ADHD and delinquency--a developmental perspective

Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent psychiatric disorders of childhood and adolescence. Until now, it has been unclear whether ADHD by itself constitutes a risk factor for later delinquency or does so only in combination with other disruptive symptoms. This article seeks to give a comprehensive account of the literature to shed light on the developmental pathway from childhood ADHD to adult criminality. Comorbid ADHD and conduct disorder (CD) are significantly related to a range of biological and environmental risk factors such as neurocognitive impairment, high parental psychopathology, poor social functioning, and other comorbid mental disorders, particularly substance abuse, that are described in this review. In addition, the results of treatment studies are presented, with a special focus on the results of the Multimodal Treatment Study of Children with ADHD (MTA). Although treatment programs, including medication and psychosocial treatment, can be very effective in improving the functioning of children with ADHD in the social and academic domains in the short term, there is no conclusive evidence that such treatments lower the risk for developing delinquency in adulthood.

Age-Related Changes in Heritability of Behavioral Phenotypes Over Adolescence and Young Adulthood: A Meta-Analysis

The relative proportions of genetic and environmental variance in behavioral measures have been studied extensively. A growing body of literature has examined changes in heritability measures over time, but we are unaware of any prior efforts to assess developmental heritability changes for multiple behavioral phenotypes using multiple data sources. We have chosen to explore the proportional genetic influences on a variety of behaviors during the genetically and environmentally labile adolescent and young adult years. This meta-analysis examined 8 behavioral domains and incorporated only primary research articles reporting two or more heritability time points in order to minimize the age-to-age error variability. Linear regression analyses revealed significant cross-time heritability increases for externalizing behaviors, anxiety symptoms, depressive symptoms, IQ, and social attitudes and nonsignificant increases for alcohol consumption, and nicotine initiation, but no evidence of heritability changes for attention-deficit/hyperactivity disorder. A variety of mechanisms may underlie these findings including the rising importance of active genotype-environment correlation, an increase in gene expression, or proportional reductions in environmental variance. Additional longitudinal studies and the inclusion of measures of total variance in primary research reports will aid in distinguishing between these possibilities. Further studies exploring heritability changes beyond young adulthood would also benefit our understanding of factors influencing heritability of behavioral traits over the lifespan.

Impact of fathers on risky sexual behavior in daughters: A genetically and environmentally controlled sibling study

Girls receiving lower quality paternal investment tend to engage in more risky sexual behavior (RSB) than peers. Whereas paternal investment theory posits that this effect is causal, it could arise from environmental or genetic confounds. To distinguish between these competing explanations, the current authors employed a genetically and environmentally controlled sibling design (N = 101 sister pairs; ages 18–36), which retrospectively examined the effects of differential sibling exposure to family disruption/father absence and quality of fathering. Consistent with a causal explanation, differences between older and younger sisters in the effects of quality of fathering on RSB were greatest in biologically disrupted families when there was a large age gap between the sisters (thus maximizing differential exposure to fathers), with greater exposure within families to higher quality fathering serving as a protective factor against RSB. Further, variation around the lower end of fathering quality appeared to have the most influence on RSB. In contrast, differential sibling exposure to family disruption/father absence (irrespective of quality of fathering) was not associated with RSB. The differential sibling-exposure design affords a new quasi-experimental method for evaluating the causal effects of fathers within families.

Genetically influenced change in sensation seeking drives the rise of delinquent behavior during adolescence

Sensation seeking is associated with an increased propensity for delinquency, and emerging research on personality change suggests that mean levels of sensation seeking increase substantially from childhood to adolescence. The current study tested whether individual differences in the rate of change of sensation seeking predicted within-person change in delinquent behavior and whether genetically influenced differences in rate of personality change accounted for this association. Sensation seeking and delinquent behavior were assessed biennially between ages 10-11 and 16-17 in a nationally representative sample of 7675 youths from the National Longitudinal Study of Youth: Children and Young Adults (CNLSY). Analyses using latent growth curve modeling found that within-person change in sensation seeking was significantly and positively correlated with within-person change in delinquency from childhood to adolescence. Furthermore, behavioral genetic analyses of a subset of 2562 sibling pairs indicated that there were substantial genetic influences on both initial levels of sensation seeking and change in sensation seeking during early adolescence, with over 80% of individual differences in change due to genetic factors. Finally, these genetically driven increases in sensation seeking were most important for predicting increases in delinquency, whereas environmental paths between sensation seeking and delinquency were not significant. These results suggest that developmental changes in delinquent behaviors during adolescence are driven by a genetically governed process of personality change.

Attention deficit hyperactivity disorder and obsessive-compulsive disorder among former heroin addicts currently in methadone maintenance treatment

BACKGROUND

The aim of this study was to evaluate the prevalence of childhood and adulthood attention deficit hyperactivity disorder (ADHD) and clinical obsessive-compulsive disorder (OCD) among adult patients in methadone maintenance treatment (MMT) and to characterize possible risk factors.

SAMPLING AND METHODS

A random sample of 154 current MMT patients was studied for childhood ADHD (Wender Utah Rating Scale), current clinical OCD (Yale-Brown Obsessive Compulsive Scale), lifetime trauma history and modified Addiction Severity Index for demographics, as well as any lifetime DSM-IV-TR psychiatric diagnosis.

