Diana H. Fishbein

Impulsivity, aggression, and neuroendocrine responses to serotonergic stimulation in substance abusers.

Alterations in the activity of central serotonergic systems have been implicated in impulsive and aggressive behavior. We examined the neuroendocrine and psychological responses of 24 substance users with differing levels of aggressiveness and impulsivity to the oral administration of an indirect serotonin agonist fenfluramine (60 mg) or placebo given in a double-blind crossover design. All subjects were volunteers on a closed research ward and were abstinent from drugs for a minimum of 5 days. Baseline plasma prolactin (PRL) levels were greater in the groups with higher levels of self-reported aggressiveness and impulsivity. When adjusted for the baseline, PRL and cortisol responses 180 min after fenfluramine administration were significantly elevated in subjects with higher levels of aggressiveness and impulsivity. Peak cortisol levels were correlated with impulsivity. PRL and cortisol responses to fenfluramine were more strongly correlated with impulsivity than aggressiveness. Also, the more impulsive subjects reported a decrease in subjective states of depression, hostility and anxiety after drug treatment. These data further support the hypothesis of altered serotonergic activity in aggressive and impulsive behaviors.

Neuropsychological Function, Drug Abuse, and Violence: A Conceptual Framework

Delineation of the biological substrates of violence in substance abusers would be valuable in developing therapeutic interventions for substance abusers who tend to be refractory to conventional treatments. Substance abusers with chronically violent behavior show more severity and poorer prognosis of their substance abuse disorder and more criminal activity. Violence may share many of the same underlying mechanisms as substance abuse, given the comorbidity and commonalities in behavioral dimensions, including childhood and personality disorders with biological underpinnings. Neuropsychological dysfunction consistently characterizes both drug abuse and violence and may contribute to traits often cited as precursors to both, for example, impulsivity, poor decision-making ability, disinhibition, and inability to assess consequences. Deficits in executive cognitive functioning subserved specifically by the prefrontal cortex are implicated in substance abusers with violent behavior.

Executive cognitive functioning and aggression: a public health perspective

A large body of research from diverse fields suggests that impaired executive cognitive functioning (ECF) may play an important role in the etiology of aggression and violent behavior (AVB). A number of studies examining subjects without significant psychopathology has found compelling evidence for a relationship between subclinical impaired ECF and AVB. These findings provide an empirical foundation for research on the epidemiology of impaired ECF as a risk factor for AVB in the general population. Unfortunately, however, most research on the ECF-AVB relationship has been limited to clinical, incarcerated, and other small nonrepresentative samples of human subjects. Thus, little is known about the public health significance of impaired ECF and its implications for behavioral disorders. Research is reviewed that may shed light on the epidemiology of impaired ECF and its relationship to AVB. Other conditions that correlate with, define, or contribute to ECF impairments that may also relate to AVB are discussed. Because ECF is considered to be malleable, an introduction to interventions with potential to improve ECF and, in turn, AVB is included. Finally, an agenda, along with a conceptual framework to guide this work, is proposed for future research on the ECF-AVB relationship from a public health perspective, with attention to anticipated methodological and ethical challenges.

The importance of neurobiological research to the prevention of psychopathology.

There is both a biological and environmental component to the neural substrates for various forms of psychopathology. Brain dysfunction itself not only constitutes a formidable liability to psychopathology, but also has an impact on environmental and social responses to the individual, compounding the risk for an adverse outcome. Environmental conditions, such as social and physical stimulus deprivation, poverty, traumatic stress, and prenatal drug exposure, can further compromise brain function in the context of existing liabilities. The relationship between genetic and environmental processes is interactive, fluid, and cumulative in their ability to influence an individuals developmental trajectory and alter subsequent behavioral outcomes. Given the codependent relationship between these processes, brain function is now believed to be malleable via manipulations of the environment in ways that may decrease liability for psychopathology. Research that explores these relationships and ways in which interventions can redirect this developmental track may substantially advance both the science and practice of prevention. Studies attempting to isolate the neurobiological effects of socioenvironmental factors are reviewed, implications for intervention strategies are discussed, and a future research agenda is proposed to provide greater insight into specific brain-environment relationships. Armed with this knowledge, prevention scientists may eventually design programs that directly target these effects to reverse or attenuate negative outcomes.

Cognitive performance and autonomic reactivity in abstinent drug abusers and nonusers.

In this study the authors compared the performance of abstinent drug abusers (n = 21) and nonuser control participants (n = 20) in neurocognitive and emotional functions by use of the Rogers Decision Making Task, Gambling Task, Emotional Stroop, impulsivity continuous performance task (CPT), and vigilance CPT. Skin conductance (SC) and heart rate (HR) monitoring was synchronized with task performance. Groups showed similar performance for vigilance, impulsivity, and emotional interference; however, drug abusers showed stronger SC responses. Drug abusers performed more poorly on the Gambling and Rogers Decision Making Tasks. When making risky decisions, drug abusers showed significantly less increase in SC activity than controls and exhibited lower HRs throughout performance on all tasks. In conclusion, complex tasks involving decision making, sensitivity to consequences, and emotional regulation discriminated between drug abusers and controls.

