Biomedical subjects

Michael S McCloskey

Publications and source records attributed to Michael S McCloskey.

9 recordsLinked to original sources

PubMed2007

Amygdala and orbitofrontal reactivity to social threat in individuals with impulsive aggression.

BACKGROUND: Converging evidence from animal and human lesion studies implicates the amygdala and orbitofrontal cortex (OFC) in emotional regulation and aggressive behavior. However, it remains unknown if functional deficits exist in these specific brain regions in clinical populations in which the cardinal symptom is impulsive aggression. We have previously shown that subjects diagnosed with intermittent explosive disorder (IED), a psychiatric disorder characterized by reactive aggressive behavior, perform poorly on facial emotion recognition tasks. In this study we employed a social-emotional probe of amygdala-OFC function in individuals with impulsive aggression. METHODS: Ten unmedicated subjects with IED and 10 healthy, matched comparison subjects (HC) underwent functional magnetic resonance imaging while viewing blocks of emotionally salient faces. We compared amygdala and OFC reactivity to faces between IED and HC subjects, and examined the relationship between the extent of activation in these regions and extent of prior history of aggressive behavior. RESULTS: Relative to controls, individuals with IED exhibited exaggerated amygdala reactivity and diminished OFC activation to faces expressing anger. Extent of amygdala and OFC activation to angry faces were differentially related to prior aggressive behavior across subjects. Unlike controls, aggressive subjects failed to demonstrate amygdala-OFC coupling during responses to angry faces. CONCLUSIONS: These findings provide evidence of amygdala-OFC dysfunction in response to an ecologically-valid social threat signal (processing angry faces) in individuals with a history of impulsive aggressive behavior, and further substantiate a link between a dysfunctional cortico-limbic network and aggression.

Adult↗

PubMed2005

Intermittent explosive disorder-integrated research diagnostic criteria: convergent and discriminant validity.

Research on intermittent explosive disorder (IED) has been hindered by vague and restrictive DSM-IV diagnostic criteria. Integrated research criteria have been developed for IED (IED-IR) that address the DSM-IV criteria's shortcomings. The purpose of this study was to examine the convergent and discriminant validity of the IED-IR criteria set by comparing adults meeting these criteria (n=56) to healthy controls (n=56) and to individuals with an Axis I major mental disorder (n=33) or an Axis II personality disorder (n=22) diagnoses on measures of aggression (self-report and behavioral) and global functioning. IED-IR individuals demonstrated higher levels of aggression compared to the other three groups, and were rated as more impaired than the healthy control and Axis I individuals. Subgroup analyses showed that IED-IR subjects who did not meet DSM IED criteria did not differ from DSM IED subjects on self-report measures of aggressiveness or global functioning. Furthermore, the IED-IR subjects evidenced more behavioral aggression than their DSM-IED counterparts.

Adolescent↗

PubMed2005

Neuroimaging and personality disorders.

Within the past several years, neuroimaging research on personality disorders has begun to develop. Personality disorders can be thought of as trait-like dysfunctional patterns in cognitive, affective, impulse control, and interpersonal domains. These domains of dysfunction have been linked to specific neural circuits. Developments in brain imaging techniques have allowed researchers to examine the neural integrity of these circuits in personality-disordered individuals. This article reviews the neuroimaging literature on borderline personality disorder, antisocial personality disorder (including psychopathy) and schizotypal personality disorder. Functional and structural studies provide support for dysfunction in fronto-limbic circuits in borderline and antisocial personality disorder, whereas temporal lobe and basal striatal-thalamic compromise is evident in schizotypal personality disorder.

Antisocial Personality Disorder↗

PubMed2004

High prevalence of personality disorders among healthy volunteers for research: implications for control group bias.

Individuals who volunteer as control subjects for clinical studies are regularly screened for Axis I diagnoses, but seldom screened for Axis II disorders. This study examined the relative rates of Axis II diagnoses among 341 volunteers passing an initial telephone screen for entry into biological research studies. Axis I and II diagnoses by DSM-IV were assigned by best estimate after structured clinical interview, and subjects were categorized into one of three groups based on their diagnostic profiles: (1) volunteers without lifetime Axis I or II diagnoses ("healthy controls"), (2) personality-disordered volunteers without any history of Axis I pathology, and (3) personality-disordered volunteers with past (but not current) Axis I pathology. The results revealed a high prevalence of personality disorders (44.4%) among these volunteers. Several clinically relevant self-report inventories were used to demonstrate important characterological differences between the three comparison groups. Although inventory results demonstrated multiple differences between all three groups, most scales revealed differences between healthy controls and the two personality-disordered groups (with or without lifetime Axis I diagnoses), suggesting that most of the variance was accounted for by the presence or absence of an Axis II disorder, not a past Axis I disorder. These results suggest that personality-disordered volunteers may bias a control group due to the infrequent screening for Axis II disorders among volunteers for medical and psychiatric research. Implications are discussed for routine Axis II screening of volunteers for research with specific diagnostic instruments.

