The neurobiology of human aggressive behavior: Neuroimaging, genetic, and neurochemical aspects

In modern societies, there is a strive to improve the quality of life related to risk of crimes which inevitably requires a better understanding of brain determinants and mediators of aggression. Neurobiology provides powerful tools to achieve this end. Pre-clinical and clinical studies show that changes in regional volumes, metabolism-function and connectivity within specific neural networks are related to aggression. Subregions of prefrontal cortex, insula, amygdala, basal ganglia and hippocampus play a major role within these circuits and have been consistently implicated in biology of aggression. Genetic variations in proteins regulating the synthesis, degradation, and transport of serotonin and dopamine as well as their signal transduction have been found to mediate behavioral variability observed in aggression. Gene-gene and gene-environment interactions represent additional important risk factors for aggressiveness. Considering the social burden of pathological forms of aggression, more basic and translational studies should be conducted to accelerate applications to clinical practice, justice courts, and policy making.

Sex and age differences in risk factors of marijuana involvement during adolescence

Objectives

We aimed to examine whether there are sex and age differences in psychosocial risk factors of marijuana use during adolescence.

Methods

Data were drawn from 57,767 adolescents (8^th and 10^th graders) from the 2012-2013 Monitoring the Future study. We examined the association between socio-demographic and behavioral correlates with different frequencies of past-year marijuana use (non-use, occasional use: <10 time, frequent use: 10-39 times, and regular use: 40+ times). We further investigated whether these associations were similar for boys and girls of different ages.

Results

Overall, 20.6% of the adolescents reported past-year marijuana use: 12.1% occasional use, 4.3% frequent use, and 3.8% regular use. Girls were less likely to be frequent and regular marijuana users (frequent use: OR=0.83 [0.75, 0.93]; regular use: OR=0.41 [0.36, 0.48]) while no sex difference was noted for occasional use. Also, the odds of deviant behaviors were higher as the frequencies of marijuana use were higher. Compared to younger girls, older boys and girls had higher association between all levels of marijuana use and low self-esteem, low perceived harm, peer influence and perceived easy access. Besides, younger boys were more likely than younger girls to report an association between regular marijuana use with low self-esteem, peer influence, and perceived easy access but not with perceived low harm.

Conclusions/Importance

Findings suggest the relationship between these psychosocial correlates and frequency of marijuana involvement varies across sex and age groups. These variations ask for a nuanced approach to prevention of marijuana involvement in different groups of youth.

A Factor Analytic Model of Drug-Related Behavior in Adolescence and Its Impact on Arrests at Multiple Stages of the Life Course

OBJECTIVES

Recognizing the inherent variability of drug-related behaviors, this study develops an empirically-driven and holistic model of drug-related behavior during adolescence using factor analysis to simultaneously model multiple drug behaviors.

METHODS

The factor analytic model uncovers latent dimensions of drug-related behaviors, rather than patterns of individuals. These latent dimensions are treated as empirical typologies which are then used to predict an individual's number of arrests accrued at multiple phases of the life course. The data are robust enough to simultaneously capture drug behavior measures typically considered in isolation in the literature, and to allow for behavior to change and evolve over the period of adolescence.

RESULTS

Results show that factor analysis is capable of developing highly descriptive patterns of drug offending, and that these patterns have great utility in predicting arrests. Results further demonstrate that while drug behavior patterns are predictive of arrests at the end of adolescence for both males and females, the impacts on arrests are longer lasting for females.

CONCLUSIONS

The various facets of drug behaviors have been a long-time concern of criminological research. However, the ability to model multiple behaviors simultaneously is often constrained by data that do not measure the constructs fully. Factor analysis is shown to be a useful technique for modeling adolescent drug involvement patterns in a way that accounts for the multitude and variability of possible behaviors, and in predicting future negative life outcomes, such as arrests.

