Neuropsychological characteristics of adolescents with conduct disorder: association with attention-deficit-hyperactivity and aggression

Default mode network activity and neuropsychological profile in male children and adolescents with attention deficit hyperactivity disorder and conduct disorder

It is known that patients with Attention Deficit and Hyperactivity disorder (ADHD) and Conduct disorder (CD) commonly shows greater symptom severity than those with ADHD alone and worse outcomes. This study researches whether Default mode network (DMN) is altered in adolescents with ADHD + CD, relative to ADHD alone and controls or not. Ten medication-naïve boys with ADHD + CD, ten medication-naïve boys with ADHD and 10-age-matched typically developing (TD) controls underwent functional magnetic resonance imaging (fMRI) scans in the resting state and neuropsychological tasks such as the Wisconsin Card Sorting Test (WCST), Stroop Test TBAG Form (STP), Auditory Verbal learning Test (AVLT), Visual Auditory Digit Span B (VADS B) were applied to all the subjects included. fMRI scans can be used only nine patients in each groups. The findings revealed group differences between cingulate cortex and primary mortor cortex; cingulate cortex and somatosensory association cortex; angular gyrus (AG) and dorsal posterior cingulate cortex, in these networks increased activity was observed in participants with ADHD + CD compared with the ADHD. We found that lower resting state (rs)-activity was observed between left AG and dorsal posterior cingulate cortex, whereas higher rs-activity connectivity were detected between right AG and somatosensory association cortex in ADHD relative to the ones with ADHD + CD. In neuropsyhcological tasks, ADHD + CD group showed poor performance in WISC-R, WCST, Stroop, AVLT tasks compared to TDs. The ADHD + CD group displayed rs-functional abnormalities in DMN. Our results suggest that abnormalities in the intrinsic activity of resting state networks may contribute to the etiology of CD and poor prognosis of ADHD + CD.

Are childhood externalizing disorders the harbinger of early-onset alcohol dependence?

BACKGROUND & OBJECTIVES

The subtyping of alcohol dependence (AD) into early-onset (EO) and late-onset (LO) subgroups has been shown to have clinical and biological validity. As externalizing disorders (EDs) predate AD, the link of ED with age of onset of alcohol dependence needs to be investigated. The aim of this study was to examine the relationship of EDs such as disruptive behaviour disorder (DBD) and attention deficit hyperactivity disorder (ADHD) with age at onset of AD in a sample of male subjects.

METHODS

One hundred consecutive male subjects with AD presenting to the De-Addiction Services and an equal number of biologically unrelated non-substance-dependent control subjects were included in the study. The AD subjects were divided into EO (age of onset of AD ≤25 yr; n = 21) and LO (age of onset of AD >25 yr; n = 79). Subjects were examined for evidence of DBD and ADHD in childhood, and current ADHD using structured instruments such as Semi-Structured Assessment for the Genetic of Alcoholism-IV (SSAGA-IV) and Kiddie - SADS - Present and Lifetime Version (K-SADS-PL). The odds ratio of association of EDs with EO and LO AD was calculated by comparing these subgroups with the biologically unrelated control group. Later, both the subgroups of alcohol dependence were compared for the presence of EDs.

RESULTS

All EDs (DBDs/childhood or adult ADHD) were more common in AD individuals as compared to the controls. However, when AD subgroups were compared with controls, the association of DBDs and ADHD reached a significant level only in the EO subgroup. A comparison of EO and LO AD showed that more EO individuals had history of both childhood disruptive disorder and ADHD compared to LO subgroup. Adult ADHD was also over-represented in EO subgroup.

INTERPRETATION & CONCLUSIONS

Our study showed more EDs in alcohol dependent individuals compared to controls. Further, the association observed between EDs and EO alcohol dependence points towards a developmental continuum between these two conditions.

A longitudinal examination of the developmental executive function hierarchy in children with externalizing behavior problems

OBJECTIVE

Using a 4-year longitudinal design, we evaluated two hypotheses based on developmental executive function (EF) hierarchy accounts in a sample of children with externalizing problems.

METHOD

The participants performed EF tasks when they were between 8 and 12 years (M = 9.93), and again approximately 4 years later when they were between 12 and 15 years (M = 13.36).