Adult↗

PubMed2004

The effects of diazepam on human self-aggressive behavior.

RATIONALE: Diazepam, a benzodiazepine with a relatively rapid onset of clinical effects, has been associated with suicide and other self-aggressive acts. The evidence for this association, however, comes exclusively from retrospective non-experimental studies. Although suggestive, the results of these studies do not support a cause-and-effect relationship between benzodiazepine consumption and self-aggressive behavior. OBJECTIVE: To experimentally examine the effect of diazepam on human self-aggressive behavior under controlled laboratory conditions. METHOD: Forty-six healthy men and women were randomly assigned to receive placebo, or 5 mg or 10 mg diazepam in a double-blind, between-groups design. Participants were then provided the opportunity to self-administer electric shocks during a competitive reaction-time task (the self-aggression paradigm, SAP). Self-aggression was defined by the intensity of shock chosen. RESULTS: Diazepam (10 mg) was associated with higher average shock self-administered than placebo. Subjects receiving 10 mg diazepam were also more likely to attempt to self-administer a shock that they were led to believe was "severe" and painful. Sedation effects were found, but diazepam consumption did not impair memory, attention, concentration, pain threshold, or reaction-time performance. CONCLUSIONS: Clinically relevant diazepam doses may be associated with self-aggressive behaviors at levels that do not significantly impair basic cognitive processes or psychomotor performance.

Adult↗

PubMed2004

A brief group cognitive-behavioral intervention for social phobia in childhood.

Twenty-three preadolescent children (ages 8-11) meeting criteria for social phobia were randomly assigned to either a 3-week cognitive-behavioral group intervention or a wait-list control group. The intervention consisted of psychoeducation, cognitive strategies, and behavioral exposure. Outcome measures included diagnostic interview as well as parent and child report measures of anxiety and depression. Improvements were observed at posttest, with results stronger for parent report and interviewer ratings than for child self-report. At 3-week follow-up, children receiving the intervention demonstrated significant improvements on the majority of child, parent, and interviewer reports of social anxiety and related symptoms relative to wait-list participants. Preliminary support is provided for the utility of a brief intervention for preadolescent children with social phobia. Limitations and implications for future research are discussed.

Adolescent↗

PubMed2004

Suppression of attentional bias in PTSD.

Sixty combat veterans with posttraumatic stress disorder performed an emotional Stroop task under 1 of 4 contextual conditions designed to test theoretical explanations for an attentional bias suppression effect. Results revealed that when the emotional Stroop task was performed under conditions involving a future threat of either watching a combat video or giving a speech, attentional bias was inhibited. There was limited support for the prediction that the suppression effect was strongest when stressor content matched word content on the Stroop. In contrast to participants in the threat conditions, veterans who believed that they would receive additional compensation for speeded color naming or who believed that they would have no other experimental demands were slower when color naming combat-threat words. Potential theoretical explanations of the findings are discussed.

Attention↗

PubMed2003

Alcohol intoxication and self-aggressive behavior.

Nonexperimental field studies have demonstrated an association between alcohol intoxication and self-aggressive behaviors across the spectrum of lethality. Although these results are suggestive, it is not yet known whether alcohol intoxication is causally related to self-aggression. The authors therefore experimentally examined the effects of alcohol intoxication (mean blood alcohol concentration of .10) on a behavioral measure of self-aggression in men (N = 40). After consuming either an alcohol or a placebo drink, participants were provided the opportunity to self-administer shock during a task disguised as a reaction-time game, with self-aggression defined by the intensity of shock chosen. Half of the participants observed a self-aggressive model (a potential moderator of alcohol-related self-aggression). Independent alcohol and model effects were found, with alcohol accounting for over 30% of the self-aggression variance.

Adult↗

PubMed2003

Diverse research on alcohol and aggression in humans: in memory of John A. Carpenter.

This article summarizes the proceedings of a symposium, chaired and co-organized by Helene Raskin White and co-organized by Peter R. Giancola, that was presented at the 2002 RSA Meeting in San Francisco. The goal of this symposium was to integrate findings from methodologically divergent studies on the topic of alcohol-related aggression in humans. The investigators focused on isolating mediators and moderators of the alcohol-aggression relationship. Peter R. Giancola presented laboratory data demonstrating how alcohol's acute effects on aggression are moderated by individual difference and contextual factors. Mitchell E. Berman presented laboratory data on alcohol's acute effects on self-induced aggression. Helene Raskin White reviewed prospective data on how alcohol affects the intergenerational transmission of family violence. Stephen Chermack reviewed data on the impact of a family history of alcoholism and a family history of violence on the development of childhood behavioral problems and adult problems with drugs, alcohol, and violence. Finally, Kenneth E. Leonard presented data on personal and contextual factors influencing alcohol-related barroom violence.

Adult↗