Title from PDF of title page (University of Missouri--Columbia, viewed on Apr. 12, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. John Kerns. Includes bibliographical references.

Thesis (Ph. D.)--University of North Carolina at Greensboro, 2005. / Title from PDF title page screen. Includes bibliographical references (p. 41-49).

Flat affect (i.e., diminished expressivity) and self-reported anhedonia (i.e., lack of pleasure) are associated with many psychiatric disorders. There is a need to examine the relationship between specific anhedonia subtypes and flat affect in a non-clinical sample. Forty-seven undergraduate students (59% male; mean age 20.37; SD = 4.74) completed self-report questionnaires assessing four subtypes of anhedonia - consummatory/anticipatory by social/non-social. Participants then viewed 15 randomly-presented pictures (five neutral, ten negative) from the International Affective Pictures System while facial muscle activity (electromyography; EMG) was recorded. Male participants reporting a greater level of anhedonia, particularly consummatory social anhedonia, showed greater EMG activity change in the corrugator supercilii muscle to negative pictures, as compared with neutral pictures. Females showed the opposite pattern: more consummatory social anhedonia related to less EMG activity change in the corrugator muscle. In summary, consummatory social anhedonia in particular showed a strong relationship with facial expressivity that interacted with sex. In the presence of more consummatory social anhedonia, males show more negative facial reactions to negative stimuli while females show a more flattened affect. These findings may help explain discrepancies in existing research examining anhedonia and flat affect in clinical populations and have implications for etiology and treatments.

Boredom is a common human experience that has received little attention in the literature. To date, researchers have been unable to agree on a unified theory and definition of the construct. The present study investigated the nature of boredom by exploring its relationship to three phenomenologically similar affective states, namely apathy, anhedonia and depression. Structural equation modeling revealed that although related to apathy, anhedonia and depression to varying degrees, boredom is an empirically distinct construct. Establishing boredom as an independent construct provides an important first step in bringing the field closer to a universally accepted definition of boredom, which will undoubtedly facilitate more effective assessment and treatment of the experience of boredom, particularly in individuals with psychopathological and neuropathological illnesses in which boredom is a pervasive symptom.

Boredom is a common human experience that has received little attention in the literature. To date, researchers have been unable to agree on a unified theory and definition of the construct. The present study investigated the nature of boredom by exploring its relationship to three phenomenologically similar affective states, namely apathy, anhedonia and depression. Structural equation modeling revealed that although related to apathy, anhedonia and depression to varying degrees, boredom is an empirically distinct construct. Establishing boredom as an independent construct provides an important first step in bringing the field closer to a universally accepted definition of boredom, which will undoubtedly facilitate more effective assessment and treatment of the experience of boredom, particularly in individuals with psychopathological and neuropathological illnesses in which boredom is a pervasive symptom.

Depression is a highly debilitating illness for which there is currently sub-optimal treatment outcomes. Anhedonia (a loss of interest and pleasure) is a core symptom of depression that predicts poorer illness course and is currently not well repaired in psychological treatments. Acute and relapse prevention outcomes may be improved by clarifying which psychological mechanisms cause and maintain anhedonia, so that mechanisms can be systematically targeted in therapy. Mind wandering (a shift in contents of thoughts away from an ongoing task and/or events in the external environment to self-generated thoughts and feelings) has previously been linked to lower levels of happiness in the general population (e.g., Killingsworth & Gilbert, 2010). However, it has yet to be established if mind wandering relates to reduced positive affect in the context of depression. Therefore, the purpose of this thesis was to further explore the role of mind wandering in driving anhedonic symptoms. This thesis employed different research designs in order to establish if mind wandering is a causal mechanism driving anhedonia. Studies used a triangulation of measures to first establish correlational support (e.g. using self-report questionnaire measures, laboratory and real life positive mood inductions). Following this, studies aimed to examine if a causal relationship between mind wandering and positive affect exists by manipulating levels of mind wandering in the laboratory, real-world settings and using an empirically tested clinical intervention (Mindfulness Based Cognitive Therapy; MBCT). Using self-report measures of mindfulness and anhedonic symptoms, studies 1a and 1b found that the acting with awareness facet of mindfulness (a measure of trait mind wandering) was uniquely related to anhedonic depression symptoms in both a large community (n=440) and treatment-seeking previously depressed sample (n=409). These unique relationships remained significant when controlling for other facets of mindfulness and general depression symptoms. Study 2 (n=70) examined the relationship between mind wandering and reduced positive affect in both controlled laboratory and real world environments. Levels of mind wandering were found to be unrelated to emotional reactivity to positive laboratory mood induction tasks, but greater levels of mind wandering were significantly correlated with reduced happiness and increased sadness change to real world positive events. Next, two experimental studies were conducted on unselected samples which attempted to manipulate levels of mind wandering to observe the effect on emotional reactivity. In study 3 (n=90), a brief mindfulness manipulation of mind wandering proved unsuccessful, so it was not possible to determine how altering mind wandering impacted on positive reactivity. Analysis during the pre-manipulation mood induction revealed a significant correlation between greater spontaneous levels of mind wandering and lower self-reported happiness reactivity. In study 4 (n=95), participants followed audio prompts delivered via a smartphone application to manipulate mind wandering whilst completing everyday positive activities. This manipulation was successful but results revealed no significant condition differences in positive or negative emotional reactivity. Analysis during the pre-manipulation positive activity revealed greater mind wandering was trend correlated with reduced change in positive affect. A final empirical study (study 5; n=102) was designed to investigate the mediating role of mind wandering on the effect of MBCT on change in positive emotional experience. Recovered depressed participants undertaking MBCT were compared to recovered depressed participants in a no-intervention control group. Correlational analysis pre-intervention revealed no support for an association between mind wandering and positive reactivity to the mood induction tasks but mind wandering measured during everyday life (using experience sampling methodology; ESM) did relate to lower positive affect and higher negative affect. Participants in the MBCT group demonstrated a reduction in trait and ESM mind wandering, relative to participants in the control group. Furthermore, participants in the MBCT group demonstrated a significant decrease in anhedonic symptoms and increase in daily levels of positive affect. Change in trait mind wandering was found to mediate changes in self-reported anhedonic symptoms when controlling for change in other mindfulness facets, however change in ESM mind wandering did not mediate change in daily positive affect. MBCT also had no impact on emotional reactivity to positive mood induction tasks. Overall the findings from this thesis provide correlational support for the link between mind wandering and reduced positive affect in different testing environments. However, evidence of a causal relationship is currently limited. Consequently, a key recommendation from this thesis is to redirect attention to other driving mechanisms as targeting mind wandering in the treatment of anhedonic clients is unlikely to lead to large improvements. The theoretical, methodological and clinical implications of these findings are discussed along with suggestions for future research.