RESULTS

Inhibition in middle childhood predicted working memory (WM) 4 years later. Further, deficits in inhibition and sustained attention were more prominent in middle rather than late childhood, whereas poor WM was salient throughout these periods.

CONCLUSIONS

These findings support the hypotheses that EFs develop hierarchically and that EF deficits in ADHD are more prominent in actively developing EFs. They also emphasize ADHD as a developmental disorder.

Neural mechanisms underlying cognitive control of men with lifelong antisocial behavior

Results of meta-analyses suggested subtle deficits in cognitive control among antisocial individuals. Because almost all studies focused on children with conduct problems or adult psychopaths, however, little is known about cognitive control mechanisms among the majority of persistent violent offenders who present an antisocial personality disorder (ASPD). The present study aimed to determine whether offenders with ASPD, relative to non-offenders, display dysfunction in the neural mechanisms underlying cognitive control and to assess the extent to which these dysfunctions are associated with psychopathic traits and trait impulsivity. Participants comprised 21 violent offenders and 23 non-offenders who underwent event-related functional magnetic resonance imaging while performing a non-verbal Stroop task. The offenders, relative to the non-offenders, exhibited reduced response time interference and a different pattern of conflict- and error-related activity in brain areas involved in cognitive control, attention, language, and emotion processing, that is, the anterior cingulate, dorsolateral prefrontal, superior temporal and postcentral cortices, putamen, thalamus, and amygdala. Moreover, between-group differences in behavioural and neural responses revealed associations with core features of psychopathy and attentional impulsivity. Thus, the results of the present study confirmed the hypothesis that offenders with ASPD display alterations in the neural mechanisms underlying cognitive control and that those alterations relate, at least in part, to personality characteristics.

Phonemic verbal fluency is associated with pediatric anxiety disorders: evidence from a community study

BACKGROUND

Anxiety disorders typically begin in childhood and adolescence and predict risk for many problems throughout life. Although some neuropsychological correlates have been described, more research is needed, particularly in adolescents. This study compares neurocognitive characteristics of anxious adolescents with and without comorbidity to externalizing disorders to those of typically developing comparison (TDC) adolescents and adolescents with externalizing disorders alone.

METHODS

The study included 57 adolescents 12-18 years of age (TDC, n=23; anxiety, n=16; externalizing, n=11; comorbid, n=7). We used a neuropsychological battery to assess eight domains: Orientation, attention, visual perception, memory, arithmetic, language, praxis, and executive function.

RESULTS

Multivariate analysis of variance revealed a main effect of group in the neurocognitive domains evaluated (F8,48=2.32, p=0.034, ηp(2)=0.279). Post-hoc analysis revealed that executive functions score differed among groups, specifically in the task of verbal fluency (F[df=3]=5.01, p=0.004, ηp(2)=0.221), with both the anxious groups (anxiety and comorbid) presenting a lower score than the TDC and externalizing groups. This effect was independent of age, intelligence, and levels of education.

CONCLUSIONS

Verbal fluency is specifically impaired in adolescents with anxiety disorders. This extends results from neuroimaging research implicating prefrontal areas in pediatric anxiety disorder neurobiology, and has potential implications to new therapeutics.

Physical aggression, diagnostic presentation, and executive functioning in inpatient adolescents diagnosed with mood disorders

While a relationship has been identified between physical aggression and executive functioning within the adult population, this relationship has not yet been consistently examined in the adolescent population. This study examined the association between physical aggression towards others, self-reported depressive symptoms, and executive functioning within an adolescent inpatient sample diagnosed with a mood disorder. This study consisted of a retrospective chart review of 105 adolescent inpatients (ages 13-19) that received a diagnosis of a mood disorder (excluding Bipolar Disorder). Participants were grouped based on history of aggression towards others, resulting in a mood disorder with physically aggressive symptoms group (n = 49) and a mood disorder without physically aggressive symptoms group (n = 56). Ten scores on various measures of executive functioning were grouped into five executive functioning subdomains: Problem Solving/Planning, Cognitive Flexibility/Set Shifting, Response Inhibition/Interference Control, Fluency, and Working Memory/Simple Attention. Results from analyses of covariance indicated that there were no significant differences (p < .01) between aggression groups on any executive functioning subdomains. Correlation analyses (p < .01) indicated a negative correlation between disruptive behavior disorders and response inhibition/interference control, while anxiety disorders were negatively correlated with problem solving/planning. These findings provide important information regarding the presence of executive dysfunction in adolescent psychiatric conditions, and the specific executive subdomains that are implicated.