RESULTS

Fifty-one patients (33.1%) had childhood ADHD, and more of this group currently had clinical OCD compared to patients who did not have childhood ADHD (55.3 vs. 30.1%). The two groups did not differ with regard to gender and age of admission to MMT. Logistic regression found that the childhood ADHD group had a higher risk of having OCD [odds ratio (OR) 3.8, 95% confidence interval (CI) 1.6-8.8], more severe nicotine smoking (OR 1.4, 95% CI 1.1-1.7) and fewer years of education (OR 0.8, 95% CI 0.6-1) and were more likely to have a DSM-IV-TR axis II disorder (OR 4.3, 95% CI 1.4-13.4) and a history of falls (OR 4.3, 95% CI 1.4-12.9).

CONCLUSIONS

Although ADHD is more prevalent among males in the general population, the rates in our MMT population were similar in each gender. One third of our sample had suffered from ADHD during childhood, which may have led them to self-medicate with drugs and thus to addiction. Childhood ADHD was associated with current OCD, and both conditions were highly prevalent among our MMT patients. The reason for a history of repeated falls warrants further study.

Observed externalizing behavior: a developmental comparison of genetic and environmental influences across three samples

Estimates of genetic and environmental influences on externalizing behavior are markedly inconsistent. In an attempt to refine and extend our knowledge of externalizing behavior, the current study examined the etiology of externalizing behavior using observational data in middle childhood and adolescence from three twin and sibling samples. Observational ratings offer a unique perspective on externalizing behavior rarely examined within behavioral genetic designs. Shared environmental influences were significant and moderate to large in magnitude across all three samples (i.e., 44, 77, and 38%), while genetic influences (31%) were significant only for the adolescent sample. All three samples showed greater shared environmental influences and less genetic influence than is typically found when examining self-, parent-, and teacher-reports of externalizing behavior. These findings are consistent with other reports that have found evidence for shared environmental influences on measures of child externalizing behavior-in direct contrast to a commonly held perception that shared environmental factors do not have significant influences on behavior beyond early childhood.

Dopaminergic system genes in childhood aggression: possible role for DRD2

Excessive or deficient levels of extracellular dopamine have been hypothesized to contribute to a broad spectrum of mood, motor, and thought abnormalities, and dopaminergic system genes have been implicated in aggressive behaviour from animal and human studies. OBJECTIVE. We examined selected members of the dopaminergic system genes for association with child aggression.

METHOD

We analyzed polymorphisms in the dopamine transporter DAT1/SLC6A3, dopamine receptor DRD2, and DRD4 genes in our sample of pervasive childhood aggression consisting of 144 cases paired with 144 healthy controls, matched for sex and ethnicity.

RESULTS

Aggressive children were significantly more likely to have the at least one copy of the G allele for the DRD2 A-241G polymorphism (genotypic P=0.02; allelic P=0.01). The DRD2 rs1079598 CC genotype was overrepresented in aggressive children compared to controls (genotype P=0.04). The DRD2 TaqIA T allele (P=0.01) and the TT genotype (P=0.01) were also significantly overrepresented in aggressive children.

CONCLUSIONS

Our preliminary results suggest that three polymorphisms in DRD2 are associated with childhood aggression. Future studies are required to replicate the current results and to further explore the relationship between the dopamine system and aggressive behaviour in children.

Expanding our lens: female pathways to antisocial behavior in adolescence and adulthood

Women and girls' engagement in antisocial behavior represents a psychological issue of great concern given the radiating impact that women's antisociality can have on individuals, families, and communities. Despite its importance and relevance for psychological science, this topic has received limited attention to date and no systematic review of risk factors exists. The present paper aims to systematically review the empirical literature informing risk factors relevant to women's antisocial behavior, with a focus on adolescence and adulthood. Primary aims are to 1) review empirical literatures on risk factors for female antisocial behavior across multiple levels of influence (e.g., person-level characteristics, risky family factors, and gender-salient contexts) and fields of study (e.g., psychology, sociology); 2) evaluate the relevance of each factor for female antisocial behavior; and 3) incorporate an analysis of how gender at both the individual and ecological levels shapes pathways to antisocial behavior in women and girls. We conclude that women's antisocial behavior is best-understood as being influenced by person-level or individual vulnerabilities, risky family factors, and exposure to gender-salient interpersonal contexts, and underscore the importance of examining women's antisocial behavior through an expanded lens that views gender as an individual level attribute as well as a social category that organizes the social context in ways that may promote engagement in antisocial behavior. Based on the present systematic review, an integrative pathway model is proposed toward the goal of synthesizing current knowledge and generating testable hypotheses for future research.

Environmental factors associated with adolescent antisocial behavior in a poor urban community in Brazil

BACKGROUND

Investigating risk factors for anti-social behavior (ASB) is particularly relevant in a poor urban and violent community of a developing country where homicide is the primary cause of death among 15-24-year olds.

OBJECTIVES

To identify individual and environmental factors associated with ASB in adolescents from an urban poor community in the outskirts of São Paulo City, Brazil.

METHOD

This cross-sectional study was based on a probabilistic sample of clusters that included all eligible households (women aged 15-49 years with a son or daughter <18 years of age). One mother-child pair was randomly selected per household (n = 813; response rate: 82.4%). This study is focused on the age group 11-17 years (n = 248). ASB was identified by externalizing scores in the clinical range on the Child Behavior Checklist and/or the Youth Self Report. Potential correlates included individual, maternal, paternal, and familial characteristics. Backward logistic regression analysis identified independent correlates and significant interactions.