Mediators of the Stress-Substance-Use Relationship in Urban Male Adolescents

Exposure to chronic or severe acute stressors throughout the lifespan has been linked with numerous negative behavioral, emotional, cognitive, and physical consequences. Adolescence is considered to be a particularly vulnerable period given that the brain is experiencing dramatic developmental change during this time. The present study examined a sample of adolescents (N=125) considered to be at high risk for stress exposures and drug use by virtue of their environment and low income levels to identify possible neurocognitive (i.e., impulsivity, delay of gratification, emotional perception, and risky decision-making) and social competency mechanisms that may mediate this relationship. Using Mplus, a mediational model was tested using full information maximum likelihood estimates. Risky decision-making and poor social competency skills were related to previous stressful experiences; however, only social competencies mediated the effect of stressors on reports of past year marijuana, alcohol, and polydrug use. As such, stress appears to exert its negative impact through alterations in abilities to generate and execute prosocial decisions and behaviors. Interventions that directly address the effects of stress on social competencies may be especially important for children who have experienced adversity including those exposed to parental divorce, parental psychopathology, neglect or abuse, parental death, and poverty.

Differential Relationships Between Personal and Community Stressors and Children’s Neurocognitive Functioning

Early adversity can alter development of neurocognition, including executive cognitive and emotional regulatory functions. This is the first study to explore differential relationships between personal (physical and emotional abuse and neglect, school and parental stressors) and community (neighborhood problems and witnessing neighborhood violence) stressors and neurocognition. Predominantly Latino children ( n = 553) aged 10 to 12 years completed tasks measuring intelligence, impulsivity, problem solving, cognitive flexibility, decision making, and emotion attributions. Adjusting for age and parent education, bivariate regression analyses found exposure to personal stressors to be associated with relative deficits in at least one neurocognitive function. Community stressors were related to relative deficits in emotion attributions and problem solving. In multivariate analyses, neglect was related to misattributions of emotion and IQ deficits, and physical abuse was related to problem solving. Community stressors were not correlated with neurocognition when viewed relative to personal stressors. Stressor types were differentially associated with performance on specific neurocognitive tasks.

Psychological correlates of frequency and type of drug use among jail inmates

The comorbidity of drug abuse and various forms of psychopathology is pervasive and well documented. In particular, the incidence of depression, anxiety, and antisocial personality disorder is high among substance abusers relative to non-drug abusers. Offender populations have a high rate of substance abuse, and some studies suggest that the incidence of psychopathology may be even greater than in other drug using groups. In order to identify specific types of psychopathology as they relate to drug preferences and frequency of use among drug-using offenders, arrestees at the Baltimore City Detention Center were examined. During extensive interviews, drug-abusing arrestees provided information pertaining to their backgrounds, childhood histories, biological relatives, present behaviors, and criminal and drug histories. Additionally, several psychological inventories were administered to evaluate the presence of depression, anxiety, psychopathy, and impulsivity. Results indicate that the frequency with which subjects reported using specific drugs and drug of choice were significantly associated with particular measures of psychopathology. A composite measure of psychopathy was especially related to the frequency of alcohol, marijuana, and cocaine use. Subjects who reported using cocaine on a frequent basis scored high on measures of hostility and reported committing more property crimes, while violent crimes were more likely to be reported by subjects scoring high on the measure of psychopathy. Other noteworthy findings will be discussed along with the limitations of this study.

Differential Susceptibility to Comorbid Drug Abuse and Violence

Although many psychoactive substances have been associated with violent behavior, only a subgroup manifests excessively aggressive behavior when sober or intoxicated. Theories to explain addictive behaviors in general may directly relate to the specific proclivity to exhibit excessive aggression in this subset of users. Certain personality traits and cognitive deficits coexist in individuals prone to both drug abuse and violence, suggesting a common origin. Because these excessive and compulsive behaviors have been linked with aberrations in the metabolism and activity of the neurotransmitters dopamine and serotonin, their origins may be partly genetic or biological. Alterations in neurotransmitter function influence activities within the brains reward center to perturb nervous system arousal levels, thereby increasing stimulation-seeking behaviors. Manifestations of these neurobiological aberrations can be measured in physiological and biochemical processes that serve to mediate these behavioral and psychological outcomes.

Infusing developmental neuroscience into school-based preventive interventions: implications and future directions.

PURPOSE Recent advances in developmental neuroscience have the potential to significantly impact the behavioral and academic outcomes of adolescents. By adopting a translational approach, we aim to promote the transfer of knowledge related to neurological, cognitive, and emotion regulatory factors that underlie youths ability to respond to educational and prevention programming. METHOD This article synthesizes basic and applied research from the field of developmental neuroscience to highlight the significance of this work for the creation, evaluation, and tailoring of school-based preventive interventions designed to address aggressive behavior problems. We draw on research related to stress, social-cognitive factors, emotional perception and regulation, and executive functioning to identify potential neurodevelopmental mediators and moderators of prevention program impacts. RESULTS Findings suggest that a high level of brain plasticity characterizes early childhood and adolescent stages of development, providing optimal windows of opportunity for intervention. The available research emphasizes the importance of executive functioning and related emotional regulatory factors as potential mechanisms for change in educational and risk prevention models. CONCLUSIONS Neuroscience research provides insights into underlying mechanisms that, when appropriately targeted, can help optimize the impact of social-emotional learning curricula. Recommendations are made for how to apply relevant findings from neuroscience and related disciplines to improve behavioral and academic outcomes for school-aged youth. Additional research areas are identified to inform the creation of neurodevelopmentally sensitive preventive interventions targeting aggressive behavior problems which, in turn, are expected to affect academic outcomes.