Unique relations of age and delinquency with cognitive control

Context processing has significant empirical support as an explanation of age- and psychopathology-related deficiencies in cognitive control. We examined whether context processing generalizes to younger individuals who are in trouble with the law. We tested whether age and delinquency might have unique relations to context processing skills in four samples of male participants: adolescent offenders (n = 43), control adolescents (n = 33), young adult offenders (n = 40), and control young adults (n = 31). We used a modified Stroop task to measure context processing (i.e., attention, memory, and response inhibition). Task performance was superior for older participants in conditions most demanding of context processing skills. Adolescent offenders and control adolescents showed difficulties engaging selective attention to filter out irrelevant information, even after controlling for the effects of age. Control adolescents made the most errors in the condition most demanding of context processing, whereas the other three samples showed slower processing but fewer errors in context processing.

Language Disabilities, Comorbid Developmental Disorders and Risk for Drug Abuse in Adolescence

This paper deals with research which makes links between developmental problems such as language-learning disorders, attentional disorders, and behaviour disturbance on the one hand, and risk for misuse of alcohol and other drugs (AOD) in adolescence on the other. Poor academic performance is frequently cited as a risk for adolescent AOD misuse, however few workers have critically examined the role of linguistically-based academic sub-skills (e.g., oral and written language competence; strong social skills) which normally contribute to academic success, and hence operate as protective factors with respect to risk for AOD misuse. Studies which specifically address language skills and their association with risk for AOD misuse are reviewed, as are investigations which deal with patterns of comorbidity which are typically evident in clinical populations. Particular emphasis is placed on comorbidities between language-learning difficulties on the one hand, and behavioural or attentional disorders, on the other. It is argued that more explicitly investigating and intervening at the level of core language/social skill competencies might serve to strengthen protective factors in vulnerable groups. It is also noted that comorbid problems need to be considered as important covariates in studies of language disordered children and adolescents, rather than being treated as exclusionary criteria.

Gene-environment interplay in the association between pubertal timing and delinquency in adolescent girls

Early pubertal timing places girls at elevated risk for a breadth of negative outcomes, including involvement in delinquent behavior. While previous developmental research has emphasized the unique social challenges faced by early maturing girls, this relation is complicated by genetic influences for both delinquent behavior and pubertal timing, which are seldom controlled for in existing research. The current study uses genetically informed data on 924 female-female twin and sibling pairs drawn from the National Longitudinal Study of Adolescent Health to (1) disentangle biological versus environmental mechanisms for the effects of early pubertal timing and (2) test for gene-environment interactions. Results indicate that early pubertal timing influences girls' delinquency through a complex interplay between biological risk and environmental experiences. Genes related to earlier age at menarche and higher perceived development significantly predict increased involvement in both nonviolent and violent delinquency. Moreover, after accounting for this genetic association between pubertal timing and delinquency, the impact of nonshared environmental influences on delinquency are significantly moderated by pubertal timing, such that the nonshared environment is most important among early maturing girls. This interaction effect is particularly evident for nonviolent delinquency. Overall, results suggest early maturing girls are vulnerable to an interaction between genetic and environmental risks for delinquent behavior.

Investigation of cool and hot executive function in ODD/CD independently of ADHD

BACKGROUND

Children with oppositional defiant disorder/conduct disorder (ODD/CD) have shown deficits in 'cool' abstract-cognitive, and 'hot' reward-related executive function (EF) tasks. However, it is currently unclear to what extent ODD/CD is associated with neuropsychological deficits, independently of attention deficit hyperactivity disorder (ADHD).

METHODS

Fifty-nine adolescents with a history of early-onset oppositional problems, 28 with pure ODD/CD symptoms and 31 with ADHD with or without ODD/CD, and 34 healthy controls were administered a task battery measuring motor response inhibition, sustained attention, cognitive flexibility and reward-related decision-making. Findings were analysed using dimensional and group analyses.