FINDINGS

Youths with high ASB scores were more likely to be victims of severe physical punishment and have an absent father/substitute. Maternal anxiety/depression was a risk factor only among older adolescents (15-17 years), while the presence of internalizing problems was a risk factor only among younger adolescents (11-14 years). Having a non-working mother increased the risk for ASB only among low-income adolescents.

CONCLUSION

The recognition that certain environmental factors may have harmful effects on adolescents' mental health, and the identification of more vulnerable groups can contribute to the development of effective strategies for prevention and treatment of ASB.

Examining the relationship between religiosity and self-control as predictors of prison deviance

The relationship between religiosity and crime has been the subject of much empirical debate and testing over the past 40 years. Some investigators have argued that observed relationships between religion and crime may be spurious because of self-control, arousal, or social control factors. The present study offers the first investigation of religiosity, self-control, and deviant behavior in the prison context. We use survey data from a sample of 208 recently paroled male inmates to test the impact of religiosity and self-control on prison deviance. The results indicate that two of the three measures of religiosity may be spurious predictors of prison deviance after accounting for self-control. Participation in religious services is the only measure of religiosity to significantly reduce the incidence of prison deviance when controlling for demographic factors, criminal history, and self-control. We conclude with implications for future studies of religiosity, self-control, and deviance in the prison context.

Genomic architecture of aggression: rare copy number variants in intermittent explosive disorder

Copy number variants (CNVs) are known to be associated with complex neuropsychiatric disorders (e.g., schizophrenia and autism) but have not been explored in the isolated features of aggressive behaviors such as intermittent explosive disorder (IED). IED is characterized by recurrent episodes of aggression in which individuals act impulsively and grossly out of proportion from the involved stressors. Previous studies have identified genetic variants in the serotonergic pathway that play a role in susceptibility to this behavior, but additional contributors have not been identified. Therefore, to further delineate possible genetic influences, we investigated CNVs in individuals diagnosed with IED and/or personality disorder (PD). We carried out array comparative genomic hybridization on 113 samples of individuals with isolated features of IED (n = 90) or PD (n = 23). We detected a recurrent 1.35-Mbp deletion on chromosome 1q21.1 in one IED subject and a novel ∼350-kbp deletion on chromosome 16q22.3q23.1 in another IED subject. While five recent reports have suggested the involvement of an ∼1.6-Mbp 15q13.3 deletion in individuals with behavioral problems, particularly aggression, we report an absence of such events in our study of individuals specifically selected for aggression. We did, however, detect a smaller ∼430-kbp 15q13.3 duplication containing CHRNA7 in one individual with PD. While these results suggest a possible role for rare CNVs in identifying genes underlying IED or PD, further studies on a large number of well-characterized individuals are necessary.

The Effects of Differential Parenting on Sibling Differences in Self-Control and Delinquency Among Brother–Sister Pairs

Gottfredson and Hirschi acknowledge that there are sex differences in levels of self-control, with males exhibiting lower levels of self-control compared to females. There remains a gap in the empirical literature, however, as to whether differential parental treatment can explain differences in levels of self-control across the sexes. Using siblings of opposite sex from the Add Health study ( N = 356, brother–sister pairs) and following a within-family research design, the current study examines whether differences in parenting behaviors within the home are associated with sex differences in self-control between siblings and whether these differences in self-control explained sex differences in delinquency. The results revealed that differential maternal attachment and differential maternal rejection were significantly related to sex differences in self-control. Sex differences in self-control, in turn, were significantly associated with sex differences in delinquency. The findings also showed that sex differences in self-control mediated the association between differential maternal rejection and delinquency, but that differential maternal attachment was indirectly associated with higher levels of delinquency for boys via lower levels of self-control. The impact of nonshared environmental factors on behavioral differences in opposite-sex siblings within the home is discussed.

Reduced cortical gray matter volume in male adolescents with substance and conduct problems

Boys with serious conduct and substance problems (Antisocial Substance Dependence (ASD)) repeatedly make impulsive and risky decisions in spite of possible negative consequences. Because prefrontal cortex (PFC) is involved in planning behavior in accord with prior rewards and punishments, structural abnormalities in PFC could contribute to a person's propensity to make risky decisions.

METHODS

We acquired high-resolution structural images of 25 male ASD patients (ages 14-18 years) and 19 controls of similar ages using a 3T MR system. We conducted whole-brain voxel-based morphometric analysis (p<0.05, corrected for multiple comparisons at whole-brain cluster-level) using Statistical Parametric Mapping version-5 and tested group differences in regional gray matter (GM) volume with analyses of covariance, adjusting for total GM volume, age, and IQ; we further adjusted between-group analyses for ADHD and depression. As secondary analyses, we tested for negative associations between GM volume and impulsivity within groups and separately, GM volume and symptom severity within patients using whole-brain regression analyses.

RESULTS

ASD boys had significantly lower GM volume than controls in left dorsolateral PFC (DLPFC), right lingual gyrus and bilateral cerebellum, and significantly higher GM volume in right precuneus. Left DLPFC GM volume showed negative association with impulsivity within controls and negative association with substance dependence severity within patients.

CONCLUSIONS

ASD boys show reduced GM volumes in several regions including DLPFC, a region highly relevant to impulsivity, disinhibition, and decision-making, and cerebellum, a region important for behavioral regulation, while they showed increased GM in precuneus, a region associated with self-referential and self-centered thinking.