Methamphetamine Use and Violent Behavior: User Perceptions and Predictors

This study describes the extent to which methamphetamine users perceive that their methamphetamine use has resulted in violent behavior, and describes the level of self-reported prevalence of specific violent criminal behaviors irrespective of methamphetamine use. Predictors of these two violence-related indicators, in terms of potential correlates from substance use history, criminal history, and health risk domains are examined. Data are from extensive interviews of 350 methamphetamine users who received substance use treatment in a large California county. A majority (56%) perceived that their methamphetamine use resulted in violent behavior; 59% reported specific violent criminal behaviors. For more than half of those reporting violent criminal behavior, this behavior pattern began before methamphetamine initiation. Thus, for a subsample of methamphetamine users, violence may be related to factors other than methamphetamine use. Users' perceptions that their methamphetamine use resulted in violence appears strongest for those with the most severe methamphetamine-related problems, particularly paranoia.

Injection drug users' and their risk networks' experiences of and attitudes towards drug dealer violence in Baltimore, Maryland

BACKGROUND

A large portion of violence associated with drug use is due to drug dealing. These analyses sought to examine injection drug users' attitudes and experiences of drug dealer violence.

METHODS

The current study used the 18-month follow up data of STEP into Action (STEP) study, an HIV prevention intervention among drug injectors and their risk network members conducted in Baltimore, Maryland. Four scales assessed acceptability of drug dealer violence, willingness to talk to drug users about avoiding drug dealer violence, social norms about reporting drug dealer violence and intentions to report drug dealer violence to the police.

RESULTS

Many (44%) of the 373 participants reported witnessing drug dealers' acts of violence within the prior 6 months. Although the majority of participants disagreed with statements on the acceptability of dealers using violence, only a minority indicated that they would call the police if they observed dealer violence. Most participants indicated that they would be interested in talking to drug users about how to avoid violent dealers. Males were more likely to report that violence was acceptable, whereas African Americans were less likely to condone violence. Those who were homeless and had higher incomes were more likely to report witnessing drug dealer violence.

CONCLUSIONS

These results suggest that it may be feasible to train current and former drug users and their risk network members in methods to promote violence reduction among drug dealers.

The toxicology of homicide offenders and victims: A review

ISSUES

The toxicology of homicide offenders and victims, and homicide as a cause of death among psychoactive substance users.

APPROACH

Review of the toxicology of homicide, and homicide as a cause of death among psychoactive substance users.

KEY FINDINGS

A half or more of offenders are intoxicated by a psychoactive substance at the time of the homicide, with alcohol the most commonly reported substance. Levels of substances among victims are comparable with those seen among perpetrators. Among both offenders and victims, levels of substances far exceed population use. Among substance users, homicide specific mortality rates of substance users far exceed population rates. Reducing rates of alcohol and other drug consumption, at national and individual levels, can be expected to substantially reduce rates of, and risk for, homicide.

CONCLUSIONS AND IMPLICATIONS

Psychoactive substances are strongly associated with homicide. One of the major societal benefits that can be derived from active attempts to reduce alcohol and other drug use are reductions in homicide rates.

Looking Forward and Backward in Records for Risks among Homicidal Youth

To identify risks for commission of homicide, 26 convicted Homicidal Youth ( M age =14.9 yr., SD =1.4; n = 26; 1 girl, 25 boys) were matched with 26 Nonviolent Delinquents and 26 clinic-referred Controls. Youth were tracked backward 8 years ( M = 7.7 yr., SD =1.5) and forward 3 years ( M = 3.1 yr., SD =1.2) in records. Data analysis was Shao's bootstrapped logistic regression yielding area under the curve ( AUC) and odds ratios ( OR). Predictors of homicide were poorer executive function ( OR = 7.04e+40), violent family ( OR = 4.01e−16), and alcohol abuse ( OR = 7.33e−17; AUC=.97, 95% CI = .77−.99). From earlier studies, 101 Homicidal Youth and their Controls were reanalyzed similarly. Predictors were poorer executive function ( OR = 6.51), lower social maturity ( OR = 0.28), weapon possession ( OR = 26.10), and gang membership ( OR = 4.14; AUC= .98, 95% CI = .96−.99). Groups were combined, i.e., 26 and 101 Homicidal; 127 Homicidal Youth (7 girls, 120 boys) and their matched Controis were tracked in records. The predictor was poorer executive function ( OR= 3.34e−21; AUC = .98, 95% CI = .96−.97). When 127 Homicidal Youth were compared with 127 matched Nonviolent Delinquents, predictors were poorer executive function ( OR = 2.83e–02), weapon possession ( OR = 1.63e−10), lower social maturity ( OR= 1.15), and use of special education services ( OR = .94; AUC= .94, 95% CI= .37−.99).

