Aggression, impulsivity and serotonin in drug dependence

Aggression, impulsivity, and central serotonergic function were evaluated in two groups of human volunteers; one group having a history of substance dependence (DRUG+) and another group with no drug use history (DRUG$-$). The hypothesis was that DRUG+ subjects would be more aggressive, more impulsive, and have attenuated serotonergic function. Results showed that DRUG+ subjects behaved more aggressively in a computer paradigm of aggression and also reported more aggression on questionnaires than DRUG$-$ subjects. In a computer paradigm of impulsivity, the DRUG+ group showed a lesser ability to delay gratification than the DRUG$-$ group in the last session of testing. The DRUG+ subjects also reported more venturesomeness and problems associated with low impulse control on questionnaires. Serotonergic function was measured through the neuroendocrine and hypothermic response to an orally administered serotonin (5-HT) agonist specific to the 5-HT$\rm\sb{1A}$ receptor subtype (ipsapirone). The neuroendocrine responses did not differ between DRUG$\pm$ groups, indicating no difference in the sensitivity of the presynaptic or postsynaptic 5-HT$\rm\sb{1A}$ receptors. An unexpected result was that the indicator hormone, cortisol, was at a lower baseline level in the DRUG+ group than the DRUG$-$ group. Lowered cortisol levels have been previously noted in children at high risk foul antisociality and future drug use. A principal components analysis including impulsivity, aggression, and serotonergic function measures produced three unique factors. The factors, Antisocial Tendency and Self-Control and Serotonergic Function combined to produce a significant regression equation explaining 36% of variability in the DRUG$\pm$ groups. These factors included measures of aggression, impulsivity, mood, and educational attainment. These results suggest that the current measures of aggression and impulsivity were predictive of a drug dependence disorder but that neuroendocrine function is not yet a useful indicator of drug dependence status. ^

Proactive aggression: A two part study

Aggressive behavior can be divided into the subtypes: reactive and proactive. Reactive aggressive acts occur in response to a stimulus or provocation. Proactive aggressive acts occur without provocation and are goal-directed. A number of findings have suggested that individuals displaying proactive aggression may be discerned from individuals not displaying proactive aggression on measures of personality, psychopathology and psychopathy, as well as on aggressive histories and type and severity of aggressive behaviors committed. The current study was conducted in two phases; phase 1 and 2. This was because phase 1 compared proactive aggressive, reactive aggressive and non-aggressive subjects on questionnaire measures, while phase 2 observed the acute effects of the benzodiazepine alprazolam on only proactive aggressive subjects. The phase 1 hypotheses were that proactive aggressive subjects would show greater numbers of personality disorders and have greater psychopathy relative to reactive and non-aggressive subjects. To verify these hypotheses subjects were recruited from the community and classified as proactive (n = 20), reactive (n = 20) or non-aggressive (n = 10) via laboratory behavioral testing. Classified subjects were administered a battery of questionnaires pertaining to personality disorders (SCID-II, OMNI-IV), psychopathy (PCL-R) and aggression history. The results of these questionnaire measures were subjected to statistical analyses, which confirmed the hypotheses. In the second phase, the acute effects of three doses of the benzodiazepine alprazolam were evaluated in proactive aggressive subjects on proactive aggressive responding in the computer-based Point Subtraction Aggression Paradigm (PSAP). In phase 2 it was hypothesized that alprazolam would produce dose dependent decreases in aggressive responding. Subjects were never provoked in this phase, and aggressive responding was classified as proactive. Studies of drugs acting on the GABA system have frequently found decreases in aggression in animals and humans, although there have also been findings of increased (paradoxical) aggression. The hypothesis was tested by statistical analysis of proactive aggressive responding under placebo vs. under alprazolam. The hypothesis was supported by six of seven subjects. Aggressive responding was significantly, decreased under alprazolam relative to placebo in six subjects. One subject showed increases in aggressive responding.^

The Texas driver responsibility program: A preliminary analysis of the impact on impaired driving and trauma system funding