Genetic and environmental influences on impulsivity: a meta-analysis of twin, family and adoption studies

A meta-analysis of twin, family and adoption studies was conducted to estimate the magnitude of genetic and environmental influences on impulsivity. The best fitting model for 41 key studies (58 independent samples from 14 month old infants to adults; N=27,147) included equal proportions of variance due to genetic (0.50) and non-shared environmental (0.50) influences, with genetic effects being both additive (0.38) and non-additive (0.12). Shared environmental effects were unimportant in explaining individual differences in impulsivity. Age, sex, and study design (twin vs. adoption) were all significant moderators of the magnitude of genetic and environmental influences on impulsivity. The relative contribution of genetic effects (broad sense heritability) and unique environmental effects were also found to be important throughout development from childhood to adulthood. Total genetic effects were found to be important for all ages, but appeared to be strongest in children. Analyses also demonstrated that genetic effects appeared to be stronger in males than in females. Method of assessment (laboratory tasks vs. questionnaires), however, was not a significant moderator of the genetic and environmental influences on impulsivity. These results provide a structured synthesis of existing behavior genetic studies on impulsivity by providing a clearer understanding of the relative genetic and environmental contributions in impulsive traits through various stages of development.

The genetic etiology of inhibitory control and behavior problems at 24 months of age

BACKGROUND

To investigate links between inhibitory control (IC) and behavior problems in early childhood, as well as genetic and environmental covariances between these two constructs.

METHODS

Parent and laboratory ratings of IC and parent ratings of externalizing and attention deficit hyperactivity disorder behaviors were administered at 24 months of age on a sample of 291 same-sex twin pairs (131 monozygotic, 160 dizygotic).

RESULTS

There were significant phenotypic associations between both IC assessments and the two areas of behavioral maladjustment (correlations ranged from -.13 to -.57). Multivariate analyses revealed that phenotypic covariance between IC and behavior problems could be substantially explained by common genetic influences (genetic correlations ranged from -.30 to -.74). Parent ratings of IC showed higher phenotypic and genetic correlations with behavior problems than lab ratings of IC.

CONCLUSIONS

This study is the first to examine the etiology of the covariance between IC and related behavioral difficulties in toddlerhood. Findings suggest that low levels of IC can be considered a genetic risk factor for the development of early emerging behavior problems.

Unpacking links between fathers' antisocial behaviors and children's behavior problems: direct, indirect, and interactive effects

Building upon previous evidence for the intergenerational transmission of antisocial behaviors, this research assessed and compared three models seeking to explain links between fathers' antisocial behaviors and children's behavior problems. A representative sample of children from low-income families (N=261) was followed from age 3 through age 9. Lagged OLS regression models assessed both short-term (1½  years) and longer-term (5½  years) prospective links between fathers' antisocial behaviors and children's behavior problems. Results supported a direct effects model: fathers' antisocial behaviors predicted growth in children's externalizing and internalizing behavior problems, with links stronger among resident-father families. Limited evidence of indirect effects emerged, with links between fathers' antisocial behaviors and children's behavior problems only slightly attenuated controlling for related risk factors and for parenting quality, showing limited evidence of mediation. A new interactive model was proposed and supported, with high levels of harsh discipline exacerbating negative links between fathers' antisocial behaviors and children's internalizing problems. Results suggest caution in policies and programs which seek to universally increase marriage or father involvement without attention to fathers' behaviors.

Association of ADAM10 and CAMK2A polymorphisms with conduct disorder: evidence from family-based studies

Twin and family studies have shown that genetic factors play a role in the development of conduct disorder (CD). The purpose of this study was to identify genetic variants associated with CD using a family-based association study. We used 4,720 single nucleotide polymorphisms (SNPs) from the Illumina Panel and 11,120 SNPs from the Affymetrix 10K GeneChips genotyped in 155 Caucasian nuclear families from Genetic Analysis Workshop (GAW) 14, a subset from the Collaborative Study on the Genetics of Alcoholism (COGA). 20 SNPs had suggestive associations with CD (p<10(-3)), nine of which were located in known genes, including ADAM10 (rs383902, p=0.00036) and CAMK2A (rs2053053, p=0.00098). Our results were verified using the International Multi-Center ADHD Genetics Project (IMAGE) dataset. In conclusion, we identified several loci associated with CD. Especially, the two genes (ADAM10 and CAMK2A) have been reported to be associated with Alzheimer's disease, bipolar disorder and depression. These findings may serve as a resource for replication in other populations.

Reduced cortical inhibition in violent offenders: a study with transcranial magnetic stimulation

BACKGROUND

Aggression and violent behaviour are often regarded as a threat to society. Therefore, understanding violent behaviour has high social relevance. We performed a study with transcranial magnetic stimulation on a sample of violent offenders in order to measure cortical inhibition in the motor neuron system that is part of the frontal cortex.

METHODS

To investigate intracortical inhibition and intracortical facilitation, we conducted paired-pulse stimulation according to the technique of Kujirai and his group (see Method). The investigation sample comprised 62 right-handers: 32 prisoners who had committed severe violent crimes and 30 controls with no history of violence. All subjects were male and matched for age.

RESULTS

Using the paired-pulse paradigm with interstimulus intervals (ISI) of 1-15 ms, a reduced cortical inhibition (ISI: 3 ms) was found in the left cortex of violent offenders compared with control subjects.

CONCLUSIONS

These findings corroborate the hypothesis of inhibition deficits and frontal cortex dysfunction in violent offenders when compared with non-violent control subjects.