Practitioner review: adolescent alcohol use disorders: assessment and treatment issues

BACKGROUND

Alcohol use disorders in adolescents are associated with significant morbidity and mortality. Over the past decade, there has been a burgeoning of research on adolescent alcohol use disorders.

METHODS

A summary of the alcohol assessment tools is provided, and randomized studies reviewed and synthesized to provide an overview of state of the art knowledge of treatment of adolescent alcohol use disorders. Animal models of addiction are also briefly reviewed, and the value of translational research approaches, using findings from basic studies to guide the design of clinical investigations, is also highlighted.

RESULTS

Comorbidity is the rule, not the exception in adolescent alcohol use disorders. Comprehensive assessment of psychiatric and other substance use disorders, trauma experiences, and suicidality is indicated in this population to optimize selection of appropriate clinical interventions. In terms of available investigated treatments for adolescents with alcohol use disorders, Multidimensional Family Therapy and group administered Cognitive Behavioral Therapies have received the most empirical support to date. There is a paucity of research on pharmacological interventions in this patient population, and no firm treatment recommendations can be made in this area.

CONCLUSIONS

Given the high rate of relapse after treatment, evaluation of combined psychosocial and pharmacological interventions, and the development of novel intervention strategies are indicated.

The contribution of specific causes of death to sex differences in mortality

OBJECTIVE

Men have higher mortality rates than women for most causes of death. This study was conducted to determine the contribution of specific causes of death to the sex difference in years of potential life lost (YPLL).

METHODS

The authors examined data from the National Health Interview Survey with linked mortality data through 1997. Using survival analysis estimates, a stochastic simulation model to simulate death events for cohorts of white, African American, and Latino adults was created.

RESULTS

YPLL from all causes were greater among men than women. Homicide, motor vehicle accidents, and suicide accounted for 33% of YPLL sex difference among whites, 36% among African Americans, and 52% among Latinos. For all three racial/ethnic groups, cardiovascular disease (principally ischemic heart disease) was the second largest contributor to the sex difference in YPLL (29% among whites, 23% among African Americans, and 25% among Latinos). Lung cancer was also important among whites and African Americans, accounting for 15% and 17% of the sex difference in YPLL from all causes, respectively.

CONCLUSIONS

Ischemic heart disease, lung cancer, and traumatic deaths account for as much as three-quarters of the excess YPLL among men, suggesting that a few modifiable behaviors such as the use of tobacco, alcohol.

Are clinical impressions of adolescent substance use accurate?

OBJECTIVE

To compare providers' impressions of adolescents' level of substance use with diagnostic classifications from a structured diagnostic interview.

METHODS

Secondary analysis of data was conducted from a validation study of the CRAFFT substance abuse screening test of 14- to 18-year-old medical clinic patients (n = 533) and their corresponding medical care providers (n = 109) at an adolescent clinic affiliated with a large tertiary care pediatric hospital. Medical care providers completed a form that recorded their clinical impressions of patients' level of alcohol and drug involvement (none, minimal, problem, abuse, dependence) and demographic characteristics. The form included brief diagnostic descriptions for each level of use. After the medical visit, patients completed the Adolescent Diagnostic Interview (ADI), a structured diagnostic interview that yields diagnoses of abuse and dependence according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). On the basis of their past 12 months of alcohol and drug use on the ADI interview, adolescents were classified into 5 mutually exclusive diagnostic groups. "None" was defined by no reported use of alcohol or drugs during the past year. "Minimal use" was defined as use of alcohol or drugs but no report of any substance-related problems. "Problem use" was defined as reporting 1 or more substance-related problems but no diagnosis of abuse or dependence. "Abuse" was defined by meeting any 1 of 4 DSM-IV diagnostic criteria for either alcohol or drug abuse but no diagnosis of dependence. "Dependence" was defined by meeting any 3 of 7 diagnostic criteria for either alcohol or drug dependence, with or without a diagnosis of abuse. Proportions were compared using Fisher exact test. Agreement was assessed with the weighted kappa, and these analyses were stratified by substance used (ie, alcohol vs drug) and demographic characteristics. Sensitivity, specificity, and positive and negative predictive values were calculated from 2 x 2 tables.