RESULTS

In group analyses both groups with and without ADHD were impaired in EF measures. Dimensional analyses, however, showed that ODD/CD but not ADHD was related to hot EF based on increased risky decision-making in the Iowa Gambling Task. ODD/CD was also independently related to aspects of cool EF independently of ADHD, namely slower speeds of inhibitory responding and increased intra-subject variability.

CONCLUSIONS

These findings show EF deficits associated with ODD/CD independently of ADHD, and implicate reward-related abnormalities in theories of antisocial behaviour development.

Neurocognitive development and externalizing problems: the role of inhibitory control deficits from 4 to 6 years

Executive processes have been posited as important regulators of externalizing problems (EP), but there has been little research on the relation between executive dysfunction and EP in early childhood. During the preschool period, maturation of the prefrontostriatal circuitry parallels increases in inhibitory control (IC). Poor IC development could result in elevated levels of aggressive, disruptive, and impulsive behavior. In this investigation, the development of the relation between IC and EP was examined in preschool and early elementary school children using the Day/Night and Tapping tasks. Children with more EP made more incorrect responses on both IC tasks, consistently across age and sex. The associations between EP and response latencies differed across children, however, with longer latencies on the Tapping task being most characteristic for boys with high levels of EP. This association was not apparent for girls. Two prominent aspects of early EP, aggressive and inattentive behavior, showed only weak unique associations with IC performance. These findings imply that diminished IC accompanies elevated EP as early as the preschool years, and that this decrement persists into the elementary school-age years for both girls and boys, and that accuracy and response latency may confer different information about the development of IC.

Aggressive behavior, bullying, snoring, and sleepiness in schoolchildren

BACKGROUND

To assess whether urban schoolchildren with aggressive behavior are more likely than peers to have symptoms suggestive of sleep-disordered breathing.

METHODS

Cross-sectional survey of sleep and behavior in schoolchildren. Validated screening assessments for conduct problems (Connor's rating scale), bullying behavior, and sleep-disordered breathing (pediatric sleep questionnaire) were completed by parents. Teachers completed Connor's teacher rating scale.

RESULTS

Among 341 subjects (51% female), 110 (32%) were rated by a parent or teacher as having a conduct problem (T-score ⩾65) and 78 (23%) had symptoms suggestive of sleep-disordered breathing. Children with conduct problems, bullying, or discipline referrals, in comparison to non-aggressive peers, more often had symptoms suggestive of sleep-disordered breathing (each p<0.05). Children with vs. without conduct problems were more likely to snore habitually (p<0.5). However, a sleepiness subscale alone, and not a snoring subscale, predicted conduct problems after accounting for age, gender, a measure of socioeconomic status, and stimulant use.

CONCLUSIONS

Urban schoolchildren with aggressive behaviors may have symptoms of sleep-disordered breathing with disproportionate frequency. Sleepiness may impair emotional regulation necessary to control aggression.

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.

The Role of Attention-Deficit/hyperactivity Disorder in the Association between Verbal Ability and Conduct Disorder

Although there is clear evidence that low verbal ability is a risk factor for conduct disorder (CD), some researchers have questioned whether this association is due to the common comorbidity between attention-deficit/hyperactivity disorder (ADHD) and CD. The present study examined the association among verbal ability, ADHD, and CD in a genetically informative sample in order to examine the role of genes and/or environmental influences shared in common with ADHD on the covariation between verbal ability and CD. Participants were 2744 adolescents from the Center for Antisocial Drug Dependence (CADD), and included 360 monozygotic (MZ) female twin pairs, 221 dizygotic (DZ) female twin pairs, 297 MZ male twin pairs, 220 DZ male twin pairs, and 274 opposite-sex DZ twin pairs. The Diagnostic Interview Schedule for Children (DISC-IV) was used to assess lifetime symptoms of ADHD and CD. Verbal ability was assessed via the Vocabulary subtest of the Wechsler Adult Intelligence Scale III (WAIS-III) for individuals over the age of 16 and the Vocabulary subtest of the Wechsler Intelligence Scale for Children III (WISC-III) for individuals under the age of 16. There was a small but significant negative covariance between verbal ability and CD and between verbal ability and ADHD. Results also suggest that the covariation between verbal ability and CD is due to influences shared in common with ADHD.