Gene-environment processes linking aggression, peer victimization, and the teacher-child relationship

Aggressive behavior in middle childhood is at least partly explained by genetic factors. Nevertheless, estimations of simple effects ignore possible gene-environment interactions (G × E) or gene-environment correlations (rGE) in the etiology of aggression. The present study aimed to simultaneously test for G × E and rGE processes between aggression, on the one hand, and peer victimization and the teacher-child relationship in school, on the other hand. The sample comprised 124 MZ pairs and 93 DZ pairs assessed in Grade 1 (mean age = 84.7 months). Consistent with rGE, children with a presumed genetic disposition for aggression were at an increased risk of peer victimization, whereas in line with G × E, a positive relationship with the teacher mitigated the genetically mediated expression of aggression.

Genetic determinants of aggression and impulsivity in humans

Human aggression/impulsivity-related traits have a complex background that is greatly influenced by genetic and non-genetic factors. The relationship between aggression and anxiety is regulated by highly conserved brain regions including amygdala, which controls neural circuits triggering defensive, aggressive, or avoidant behavioral models. The dysfunction of neural circuits responsible for emotional control was shown to represent an etiological factor of violent behavior. In addition to the amygdala, these circuits also involve the anterior cingulated cortex and regions of the prefrontal cortex. Excessive reactivity in the amygdala coupled with inadequate prefrontal regulation serves to increase the likelihood of aggressive behavior. Developmental alterations in prefrontal-subcortical circuitry as well as neuromodulatory and hormonal abnormality appear to play a role. Imbalance in testosterone/serotonin and testosterone/cortisol ratios (e.g., increased testosterone levels and reduced cortisol levels) increases the propensity toward aggression because of reduced activation of the neural circuitry of impulse control and self-regulation. Serotonin facilitates prefrontal inhibition, and thus insufficient serotonergic activity can enhance aggression. Genetic predisposition to aggression appears to be deeply affected by the polymorphic genetic variants of the serotoninergic system that influences serotonin levels in the central and peripheral nervous system, biological effects of this hormone, and rate of serotonin production, synaptic release and degradation. Among these variants, functional polymorphisms in the monoamine oxidase A (MAOA) and serotonin transporter (5-HTT) may be of particular importance due to the relationship between these polymorphic variants and anatomical changes in the limbic system of aggressive people. Furthermore, functional variants of MAOA and 5-HTT are capable of mediating the influence of environmental factors on aggression-related traits. In this review, we consider genetic determinants of human aggression, with special emphasis on genes involved in serotonin and dopamine metabolism and function.

Right anterior cingulate cortical thickness and bilateral striatal volume correlate with child behavior checklist aggressive behavior scores in healthy children

BACKGROUND

The anterior cingulate cortex (ACC), orbitofrontal cortex (OFC), and basal ganglia have been implicated in pathological aggression. This study aimed at identifying neuroanatomical correlates of impulsive aggression in healthy children.

METHODS

Data from 193 representative 6- to 18-year-old healthy children were obtained from the National Institutes of Health Magnetic Resonance Imaging Study of Normal Brain Development after a blinded quality control. Cortical thickness and subcortical volumes were obtained with automated software. Aggression levels were measured with the Aggressive Behavior scale (AGG) of the Child Behavior Checklist. AGG scores were regressed against cortical thickness and basal ganglia volumes using first- and second-order linear models while controlling for age, gender, scanner site, and total brain volume. Gender by AGG interactions were analyzed.

RESULTS

There were positive associations between bilateral striatal volumes and AGG scores (right: r = .238, p = .001; left: r = .188, p = .01). A significant association was found with right ACC and subgenual ACC cortical thickness in a second-order linear model (p < .05, corrected). High AGG scores were associated with a relatively thin right ACC cortex. An AGG by gender interaction trend was found in bilateral OFC and ACC associations with AGG scores.

CONCLUSIONS

This study shows the existence of relationships between impulsive aggression in healthy children and the structure of the striatum and right ACC. It also suggests the existence of gender-specific patterns of association in OFC/ACC gray matter. These results may guide research on oppositional-defiant and conduct disorders.

Selfishness and altruism can coexist when help is subject to diminishing returns

Altruism and selfishness are 30-50% heritable in man in both Western and non-Western populations. This genetically based variation in altruism and selfishness requires explanation. In non-human animals, altruism is generally directed towards relatives, and satisfies the condition known as Hamilton's rule. This nepotistic altruism evolves under natural selection only if the ratio of the benefit of receiving help to the cost of giving it exceeds a value that depends on the relatedness of the individuals involved. Standard analyses assume that the benefit provided by each individual is the same but it is plausible in some cases that as more individuals contribute, help is subject to diminishing returns. We analyse this situation using a single-locus two-allele model of selection in a diploid population with the altruistic allele dominant to the selfish allele. The analysis requires calculation of the relationship between the fitnesses of the genotypes and the frequencies of the genes. The fitnesses vary not only with the genotype of the individual but also with the distribution of phenotypes amongst the sibs of the individual and this depends on the genotypes of his parents. These calculations are not possible by direct fitness or ESS methods but are possible using population genetics. Our analysis shows that diminishing returns change the operation of natural selection and the outcome can now be a stable equilibrium between altruistic and selfish alleles rather than the elimination of one allele or the other. We thus provide a plausible genetic model of kin selection that leads to the stable coexistence in the same population of both altruistic and selfish individuals. This may explain reported genetic variation in altruism in man.