RESULTS

Compared with the criterion standard interview, providers identified significantly fewer patients with problem use and abuse and no patients with dependence. Of >100 patients whom the ADI classified with substance problem use, providers correctly identified 18. Of 50 patients who were classified with a diagnosis of alcohol or drug abuse, providers correctly identified 10. Of 36 patients who were classified with a diagnosis of alcohol or drug dependence, providers correctly identified none. For the 86 adolescents who were classified with a substance-related disorder (ie, abuse or dependence), providers' impressions were "none" (24.4%), "minimal use" (50%), "problem use" (15.1%), "abuse" (10.5%), and "dependence" (0%). There was only marginal agreement between providers' impressions and diagnoses related to alcohol use (kappa = .29), drug use (kappa = .31), and any substance use (kappa = .30). Kappa was not significantly affected by the patient's age, but it was by gender. Among boys, kappa was significantly higher for impressions of drug use versus alcohol use (kappa = .48 vs kappa = .27); and, among drug users, kappa was significantly higher among boys compared with girls (kappa = .48 vs kappa = .24). Kappa did not differ significantly across race/ethnicity subgroups, although there is a suggestive trend toward higher agreement for black non-Hispanic compared with white non-Hispanic adolescents (kappa = .35 vs kappa = .21). Kappa did not differ significantly on the basis of the visit type, but the size of this difference (kappa = .36 vs kappa = .24) suggests that the longer well-child visit yielded greater identification of substance-related pathology. Providers' impressions had a sensitivity of .63 for identifying use of alcohol or drugs. However, sensitivity was poor for identification of problem use (.14), abuse (.10), and dependence (0), whereas specificity and positive predictive values were high. Of the 86 adolescents with a diagnosis of abuse or dependence, 75.6% were correctly identified by providers as using substances; however, the level of use in 50% of these adolescents was reported by providers as minimal.

CONCLUSIONS

In this study, clinical impressions of adolescents' alcohol/drug involvement underestimated substance-related pathology. When providers thought that use was present, there was a very high likelihood that a problem or disorder existed. The use of structured screening devices would likely improve identification of adolescents with substance-related pathology in primary care settings and should be considered for use with all adolescent patients, rather than only those who are perceived to be at higher risk.

A cross-sectional study on expression of anger and factors associated with criminal recidivism in prisoners with prior offences

OBJECTIVE

The purpose of this study is to determine demographical characteristics leading to crime recidivism and define anger levels and anger expression manners for those who re-commit crime.

METHOD

All the literate inmates in Izmit Closed Penitentiary were included in this cross-sectional study. The prisoners were asked to respond to State-Trait Anger Expression Inventory. Their socio-demographic data were collected and a questionnaire was given to them to determine their state of imprisonment, sentence, nature of the crime in which they were involved, their criminal history, their relationship with inmates and prison staff and substance and alcohol use.

RESULTS

Of the 438 prisoners, 302 (68.9%) responded to the questionnaires. Crime recidivism among the study cohort was observed to be 37.4%. Mean trait anger, anger out and anger in scores were significantly higher in prisoners with criminal recidivism in comparison with those who did not have prior criminal records. However, mean anger control scores for prisoners with or without criminal recidivism were similar. Unemployment, education level completed at secondary school or below, having committed a crime under the influence of alcohol or narcotics, having been involved in prison fights, having resisted police officers, caused damage in their vicinity when angry and violent crimes were all found to be possible causes of criminal recidivism. Educational level completed at secondary school or below, getting into fights with other prisoners, unemployment and resisting police officers were determined to be the strongest indicators to predict criminal recidivism when all variables were considered according to a logistic regression model.

CONCLUSION

It can be proposed that those who have problems with officials or hostile towards others constitute a risk group for criminal recidivism. If prisoners with criminal recidivism can be helped to identify and control their anger, their risk of committing a new crime can be minimised.