No description available.

No description available.

No description available.

No description available.

According to the biopsychosocial model of bulimia, neurobiological mechanisms called endophenotypes cause eating disordered behavior. Impulsivity has been identified as a possible endophenotype for bulimia nervosa, and individuals with bulimia who present with multiple forms of impulsive behavior are known to have worse prognoses. Executive dysfunction in impulse control purportedly manifests as behavioral under-regulation in binge-purge episodes. Neuropsychological assessments were used to analyze the relationship between impulsivity and symptoms of bulimia. Twenty-eight inpatient adolescent and young adult women with bulimia completed the D-KEFS Color Word Task, which is a version of the Stroop that contains four trials including the classic Stroop and a switching Stroop, as well as the age appropriate versions of the BRIEF rating scale and a Type-T Survey of thrill-seeking. Performance on these measures was correlated with measures of bulimia symptoms, including the EDI-3, EDE-Q, and variables of illness severity. Delay of gratification was assessed by offering subjects a choice of compensation that was either immediate and smaller or delayed and larger. Mixed results were found. The sample did not differ from the D-KEFS normative sample on total number of errors or on speed of task completion for the switching Stroop, and the sample demonstrated faster performance than the normative sample on the classic Stroop. However, a tendency to favor speed over accuracy of performance was identified. On the BRIEF rating scales, the sample self-reported significantly higher rates of executive dysfunction compared to the normative data. Additionally, some variables of impulsivity, including greater frequency of errors on cognitive tasks and self-reported deficits of executive functioning, were significantly correlated with variables of bulimia symptom severity, including self-reported bulimia symptomatology on the EDI-3 and frequency of bingeing and purgeing. Risk-taking was also found to be correlated with symptoms of bulimia. Differences were found between subjects who chose the immediate prize versus those who chose the delayed prize, including differences in cognitive task performance and symptom severity. Differences were also found for subjects with a comorbid disorder of impulse control, including bipolar disorders and substance abuse. In conclusion, a unilateral deficit of impulse control was not found to be characteristic of this sample; however, a multi-impulsive cohort was identified as having deficits of cognitive impulse control. / School Psychology

Individuals with borderline personality disorder (BPD) and high levels of BPD traits have demonstrated greater rates of engagement in risky, self-destructive behaviors compared to healthy controls. Specifically, impulsivity has been theorized to underlie many of these risky behaviors. Although existing self-report literature suggests that individuals with BPD are more impulsive than controls, evidence from behavioral measures remains inconclusive. Likewise, there is scant research examining specific domains of impulsivity associated with risky behaviors in BPD, which is problematic given that impulsivity is a diagnostic criterion for BPD. Thus, the proposed research aims to bridge this gap in the literature by examining associations between BPD traits and domains of impulsivity (e.g, urgency, lack of premeditation, lack of perseverance, and sensation seeking), using behavioral measures. Findings suggest that urgency prospectively predicts risky behaviors one-month post assessment. However, contrary to our hypotheses, BPD traits were not significantly associated with any specific impulsivity domain. Additionally, results did not support the notion that impulsivity domains account for the association between BPD traits and future engagement in risky behaviors. Future directions for examining how emotion dysregulation and interpersonal difficulties in BPD relate to impulsivity and risky behaviors are discussed.

Social anxiety is related to various comorbidities, with the most common being elevated alcohol use (Bolton et al., 2006). The symptom profile of this unique subset of cases with social anxiety and comorbid alcohol use is more complex and experiences higher resistance to treatment (Buckner et al., 2008). Both social anxiety and alcohol use emerge during the adolescent developmental period, and yet there remains a gap in the understanding of potential developmental risk factors associated with the onset and maintenance of these co-occurring symptoms. The current study investigated trait impulsivity, cognitive flexibility, and risk-seeking during adolescence and associations with alcohol use and social anxiety in young adulthood. Participants included 167 adolescents (Mage = 14.07 years, SD = 0.54; 52.7% male) followed to young adulthood (Mage = 22.30, SD = 0.69). Growth mixture models indicated that high levels of risk-seeking during adolescence predicted social anxiety in young adulthood. Contrary to hypotheses, high (compared to moderate) risk-seeking participants had lower alcohol use. Longitudinal patterns of high attentional impulsivity during adolescence into young adulthood predicated later social anxiety, whereas non-planning and motor impulsivity did not. Linear regression analyses indicated that lower cognitive flexibility during early adolescence was associated with social anxiety and alcohol use in young adulthood. Finally, moderation models suggested that global trait impulsivity was not a significant moderator of the relation between alcohol use during adolescence and social anxiety in young adulthood. This is the first work to evaluate these developmental risk-factors in relation to comorbid social anxiety and alcohol use, and has important implications for bolstering therapeutic interventions, especially for those with elevated impulsivity. / Doctor of Philosophy / Some socially anxious young adults have more difficulties with alcohol use compared to their peers. The combination of social anxiety and elevated alcohol use can lead to challenges in various aspects of life, such as school, work, and social functioning. Previous literature in the field suggests that both social anxiety and alcohol use emerge during early adolescence (ages 13-14); however, risk-factors during this important developmental period are still being explored. This dissertation evaluated the following possible risk-factors during adolescence that may be associated with the later development of social anxiety and alcohol use: trait impulsivity, cognitive flexibility, and risk-seeking. These risk-factors were explored using a dataset collected in Virginia that followed 167 adolescents over an eight-year period. Results indicated that youth with higher risk-seeking and attentional impulsivity during adolescence (ages 13-21) had significant social anxiety symptoms once they reached young adulthood (ages 22-23). Additionally, lower cognitive flexibility during ages 13-14 was associated with higher social anxiety and alcohol use in young adulthood. This is the first work to evaluate these risk-factors in relation to social anxiety and alcohol use, and has important implications for interventions, especially for those who have increased impulsivity and risk-seeking behaviors.