Maternal characteristics predicting young girls' disruptive behavior

Little is known about the relative predictive utility of maternal characteristics and parenting skills on the development of girls' disruptive behavior. The current study used five waves of parent- and child-report data from the ongoing Pittsburgh Girls Study to examine these relationships in a sample of 1,942 girls from age 7 to 12 years. Multivariate generalized estimating equation analyses indicated that European American race, mother's prenatal nicotine use, maternal depression, maternal conduct problems prior to age 15, and low maternal warmth explained unique variance. Maladaptive parenting partly mediated the effects of maternal depression and maternal conduct problems. Both current and early maternal risk factors have an impact on young girls' disruptive behavior, providing support for the timing and focus of the prevention of girls' disruptive behavior.

Treating persistent adolescent aggression

Adolescent aggressive behavior is a frequently encountered problem for clinicians and society as a whole. Better understanding of biological, social, and familial risk factors for maladaptive aggressive behavior may lead to more effective interventions. The social information processing problems characteristic of this group interfere with treatment and outcome. Although further studies are needed, evidence for the effectiveness of psychopharmacologic treatments is increasing. There is also evidence for several effective psychotherapeutic interventions, especially for those with affective/impulsive aggression. Knowledge of risk factors, psychosocial strategies, and psychopharmacologic treatments can enhance the clinician's ability to intervene with this difficult group.

Gender differences in trait aggression in young adults with drug and alcohol dependence compared to the general population

OBJECTIVE

Data in gender differences in aggression among alcohol and drug dependent subjects are lacking, and no published data are available about gender differences among various subtypes of substance using populations. The goal of this cross-sectional study was to investigate gender differences with regard to types of trait aggression in substance dependent young populations (age: 20-35 years) compared to the general population.

METHODS

Subjects were selected from two clinical samples with a diagnosis of alcohol and drug dependence as well as from a representative sample of the general population. Trait aggression was measured by the four individual subscales of the Buss Perry Aggression Questionnaire (physical-PA, verbal aggression-VA, hostility-H and anger AN) whereas alcohol and drug use were characterized by the AUDIT and EuroADAD scales, respectively.

RESULTS

Alcohol and drug dependent subjects showed higher severity on all four subscales of trait aggression compared to the general population. The male-female difference was the highest in the cannabis group. General Linear Model analysis for PA indicated a significant main effect of gender (higher PA for males, p=0.034) with no interaction between substance dependence and gender. For VA, no main effect or interaction for gender was found. Effect sizes for gender difference indicated that while males and females were similar in the control group in the severity in H and A, the level of H and AN was substantially higher in females than in males in the clinical group. These differences between the two genders reached statistical significance in the marijuana group, where female subjects showed a significantly higher severity in these two domains.

CONCLUSIONS

Compared to the normal sample chronic substance use is associated with higher scores on certain factors of trait aggression, including hostility and anger, in females than in males. Our data suggest that aggression in substance dependent females is more provocable by chronic use of alcohol and drugs than in males.

Parental depression and offspring psychopathology: a children of twins study

BACKGROUND

Associations between parental depression and offspring affective and disruptive disorders are well documented. Few genetically informed studies have explored the processes underlying intergenerational associations.

METHOD

A semi-structured interview assessing DSM-III-R psychiatric disorders was administered to twins (n=1296) from the Australian Twin Register (ATR), their spouses (n=1046) and offspring (n=2555). We used the Children of Twins (CoT) design to delineate the extent to which intergenerational associations were consistent with a causal influence or due to genetic confounds.

RESULTS

In between-family analyses, parental depression was associated significantly with offspring depression [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.20-1.93] and conduct disorder (CD; HR 2.27, CI 1.31-3.93). Survival analysis indicated that the intergenerational transmission of depression is consistent with a causal (environmental) inference, with a significant intergenerational association in offspring of discordant monozygotic (MZ) twin pairs (HR 1.39, CI 1.00-1.94). Logistic regression analysis suggested that the parental depression-offspring CD association was due to shared genetic liability in the parents and offspring. No intergenerational association was found when comparing the offspring of discordant MZ twins [odds ratio (OR) 1.41, CI 0.63-3.14], but offspring of discordant dizygotic (DZ) twins differed in their rates of CD (OR 2.53, CI 0.95-6.76). All findings remained after controlling for several measured covariates, including history of depression and CD in the twins' spouses.

CONCLUSIONS

The mechanisms underlying associations between parental depression and offspring psychopathology seem to differ depending on the outcome. The results are consistent with a causal environmental role of parental depression in offspring depression whereas common genetic factors account for the association of parental depression and offspring CD.

Confirming the etiology of adolescent acting-out behaviors: an examination of observer-ratings in a sample of adoptive and biological siblings

BACKGROUND

A recent meta-analysis revealed moderate shared environmental influences (C) on most forms of child and adolescent psychopathology (Burt, 2009), including antisocial behavior. Critically, however, the research analyzed in this meta-analysis relied largely on specific informant-reports (and particularly parent and child reports), each of which is subject to various sources of rater bias. Observer-ratings of children's behaviors avoid many of these biases, and are thus well suited to verify the presence of C. Given this, we sought to buttress the evidence supporting C in two key ways. First, we sought to confirm that C contributes to observer-ratings in a sample of adoptive siblings, as similarity between adoptive siblings constitutes a 'direct' estimate of C. Second, we sought to confirm that these shared environmental influences persist across informants (i.e., the effects are not specific to the rater or the context in question).

METHODS

The current study examined the etiology of observer-ratings of acting-out behaviors, as well as sources of etiological overlap across observer-ratings, adolescent self-report and maternal-report in sample of over 600 biological and adoptive sibling pairs from the Sibling Interaction and Behavior Study (SIBS).

