Browsing by Subject "Impulsive Behavior"
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Item Examining the Relationship Between Impulsive Personalities and Neural Functioning in Cocaine-Addicted Participants(2013-05-17) Jester, Bryan Elliott; Adinoff, Bryon H.; North, Carol S.; Spence, JeffreyBACKGROUND: Those who suffer from addiction are unable to discontinue use despite serious consequences affecting their social, professional, and family lives. Individuals who suffer from the disorder often alienate themselves from loved ones and lose their jobs. Addiction involves continuing a behavior despite severe negative consequences. Numerous studies have identified a relationship between impulsivity and the development of substance abuse. This study examines the relationship of impulsive personality facets and neural functioning associated with inhibition. SUBJECTS: The study sample included 24 healthy control participants and 56 cocaine-addicted participants. Participants ranged in age from 25 to 54 years old with a mean age of 43.27 (±SD 7.84). The group was comprised of 68 male and 12 female participants, 28.7% self identified as Caucasian, 66.3% African American, 3.8% Hispanic, and 1.3% Asian/Other. Healthy controls and cocaine-addicted participants were similar in age and race but differed in gender (p= .02). The control group had 17 males and 7 females while the cocaine-addicted group had 51 males and 5 females. METHODS: Demographic information was gathered for all participants. Each participant also completed a Neuroticism Extroversion and Openness (NEO) personality measure and Temperament and Character Inventory (TCI), Structured Clinical Interview for DSM-IV (SCID), Wechsler Test of Adult Reading (WTAR). They then performed the stop signal task (SST) during functional magnetic resonance imaging (fMRI) to gather data on neural activation during Stop-Success (SS) and Stop-Failure (SF). fMRI data was analyzed using FSL imaging software. All statistics were run with SPSS software. Functional ROIs were identified and analyzed in fMRI Expert Analysis Tool query (FEATqueary) to gather data on each participantÕs change in blood oxygen level dependent (BOLD) activation during Stop-Success (SS) and Stop-Failure (SF). Impulsive personality facets were then used to identify relationships between BOLD activations of the ROIs. RESULTS: Between group comparisons found significant differences in mean scores on all of the impulsive personality facets except for Exploratory Excitability and Persistence from the TCI, and Excitement Seeking from the NEO. Neuroimaging results are similar to other studies utilizing the SST finding changes in activation of the middle frontal gyrus, superior frontal gyrus, cingulate gyrus, medial frontal gyrus, insula, caudate and supramarginal gyrus during Stop-Failure; and superior parietal lobule, middle frontal gyrus, precuneus, supramarginal gyrus, inferior temporal gyrus, and middle occipital gyrus during Stop-Success. However, no differences in BOLD activation between groups were observed. Numerous relationships were identified between the personality facets and BOLD activation of the regions of interest (ROIs). To further elucidate this relationship between neural functioning and personality a principal component analysis (PCA) was conducted on all eleven personality facets. The PCA allowed for the identification of an impulse control personality component and an impulse drive personality component. A significant interaction with the impulse drive and the left posterior hippocampus was identified. DISCUSSION: This study allowed for the examination of how impulsive personality facets relate to, or interact with, neural functioning during a task designed to measure inhibition. Despite failing to find a difference in activation of the ROIs between cocaine-addicted participants and healthy controls, the study successfully identified the cocaine-addicted group to have a significantly more impulsive personality than healthy controls. It also identified numerous relationships between the personality facets and neural functioning. This gives credence to the idea that neural functioning and personalities are associated in some way. Reverse relationships were observed between the groups in the relationships between the Impulse Drive personality component and SF activation of the hippocampus; and the TCI facet of Purposefulness and SS activation of the right thalmus. These reverse relationships may signify a difference between the groups that may either predispose the cocaine-addicted participants to developing substance abuse, or it may be a neuro-functional change that has resulted due to prolonged exposure to cocaine.Item The Role of Impulsive Aggression in a Cohort of Suicide Attempters(2006-06-21) Hodges, Gayle Elizabeth; Claassen, Cynthia A.Research Objective: This study attempts to understand the role of impulsive aggression in a group of suicide attempters. The study hypothesized that a greater proportion of suicide attempters would meet criteria as impulsive aggressive than would be found among suicide ideators and unintentionally injured controls. The study further hypothesized that levels of impulsive aggression among all study participants would remain stable across time. Methods: Three groups of patients (n = 291) were recruited, with suicide attempters as the experimental group and suicide ideators and traumatic injury patients as control groups. Subjects were evaluated for the presence of impulsivity and aggression during initial treatment for suicidality or unintentional injury and again three months later. Two hundred one of the initial recruits also completed a follow-up assessment. Using a definition of impulsive aggression previously developed by Skodol (2002), study patients identified as "impulsive aggressive" needed to meet three criteria: the presence of significant impulsivity a measured by the Barratt Impulsivity Scale (Barratt, 1994), and significant aggression, measured using two subscales (irritability and assaultiveness) from the Buss-Durkee Hostility Inventory (Buss&Durkee, 1956). Chi-square analyses, one-way ANOVAs, and interclass correlation coefficients were utilized to compare groups, with post hoc tests used as warranted. Covariates that are known to impact impulsivity and aggression (i.e., age, race, gender, depression, borderline personality disorder, and alcohol use/abuse) were controlled. Results: Before controlling for clinical differences between groups (e.g., levels of depression, alcohol use/abuse), chi-square analysis revealed significant differences in the number of impulsive aggressive individuals by group. A post hoc analysis suggested that the percentage of impulsive aggressive individuals was significantly higher among suicide ideators than among traumatic injury patients However, when covarying for age, gender, race, borderline personality disorder, major depressive disorder, and alcohol abuse, no differences were found in the level of impulsivity, irritability, or assaultiveness between groups. There was good consistency in the proportions of individuals by group who maintained their baseline level of impulsivity, irritability, and assaultiveness at follow-up, suggesting that these characteristics function in many individuals as a trait, rather than a state. In an attempt to corroborate the validity of this study's operationalized definition of impulsive aggression, external items that assessed these tendencies were identified and analyses were performed to see if participants who endorsed impulsive aggressive behavior also endorsed these external variables. There was not a good match between groups of individuals who were classified as impulsive aggressive using the traditional BIS-11/BDHI criteria and selected external variables. Conclusions: Findings from this research study do not support an association between impulsive aggression and suicidal behaviors.