Background: There is increasing theoretical interest in the idea that a greater tendency for the mind to wander may reduce positive emotion experience, with specific interest in clinical conditions such as depression that are characterised by reduced pleasure experience (anhedonia). However, it is unclear to what degree these claims are empirically supported. Objective: A systematic review was conducted to examine the evidence regarding the association between mind wandering and positive emotion experience. Method: The Cochrane library, MEDLINE, PsycINFO, and Web of Knowledge databases were searched. A narrative discussion considered both the pattern of findings and the methodological approaches utilised in this literature. Results: 879 studies were identified and 21 relevant papers were fully reviewed, consisting of cross-sectional, prospective and manipulation studies. Conclusions: Fourteen out of 15 cross-sectional studies supported the claim that increased mind wandering was related to decreased pleasure experience. One prospective study indicated that mind wandering generally preceded but was not subsequent to reductions in positive mood. There were six studies that manipulated mind wandering experimentally, four of which found that inducing greater mind wandering led to reduced positive affect and two of which found null results. Overall, this literature supports the claim that greater mind wandering is related to reduced positive affect. However, very few studies examined this relationship in the context of depression and therefore it remains to be established if these findings generalise to clinical populations. Empiricial Paper: Previous research has established that greater levels of mind wandering are associated with reduced positive affect (PA) in the general population. The present study aims to examine whether this mechanism may mediate the relationship between depression and reduced PA (anhedonia). A community sample (N = 69) with differing levels of depression severity took part. Using experience sampling methodology, we measured mind wandering and PA during everyday life and when completing a few scheduled positive activities. To examine if mind wandering specifically influenced PA or emotion experience more generally, we additionally measured levels of negative affect (NA). Across both contexts, both greater mind wandering and greater depression severity were independently associated with reduced PA and increased NA. Greater depression severity was associated with increasing levels of mind wandering in everyday life, but not during scheduled positive activities. Mind wandering did not mediate the link between depression and reduced PA/increased NA. Exploratory analyses did however reveal that a greater tendency for the mind wander to negative rather than positive themes did mediate the link between depression and reduced PA in everyday life. We replicated previous findings that increased mind wandering is related to reduced PA and increased NA but there was no evidence that this mediated the relationship between depression and altered affective experience. However, the greater tendency for the mind to wander to negative themes may mediate the link between depression and affect. If depression treatment approaches are to target mind wandering this suggests they should therefore focus on mind wandering valence in addition to extent.

