger expression have been postulated as contributing factors to cardiovascular disease and have been associated with cardiovascular reactivity and stress-induced myocardial ischemia. The present research investigates relationships between hostility, anger expression, and defensiveness and cardiovascular measures of reactivity and ischemia. The study is an analysis of previously collected data from the Triggers of Myocardial Ischemia Study, in which participants underwent mental stress tasks (math, anger recall speech, and Stroop Color-Word) with concurrent assessments of cardiovascular reactivity and ischemia as well as brief emotional state assessments in the laboratory. Outside of the laboratory, a subset of these participants (n= 59) completed a set of questionnaires including the Marlowe-Crowne Scale of Social Desirability and the Cook-Medley Hostility Scale.
Results indicated that higher Cook-Medley Hostility scores were positively correlated with anger expression changes following the math task (r=.308, p< .05), and Composite Hostility predicted anger expression changes to the same task (r=.334, p<.05). The Composite Hostility component Hostile Affect was a significant predictor of anger expression changes during all three tasks. Although hostility measures did not appear to be consistently predictive factors in stress-induced cardiovascular reactivity, changes in anger expression predicted systolic and diastolic blood pressure changes during the anger recall task, and marginally predicted heart rate changes to anger recall. Higher Total Hostility was marginally related to presence of ischemia during Anger Recall and Stroop tasks, but anger expression changes were not related to presence of ischemia. Hypothesized interaction effects between hostility and anger expression in eliciting cardiovascular reactivity and ischemia were not observed. Defensiveness, contrary to predictions, was not significantly negatively associated with anger expression changes, nor was it a significant predictor of cardiovascular reactivity or ischemia.
The
study suggests the importance of assessment of acute emotional states when
assessing personality characteristics and their impact on measures of cardiovascular
reactivity and ischemia. Study limitations include low power in the evaluation
of factors related to myocardial ischemia, and the study's use of a data set
not specifically designed to test the present study hypotheses. Further investigation
into anger expression in addition to personality traits may help in understanding
factors contributing to cardiovascular reactivity and adverse coronary events.