RESULTS

Results revealed moderate and significant shared environmental influences on observer-ratings (31%), as well as on the other informant-reports (20-23%). Moreover, a portion of these effects overlapped across measures (C correlations ranged from .32 to .34).

CONCLUSIONS

Such findings argue against passive gene-environment correlations (rGE) and rater bias as primary explanations for earlier findings of C on antisocial behavior, and in this way, offer a critical extension of prior work indicating that the role of shared environmental influences on child and adolescent antisocial behavior was dismissed too soon.

Deviant peer affiliation and antisocial behavior: interaction with Monoamine Oxidase A (MAOA) genotype

Although genetic and environmental factors are separately implicated in the development of antisocial behavior (ASB), interactive models have emerged relatively recently, particularly those incorporating molecular genetic data. Using a large sample of male Caucasian adolescents and young adults from the National Longitudinal Study of Adolescent Health (Add Health), the association of deviant peer affiliation, the 30-base pair variable number tandem repeat polymorphism in promoter region of the monoamine oxidase-A (MAOA) gene, and their interaction, with antisocial behavior (ASB) was investigated. Weighted analyses accounting for over-sampling and clustering within schools as well as controlling for age and wave suggested that deviant peer affiliation and MAOA genotype were each significantly associated with levels of overt ASB across a 6-year period. Only deviant peer affiliation was significantly related to covert ASB, however. Additionally, there was evidence suggestive of a gene-environment interaction (G × E) where the influence of deviant peer affiliation on overt ASB was significantly stronger among individuals with the high-activity MAOA genotype than the low-activity genotype. MAOA was not significantly associated with deviant peer affiliation, thus strengthening the inference of G × E rather than gene-environment correlation (rGE). Different forms of gene-environment interplay and implications for future research on ASB are discussed.

The genetic and environmental etiology of antisocial behavior from childhood to emerging adulthood

Previous research suggests that both genetic and environmental influences are important for antisocial behavior across the life span, even though the prevalence and incidence of antisocial behavior varies considerably across ages. However, little is known of how genetic and environmental effects influence the development of antisocial behavior. A total of 2,600 male and female twins from the population-based Swedish Twin Registry were included in the present study. Antisocial behavior was measured on four occasions, when twins were 8-9, 13-14, 16-17, and 19-20 years old. Longitudinal analyses of the data were conducted using structural equation modeling. The stability of antisocial behavior over time was explained by a common latent persistent antisocial behavior factor. A common genetic influence accounted for 67% of the total variance in this latent factor, the shared environment explained 26%, and the remaining 7% was due to the non-shared environment. Significant age-specific shared environmental factors were found at ages 13-14 years, suggesting that common experiences (e.g., peers) are important for antisocial behavior at this age. Results from this study show that genetic as well as shared environmental influences are important in antisocial behavior that persists from childhood to emerging adulthood.

Resiliency to victimization: the role of genetic factors

There is a burgeoning line of criminological research examining the genetic underpinnings to a wide array of antisocial phenotypes. From this perspective, genes are typically viewed as risk factors that increase the odds of various maladaptive behaviors. However, genes can also have protective effects that insulate against the deleterious effects of environmental pathogens. The authors use this logic as a springboard to examine whether four different genes protect against victimization in a sample of youths determined to be at risk for being victimized. Analysis of data drawn from the National Longitudinal Study of Adolescent Health (Add Health) revealed that certain genetic polymorphisms protected adolescents from victimization. The authors conclude by discussing the complex ways in which genes and the environment can promote resiliency to victimization.

Gender, genetic risk, and criminal behavior

The threshold hypothesis asserts that the prevalence of offending is lower among females because females have a higher threshold for risk than males. As a result, females who do offend should exhibit greater concentrations of genetic and environmental risk than male offenders. In light of these statements, the current study examines the role of genetic factors in the etiology of female offending using data from the National Longitudinal Study of Adolescent Health. The results reveal that the genetic risk threshold is higher for females than for males. However, contrary to the threshold hypothesis, female offenders exhibit fewer genetic risks than male offenders.

Genetic influences on being processed through the criminal justice system: results from a sample of adoptees

BACKGROUND

Behavioral genetic research has revealed that antisocial phenotypes are under genetic influence. This study examines whether genetic factors also affect the odds of being processed through the criminal justice system.

METHODS

A sample of adoptees (n = 191-257) drawn from the National Longitudinal Study of Adolescent Health was analyzed. They self-reported on whether they had ever been arrested, sentenced to probation, incarcerated, and arrested multiple times. Assessments were also conducted of the criminal status of their biological parents.

RESULTS

Adoptees who have a biological father or a biological mother who have been arrested previously are significantly more likely to be arrested, sentenced to probation, incarcerated, and arrested multiple times when compared with adoptees whose biological parents have not been arrested.

CONCLUSIONS

Adoptees who are genetically predisposed to antisocial phenotypes are at risk for being formally processed through the criminal justice system.

Interactive links between theory of mind, peer victimization, and reactive and proactive aggression

This study investigated the relation between theory of mind and reactive and proactive aggression, respectively, as well as the moderating role of peer victimization in this context. The 574 participants were drawn from a longitudinal study of twins. Theory of mind was assessed before school entry, when participants were 5 years old. Reactive and proactive aggression as well as peer victimization were assessed a year later in kindergarten. Results from multilevel regression analyses revealed that low theory of mind was related to a high level of reactive aggression, but only in children who experienced average to high levels of peer victimization. In contrast, a high theory of mind was related to a high level of proactive aggression. Again, this relation was especially pronounced in children who experienced high levels of peer victimization. These findings challenge the social skills deficit view of aggression and provide support for a multidimensional perspective of aggressive behavior.