Memoria para optar al Título Profesional de Médico Veterinario / La anhedonia se describe como la disminución de la capacidad para sentir placer frente a diversas actividades, y se ha observado en humanos con ciertas patologías mentales. En otros mamíferos, como ratas y cerdos la anhedonia generada por estrés puede modificar el consumo de fuentes palatables como la sacarosa, cambiando sus preferencias. En el siguiente trabajo se estudió el efecto del estrés sobre la preferencia por sacarosa en perros. Se utilizaron 16 perros de 3–11 años, alojados en caniles, realizando pruebas de preferencia entre soluciones de sacarosa (10 g/L y 30 g/L) y agua durante 20 minutos, comparando las medias de consumo tras someter a la mitad de los animales a tres protocolos de bienestar: alimentación, paseo y enriquecimiento ambiental. Las pruebas previas a los protocolos experimentales arrojaron diferencias significativas en la preferencia según grupo etario, encontrándose mayor consumo de sacarosa 30 g/L y 40 g/L, con respecto a agua en perros adultos (≤6 años) (203,69 vs. 30,188 g. P=0,004 y 358,93 vs. 56,714 g. P=0,002), pero no en viejos (>6 años) (102,25 vs. 88,75 g. P=0,745 y 81,125 vs. 122,81 g. P=0,5), lo que podría deberse a la disminución en la percepción de los aromas en animales viejos. Sin embargo, no se observó efecto del estrés sobre las preferencias por sacarosa en ningún protocolo experimental, lo cual se condice con la alta variabilidad de resultados entre laboratorios. No obstante, esta conducta podría haberse observado con una menor variabilidad de factores intrínsecos y extrínsecos de los animales durante los ensayos, por lo que se recomiendan nuevos estudios complementarios para investigar la anhedonia en perros domésticos. / Fondo de Investigación en Ciencias Veterinarias 2014-2015

Previous research presents a paradox in relation to the value of exerting personal control such that personal control is generally reinforcing, but its value may also be limited in some individuals and under certain circumstances. Across two studies, this dissertation takes a step towards exploring the limitations of perceived control at the process-level by manipulating perceived control via the provision of choice. Manuscript 1 examined limitations of perceived control in the context of effort costs and found that actual control, but not illusory control, may be necessary to enhance motivation in the context of physical effort, suggesting that perceived control may be limited in the context of effort. Manuscript 2 examined limitations of perceived control in relation to self-reported symptoms of anhedonia and found that responsivity to personal control was diminished in those with higher levels of anhedonia. Together these studies examined factors associated with limitations in appetitive personal control and suggest avenues for future research exploring perceived control processes and how they may interface with reward processes, which has potential implications for developing interventions to alleviate reward-related deficits found in anhedonia. / Doctor of Philosophy / Past research has shown that exerting personal control (actively influencing things in your life) is generally desired and motivating, but for some individuals and in some circumstances personal control may be less desirable or motivating (sometime people do not want to be in control). Across two studies, this dissertation explored why perceived control (the belief that one has influence over outcomes in one's life) might not be desired or motivating. In both studies, participants experienced perceived control during experiments when they were given choices within computerized games, believing themselves to have control over outcomes in the game. Manuscript 1 examined how perceived control may be less desirable when people must exert physical effort and found that people may be less inclined to believe they have control when their choice leads to a physical effort requirement. Manuscript 2 examined whether people want to be in control when they are experiencing anhedonia, a set of psychiatric symptoms that includes diminished motivation and reduced responses to reward (for example, paying less attention to rewards in the environment). This study found that people with anhedonia symptoms did not seem to want to be in control as much as psychologically healthy people. During the computerized game, people with anhedonia did not try to make their own choices when they had an opportunity to. Together these studies examined different factors associated with people not wanting to be in control or finding personal control less motivating. This research has implications for developing therapies for people with anhedonia, particularly symptoms related to not actively taking control.

Although cigarette smoke has been implicated in a causal relationship with various types of cancers, around 62% of all cancer patients are current smokers, recent quitters, or former smokers. While most patients who are smokers are motivated to quit after cancer diagnosis, 25 -30% of these patients continue to smoke. Furthermore, most quitters relapse after 2-3 years of post-chemotherapy. This represents a major health concern since several clinical studies revealed that perpetuation of smoking in cancer populations attenuates patient's well-being and quality of life. Smoking may impair healing, attenuate the efficacy of chemotherapy, increase the disease complications and diminish survival rates. However, the factors that involved in nicotine dependence in cancer patients are poorly understood. xii According to human research, it was suggested that tumor site, impact of cancer therapy and disease prognosis could be responsible of continuation of tobacco smoking among cancer patients and survivors. Recently, chemotherapy was shown to cause emotional deficits in humans (anxiety, insomnia and depression) and animals. In this project, we focused on the chemotherapeutic agent, paclitaxel, because it is widely used to treat solid tumors such as lung, head, neck and breast cancer. We previously reported that paclitaxel induced general affective deficits in mice such as anhedonia, anxiety and depression-like behaviors. We therefore hypothesized that the chemotherapeutic agent, paclitaxel may alter the rewarding and withdrawal properties of nicotine. We investigated the impact of paclitaxel on spontaneous nicotine withdrawal and nicotine reward in C57BL/6J mice by using variety of behavioral tests. Our findings showed that paclitaxel worsened the somatic and affective signs of nicotine withdrawal in male mice as well as attenuated of nicotine reward in the CPP assay. These behavioral changes were not due to an impact of nicotine metabolism by paclitaxel. Overall, paclitaxel changed the behaviors during nicotine withdrawal and reward and that suggested changing in the smoking behavior after exposure to chemotherapy.