Thesis (M.D.)--University of Pennsylvania, 1802. / Microform version available in the Readex Early American Imprints series.

Thesis (M.S.)--University of Michigan, 1989.

Thesis (M.S.)--University of Michigan, 1989.

No description available.

The purpose of this investigation was twofold. First, to test the hypothesis that irritability and executive functioning (EF), two previously established risk factors for alcohol-related aggression, would interact to conjointly confer multiplicative risk for intoxicated violence that is not observed when testing either variable alone. Second, to test the hypothesis that irritability would mediate the relation between EF and alcohol-related aggression. EF was measured using seven well-established neuropsychological tests. Irritability was measured using the Caprara Irritability Scale-CIS. Participants were 310 male and female social drinkers between the ages of 21 – 35 years old. After consuming an alcohol or placebo beverage, participants were tested on a laboratory aggression task in which electric shock are given to and received from a fictitious opponent under the guise of a competitive reaction time task. Aggression was operationalized as shock intensities administered to the fictitious opponent. Results indicated that irritability successfully mediated the relation between EF and intoxicated aggression for men only. No support was found to suggest that EF and irritability together confer multiplicative risk for intoxicated aggression. Results are discussed within a cognitive neoassociationistic framework for aggressive behavior.

No description available.

Mental disorders present difficulties in the research of their mechanisms, considering the high levels of comorbidity and the lack of specific neuroscience data to evaluate them. Estipulating deficit circuits in the disorders and the best treatment is a complex task, given the limited comprehension of the factors that correlate to the disorders. The utilization of biomarkers has proved an efficient and reliable alternative to provide precise diagnosis. Among the biomarkers, the Error-Related Negativity component, an event-related cortical potential, has presented high indexes of stability and validity in correlating to anxiety, obsessive, and mood-related mental disorders. The present dissertation evaluated irritability traits in a community sample, using a Flanker task, that has consistently elicited Error-Related Negativity according to the literature. Our results corroborate literature and found a frontocentral negativity, that peaked around 100ms after the commission of an error in the Flanker Task. However, our manipulation of negative feedback did not support literature, and ERN amplitudes were less enhanced post negative feedback. The relationship between irritability and ERN remains unclear. Future studies should, therefore, address these questionings.

Background: Approximately 7% of clinically referred youth exhibit profound impairment in the ability to regulate their affect, behavior, and cognition. This phenotype – often referred to as dysregulation – has been associated with a multitude of negative outcomes. Symptom overlap between dysregulation and other psychological disorders has generated debate regarding whether DP constitutes a distinct syndrome characterized by intense, persistent irritability or is merely the combination of symptoms from disruptive or mood disorders. In order to elucidate this question, the current study examined the transdiagnostic continuities and discontinuities in three RDoC constructs (frustrative non-reward, acute threat, and cognitive control) proposed to be mechanisms of irritability Method: Participants were 294 children ages 7-17 (M=10.94; 67% male). Emotional and behavioral symptoms were measured using the Child Behavior Checklist and the Kiddie Schedule for Affective Disorders and Schizophrenia. Frustrative non-reward was measured using a frustration-induction Go/No-Go paradigm during which heart rate variability was indexed by respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP). Acute threat was measured using an Emotional Faces computer paradigm in conjunction with an eyetracker/pupilometer. Cognitive control was assessed with the Behavioral Rating Inventory of Executive Function (BRIEF), Delis-Kaplan Executive Function System (D-KEFS) and Stop Signal Task (SST). Results: Symptoms of dysregulation and non-episodic irritability were strongly, positively related. Due to a lack of demonstrated construct validity for the hypothesized RDoC constructs of frustrative non-reward, acute threat, and cognitive control, two alternative mechanisms—SNS response and cognitive dyscontrol of emotion—were derived from the data. Results showed that blunted sympathetic responsivity and poor executive control in response to emotion were predictive of more severe irritability symptoms. Finally, moderation analyses showed that among highly dysregulated children, low levels of sympathetic responsiveness were associated with more severe irritability symptoms. Conclusions: Despite phenotypic overlap with other forms of developmental psychopathology, dysregulated children can be distinguished based on the severity of their irritability symptoms. This supports the conceptualization of dysregulation as a unique syndrome characterized by intense and persistent irritability and lends credence to the novel diagnosis of DMDD. Furthermore, cognitive, behavioral and physiological patterns identified in this study suggest that difficulties with processing negative emotion—as opposed to frustration or threat specifically—may constitute a vulnerability for irritability.

Mental disorders present difficulties in the research of their mechanisms, considering the high levels of comorbidity and the lack of specific neuroscience data to evaluate them. Estipulating deficit circuits in the disorders and the best treatment is a complex task, given the limited comprehension of the factors that correlate to the disorders. The utilization of biomarkers has proved an efficient and reliable alternative to provide precise diagnosis. Among the biomarkers, the Error-Related Negativity component, an event-related cortical potential, has presented high indexes of stability and validity in correlating to anxiety, obsessive, and mood-related mental disorders. The present dissertation evaluated irritability traits in a community sample, using a Flanker task, that has consistently elicited Error-Related Negativity according to the literature. Our results corroborate literature and found a frontocentral negativity, that peaked around 100ms after the commission of an error in the Flanker Task. However, our manipulation of negative feedback did not support literature, and ERN amplitudes were less enhanced post negative feedback. The relationship between irritability and ERN remains unclear. Future studies should, therefore, address these questionings.

Mental disorders present difficulties in the research of their mechanisms, considering the high levels of comorbidity and the lack of specific neuroscience data to evaluate them. Estipulating deficit circuits in the disorders and the best treatment is a complex task, given the limited comprehension of the factors that correlate to the disorders. The utilization of biomarkers has proved an efficient and reliable alternative to provide precise diagnosis. Among the biomarkers, the Error-Related Negativity component, an event-related cortical potential, has presented high indexes of stability and validity in correlating to anxiety, obsessive, and mood-related mental disorders. The present dissertation evaluated irritability traits in a community sample, using a Flanker task, that has consistently elicited Error-Related Negativity according to the literature. Our results corroborate literature and found a frontocentral negativity, that peaked around 100ms after the commission of an error in the Flanker Task. However, our manipulation of negative feedback did not support literature, and ERN amplitudes were less enhanced post negative feedback. The relationship between irritability and ERN remains unclear. Future studies should, therefore, address these questionings.