Objective. In 2003, the State of Texas instituted the Driver Responsibility Program (TDRP), a program consisting of a driving infraction point system coupled with a series of graded fines and annual surcharges for specific traffic violations such as driving while intoxicated (DWI). Approximately half of the revenues generated are earmarked to be disbursed to the state's trauma system to cover uncompensated trauma care costs. This study examined initial program implementation, the impact of trauma system funding, and initial impact on impaired driving knowledge, attitudes and behaviors. A model for targeted media campaigns to improve the program's deterrence effects was developed. ^ Methods. Data from two independent driver survey samples (conducted in 1999 and 2005), department of public safety records, state health department data and a state auditor's report were used to evaluate the program's initial implementation, impact and outcome with respect to drivers' impaired driving knowledge, attitudes and behavior (based on constructs of social cognitive theory) and hospital uncompensated trauma care funding. Survey results were used to develop a regression model of high risk drivers who should be targeted to improve program outcome with respect to deterring impaired driving. ^ Results. Low driver compliance with fee payment (28%) and program implementation problems were associated with lower surcharge revenues in the first two years ($59.5 million versus $525 million predicted). Program revenue distribution to trauma hospitals was associated with a 16% increase in designated trauma centers. Survey data demonstrated that only 28% of drivers are aware of the TDRP and that there has been no initial impact on impaired driving behavior. Logistical regression modeling suggested that target media campaigns highlighting the likelihood of DWI detection by law enforcement and the increased surcharges associated with the TDRP are required to deter impaired driving. ^ Conclusions. Although the TDRP raised nearly $60 million in surcharge revenue for the Texas trauma system over the first two years, this study did not find evidence of a change in impaired driving knowledge, attitudes or behaviors from 1999 to 2005. Further research is required to measure whether the program is associated with decreased alcohol-related traffic fatalities. ^

Examining the Relationship Between Media Use and Aggression, Sexuality, and Body Image

Objectives: The primary purpose of this research is to understand the media's impact on individual attitudes and behaviors related to aggression, sexuality, and body image. This research is of particular importance because it uses up-to-date data reflecting effects based on the current media environment. Additionally, it includes a racially diverse sample. Methods: A survey of 407 students at a large, public university was conducted. The survey instrument contained general measures related to media consumption, including overall television, video game, and internet use, as well as more specific questions related to particular types of media, such as pornography. For the dependent variables, questions were included that measured both attitudes and behaviors related to aggression, sexuality, and body image. Results: Consistent with predictions, media use impacted both attitudes and behaviors related to aggression, sexuality, and body image. Specifically, overall television consumption led to increased levels of aggression (r=.18, pr=.20, pr=.24, pr=.42, pr=.40, p Conclusions: The media continue to play an important role in the development of attitudes and behaviors. It is warranted, therefore, to continue to investigate what media can cause negative outcomes, as well as to determine how those outcomes vary based on race and gender.

Relationships of impulsivity and physical fighting history to alcohol -induced aggression in women

Research suggests women respond to the aggression-inducing effects of alcohol in a manner similar to men. Highly aggressive men are more prone to alcohol-induced aggression, but this relationship is less clear for women. This study examined whether alcohol consumption would differentially affect laboratory-measured aggression in a sample of aggressive and non-aggressive women and how those differences might be related to components of impulsive behavior. In 39 women recruited from the community (two groups: with and without histories of physical fighting) ages 21–40, laboratory aggressive behavior was assessed following placebo and 0.80 g/kg alcohol consumption (all women experienced both conditions). Baseline laboratory impulsive behavior of three impulsivity models was later assessed in the same women. In the aggression model (PSAP), participants were provoked by periodic subtractions of money, which were blamed on a fictitious partner. Aggression was operationalized as the responses the participant made to subtract money from that partner. The three components of impulsivity that were tested included: (1) response initiation (IMT/DMT), premature responses made prior to the completion of stimulus processing, (2) response inhibition (GoStop), a failure to inhibit an already initiated response, and (3) consequence sensitivity (SKIP and TCIP), the choice for a smaller-sooner reward over a larger-later reward. I hypothesized that, compared to women with no history of physical fighting, women with a history of physical fighting would exhibit higher rates of alcohol-induced laboratory aggression and higher rates of baseline impulsive responding (particularly for the IMT/DMT), which would also be related to the alcohol-induced increases aggression. Consistent with studies in men, the aggressive women showed strong associations between laboratory aggression and self-report measures, while the non-aggressive women did not. However, unlike men, following alcohol consumption it was the non-aggressive women's laboratory aggression that was related to their self-reports of aggression and impulsivity. Additionally, response initiation measures of impulsivity distinguished the two groups, while response inhibition and consequence sensitivity measures did not; commission error rates on the IMT/DMT were higher in the aggressive women compared to the non-aggressive women. Regression analyses of the behavioral measures showed no relationship between the aggression and impulsivity performance of the two groups. These results suggest that the behavioral (and potentially biological) mechanism underlying aggressive behavior of women is different than that of men. ^