Neurocriminology

In the past several decades there has been an explosion of research into the biological correlates to antisocial behavior. This chapter reviews the state of current research on the topic, including a review of the genetics, neuroimaging, neuropsychological, and electrophysiological studies in delinquent and antisocial populations. Special attention is paid to the biopsychosocial model and gene-environment interactions in producing antisocial behavior.

Sex differences amongst dependent heroin users: histories, clinical characteristics and predictors of other substance dependence

INTRODUCTION AND AIMS

To examine differences in the characteristics and histories of male and female dependent heroin users, and in the clinical characteristics associated with multiple substance dependence diagnoses.

DESIGN AND METHODS

1513 heroin dependent participants underwent an interview covering substance use and dependence, psychiatric history, child maltreatment, family background, adult violence and criminal history. Family background, demographic and clinical characteristics were analysed by sex. Ordinal regression was used to test for a relationship between number of substance dependence diagnoses and other clinical variables.

RESULTS

Women were more likely to experience most forms of child maltreatment, to first use heroin with a boyfriend or partner, to experience ongoing adult violence at the hands of a partner, and to have a poorer psychiatric history than men. Males had more prevalent lifetime substance dependence diagnoses and criminal histories and were more likely to meet the criteria for ASPD. Predictors of multiple substance dependence diagnoses for both sexes were mental health variables, antisocial behaviour, childhood sexual abuse, victim of adult violence, younger age at first cannabis use and overdose. As the number of dependence diagnoses increased, clinical and behavioural problems increased. Childhood emotional neglect was related to increasing dependence diagnoses for females but not males, whereas PTSD was a significant predictor for males but not females.

DISCUSSION AND CONCLUSIONS

Mental health problems, other substance dependence, childhood and adult trauma were common in this sample, with sex differences indicating different treatment needs and possible different pathways to heroin dependence for men and women.

Violent crime runs in families: a total population study of 12.5 million individuals

BACKGROUND

Etiological theory and prior research with small or selected samples suggest that interpersonal violence clusters in families. However, the strength and pattern of this aggregation remains mostly unknown.

METHOD

We investigated all convictions for violent crime in Sweden 1973-2004 among more than 12.5 million individuals in the nationwide Multi-Generation Register, and compared rates of violent convictions among relatives of violent individuals with relatives of matched, non-violent controls, using a nested case-control design.

RESULTS

We found strong familial aggregation of interpersonal violence among first-degree relatives [e.g. odds ratio (OR)sibling 4.3, 95% confidence interval (CI) 4.2-4.3], lower for more distant relatives (e.g. OR cousin 1.9, 95% CI 1.9-1.9). Risk patterns across biological and adoptive relations provided evidence for both genetic and environmental influences on the development of violent behavior. Familial risks were stronger among women, in higher socio-economic strata, and for early onset interpersonal violence. There were crime-specific effects (e.g. OR sibling for arson 22.4, 95% CI 12.2-41.2), suggesting both general and subtype-specific familial risk factors for violent behavior.

CONCLUSIONS

The observed familiality should be accounted for in criminological research, applied violence risk assessment, and prevention efforts.

Using trajectory analyses to refine phenotype for genetic association: conduct problems and the serotonin transporter (5HTTLPR)

BACKGROUND

Conduct disorder is a serious, relatively common disorder of childhood and adolescence. Findings from genetic association studies searching for genetic determinants of the liability toward such behaviors have been inconsistent. One possible explanation for differential results is that most studies define phenotype from a single assessment; for many adolescents conduct problems decrease in severity over time, whereas for others such behaviors persist. Therefore, longitudinal datasets offer the opportunity to refine phenotype.

METHODS

We used Caucasians that were first assessed during adolescence from the National Youth Survey Family Study. Nine waves of data were used to create latent growth trajectories and test for associations between trajectory class and 5HTTLPR genotype.

RESULTS

For the full sample, 5HTTLPR was not associated with conduct problem phenotypes. However, the short (s) allele was associated with chronic conduct problems in females; a nominally significant sex by 5HTTLPR genotype interaction was noted.

CONCLUSION

Longitudinal studies provide unique opportunities for phenotypic refinement and such techniques, with large samples, may be useful for phenotypic definition with other study designs, such as whole genome association studies.

Adolescent sexual activity and the development of delinquent behavior: the role of relationship context

Despite the well-established association between adolescent sexual activity and delinquent behavior, little research has examined the potential importance of relationship contexts in moderating this association. The current study used longitudinal, behavioral genetic data on 519 same-sex twin pairs (48.6% female) divided into two age cohorts (13-15 and 16-18 years olds) drawn from the National Longitudinal Study of Adolescent Health. Analyses tested whether adolescent sexual activity that occurred in romantic versus non-romantic relationships was associated with delinquency from adolescence to early adulthood, after controlling for genetic influences. Results indicated that, for both younger and older adolescents, common underlying genes influence both sexual behavior and delinquency. After controlling for these genetic influences, there was no within-twin pair association between sexual activity and delinquency in younger adolescents. In older adolescents, sexual activity that occurred in romantic relationships predicted lower levels of delinquency, both cross-sectionally and longitudinally, whereas sexual activity in non-romantic relationships predicted higher levels of delinquency. These results are consistent with emerging research that suggests that the psychological correlates of adolescent sexual activity may be moderated by the social context in which this activity occurs.