Neuropsychologische Korrelate aggressiv-dissozialen Verhaltens

Bei der Erforschung aggressiv-dissozialen Verhaltens wurde die Bedeutung von neuropsychologischen Funktionen bisher vergleichsweise selten berücksichtigt – zudem sind die Ergebnisse heterogen. Mit einer umfangreichen Literatursuche wurden Studien identifiziert, die die Zusammenhänge von neuropsychologischen Leistungen und aggressiv-dissozialem Verhalten bei Jugendlichen untersuchten. Die Befunde werden differenziert nach Subtypen aggressiv-dissozialen Verhaltens dargestellt (Störung des Sozialverhaltens, physisch-aggressives Verhalten, straffälliges Verhalten und Psychopathie). Insgesamt weisen sie auf die Bedeutung der sprachlichen und exekutiven Funktionen hin. Defizite in diesen Funktionsbereichen sind insbesondere bei früh auftretendem stabilen und gewalttätigen Verhalten nachweisbar. Sprache, exekutive Funktionen und ihr Zusammenspiel werden in ihrer Bedeutung für sozial-kompetentes und aggressiv-dissoziales Verhalten diskutiert und die Ergebnisse werden vor dem Hintergrund der verwendeten Methodik, Einfluss von ADHS und Intelligenz kritisch besprochen. Abschließend werden neuropsychologische Defizite und biosoziale Risikofaktoren in der Entwicklung aggressiv-dissozialen Verhaltens miteinander in Beziehung gesetzt und Schlussfolgerungen für die klinische Praxis dargestellt.

The neurocognition of conduct disorder behaviors: specificity to physical aggression and theft after controlling for ADHD symptoms

There is growing evidence that among the different conduct disorder (CD) behaviors, physical aggression, but not theft, links to low neurocognitive abilities. Specifically, physical aggression has consistently been found to be negatively related to neurocognitive abilities, whereas theft has been shown to be either positively or not related to neurocognition. The specificity of these links needs further examination because attention deficit hyperactivity disorder (ADHD) links to both physical aggression and neurocognitive variation. The development of self-reported physical aggression and theft, from age 11 to 17 years, was studied in a prospective at-risk male cohort via a dual process latent growth curve model. Seven neurocognitive tests at age 20 were regressed on the growth parameters of physical aggression and theft. The links between neurocognition and the growth parameters of physical aggression and theft were adjusted for ADHD symptoms at ages 11 and 15 (parent, child and teacher reports). Results indicated that verbal abilities were negatively related to physical aggression while they were positively associated with theft. However, inductive reasoning was negatively associated with increases in theft across adolescence. Symptoms of ADHD accounted for part of the neurocognitive test links with physical aggression but did not account for the associations with theft. These differences emphasize the importance of examining specific CD behaviors to better understand their neurodevelopmental mechanisms. They also suggest that youth who engage in different levels of physical aggression or theft behaviors may require different preventive and corrective interventions.

Association among aggressiveness, neurocognitive function, and the Val66Met polymorphism of brain-derived neurotrophic factor gene in male schizophrenic patients

BACKGROUND

The aim of this study was to investigate the association among aggressive behavior, neuropsychological function, and the Val66Met functional polymorphism of brain-derived neurotrophic factor (BDNF) gene in male schizophrenic patients.

METHODS

We examined 51 male patients with schizophrenia who had committed homicide (ie, H-SCZ), 50 male patients with schizophrenia who had not committed homicide (ie, NH-SCZ), and 50 healthy male controls. Patients were evaluated using the Positive and Negative Syndrome Scale, Life History of Aggression, and the Overt Aggression Scale. In addition, patients were given neurocognitive function tests, including Korean-Wechsler Adult Intelligence Scale short form, the Korean version of the Rey Memory Test, the Stroop Test, and the Wisconsin Card Sorting Test. The Val66Met polymorphism of the BDNF gene was also genotyped in all schizophrenic patients.

RESULTS

We observed no significant difference between patients in the H-SCZ and NH-SCZ groups, with regard to Positive and Negative Syndrome Scale scores. Total Life History of Aggression (P < .01) and Overt Aggression Scale scores for the most severe episode (P < .01) or for the previous month (P < .05) were higher in the H-SCZ group than in the NH-SCZ group. There were no significant differences in the genotype distribution or allelic frequency of the Val66Met polymorphism between the schizophrenic groups. In addition, we observed no significant differences between H-SCZ and NH-SCZ groups with regard to performance on neuropsychological tests. The Met allele of the Val66Met polymorphism was associated with poor intelligence quotient, memory quotient), learning, and delayed recall in the H-SCZ group. However, genotype did not seem to influence neurocognitive function in schizophrenic patients who had committed homicide.