In der vorliegenden Studie wurde mittels der Bildgebung des funktionellen MRT die Dynamik der neuronalen Hirnmechanismen untersucht, die es dem Menschen erlauben, durch kurzfristigen Verzicht auf Belohnungen seinen Verhaltenserfolg langfristig zu optimieren. Durch den Vergleich zweier Extremgruppen gesunder Probanden (hoch- versus niedrig- impulsive Probanden) sollte ein möglicher Zusammenhang zwischen der Impulsivität und dem funktionellen Zusammenspiel frontostriataler Regelkreise während des aktiven Prozesses der Entscheidungsfindung dargestellt werden. Die vorliegende Studie hat gezeigt, dass gesunde, nicht- klinische Individuen, die sich selbst mittels der Barratt- Impulsivitätsskala als hoch- impulsiv charakterisiert haben, ihr Verlangen nach einer direkten Belohnung erfolgreich durch Aktivierung zweier komplementärer Hirnmechanismen kontrollieren können. Als erster Mechanismus ist festzuhalten, dass selbstkontrollierte Entscheidungen zu einer Abschwächung der belohnungsabhängigen Aktivierung im Nucleus accumbens führten, welche von einer ansteigenden inversen Verbindung mit dem anteroventralen präfrontalen Kortex begleitet wurde. Der zweite Mechanismus ist, dass HI- Probanden ihren Wunsch nach einer höherwertigen, aber suboptimalen Belohnung in Abhängigkeit von der Wertigkeit der unmittelbaren Belohnung durch Downregulation im ventromedialen präfrontalen Kortex kontrollierten. Diesem Mechanismus folgte eine ansteigende inverse Kopplung mit dem ventralen Striatum. Von entscheidender Bedeutung ist dabei, dass sich diese neuronalen Mechanismen qualitativ von denen der extrem- kontrollierten Probanden unterschieden. Insgesamt lässt sich sagen, dass diese Ergebnisse darauf hindeuten, dass es persönlichkeitsspezifische neuronale Mechanismen gibt, die es hoch-impulsiven Probanden ermöglichen, ihren Wunsch nach einer unmittelbaren Belohnung zu kontrollieren.

Doctor of Philosophy / Department of Psychology / Gary L. Brase / This research tested a general mediation model which proposes that individual differences (e.g., impulsivity, delay discounting, and time orientation) mediate the relationship between time perception (one’s subjective experience of the passage of time relative to actual time) and intertemporal behavior (decision-making involving tradeoffs between costs and rewards in both the present and the future). Study I did not find evidence to support the general mediation model and found that time perception was only weakly correlated with individual differences and intertemporal behavior (average r = .06) . Study II found tentative support for the proposed mediation model: individual differences in impulsivity fully mediated the relationship between time perception and intertemporal behavior in 4 separate mediation models. Three additional mediation models met the assumptions of mediation, demonstrating indirect effects significantly different from zero, but did not fully mediate the relationship between time perception and intertemporal behavior. In general, the mediation models explored in Study II (both fully and partially mediated) suggest that self-report impulsivity mediates the relationship between time perception and intertemporal health behaviors, like hours of sleep slept per night, sociosexual orientation, and frequency of eating breakfast. The findings from Study II suggest that how time is perceived influences intertemporal behavior indirectly by influencing impulsivity. Guidelines to aid future research linking time perception to individual differences and intertemporal behavior are provided.

Individuals experience risk ubiquitously, but measuring risk taking is difficult. The balloon analogue risk task (BART) was developed in order to assess risk taking through having subjects press a key that accrues reward but also risk losing all reward with each press. In humans, greater responding in this task is associated with other maladaptive risk taking behaviors. The present research modeled this relationship in pigeons due to their previously shown propensity towards risk taking behavior. Experiment 1 used an unsignaled balloon task in which losing could only occur after 5 pecks. Results showed below optimal performance with greater pecks associated with faster acquisition of risk taking in the suboptimal choice task and evidence of modulation by delay discounting measures. Experiment 2 signaled the number of pecks with colors and tested multiple hoppers as a reinforcement modality to increase performance. Results showed only signaling the number of pecks improved performance and was related to performance in the high risk BART task. Both the low and high risk variants were associated with slower suboptimal choice acquisition and again had evidence of modulation by delay discounting measures. Potential shared underlying mechanisms are discussed.