CONCLUSIONS

The neurocognitive tests used in our study were unable to distinguish between violent and nonviolent schizophrenic patients. Furthermore, the Val66Met polymorphism was not associated with aggressiveness in patients with schizophrenia.

Different neurocognitive functions regulating physical aggression and hyperactivity in early childhood

BACKGROUND

There are strong parallels between early childhood and adolescent behavior problems. However, we do not know if behavioral symptoms associate with neurocognitive processes in very young children as they do in older children.

METHODS

We studied a population-based birth cohort of children (N = 1,950) whose developmental trajectories of physical aggression and hyperactivity were assessed between the ages of 17 and 41 months. We measured the following neurocognitive abilities at 41 months of age: Receptive vocabulary, visuospatial organization, and short-term memory.

RESULTS

After controlling for other neurocognitive abilities, frequent physical aggression was related specifically to receptive vocabulary deficits (p < .0001) while frequent hyperactivity was related specifically to deficits of visuospatial organization (p < .0001). The pattern of associations was robust despite controls for socioeconomic and perinatal status.

CONCLUSIONS

The different neurocognitive correlates of physical aggression and hyperactivity problems observed during adolescence are apparent in early childhood. Whereas physical aggression problems are associated with language deficits, hyperactivity problems are related to non-verbal deficits.

Reactive and proactive control in incarcerated and community adolescents and young adults

This study compared the cognitive control skills of male incarcerated adolescents (n=44), male control adolescents (n=33), male incarcerated young adults (n=41), and male control young adults (n=35) using the AX-Continuous Performance Task. This task measures proactive control (the ability to maintain a mental representation of goal-related information in preparation for a behavioral response) and reactive control (the ability to activate goal-related information in response to an external trigger). Incarcerated individuals had more difficulty implementing proactive control, whereas control individuals had more difficulty implementing reactive control. Adolescents had more difficulty with both reactive and proactive control compared to young adults, suggesting that both skills improve with age. Additional analyses indicated that the effect of age on proactive control was due to the presence of attention-deficit/hyperactivity disorder, whereas the effect of age on reactive control appeared to be a natural developmental trend that could not be explained by other variables. These findings are considered in relation to the dual mechanisms of control theory (Braver, Gray, & Burgess, 2007).

Executive functions in preschool children with aggressive behavior: impairments in inhibitory control

The question whether executive function (EF) deficits in children are associated with conduct problems remains controversial. Although the origins of aggressive behavior are to be found in early childhood, findings from EF studies in preschool children with aggressive behavior are inconsistent. The current study aimed to investigate whether preschool children with aggressive behavior show impairments in EF. From a population-based sample, 82 preschool children who were showing aggressive behavior as indicated by scores at or above the 93rd percentile on the Aggressive Behavior Scale of the CBCL 1 1/2-5 were selected. These children with aggressive behavior were matched on IQ to a group of typically developing control children (N = 99). Six neuropsychological tasks were administered to assess set shifting, inhibition, working memory and verbal fluency. A factor analysis was conducted which yielded one clear factor: inhibition. Aggressive preschool children showed poorer performance on this inhibition factor than control children and boys performed worse on this factor than girls. This association between aggressive behavior and inhibition deficits was maintained after controlling for attention problems. In addition, gender differences in all EFs measured were found with boys exhibiting more impairment in EF than girls. These findings demonstrate that preschool children with aggressive behavior show impairments in inhibition, irrespective of attention problems.

Neuropsychological function in adolescent girls with conduct disorder

OBJECTIVES

Conduct disorder (CD) in adolescent girls is a significant problem, but few data exist on the neuropsychological function of girls with this disorder. We investigated whether girls with CD have poorer neuropsychological function than girls without any psychiatric disorder, whether these differences remained significant after adjusting for demographics, and whether psychiatric comorbidity, age at onset of CD symptoms, or aggressive CD behaviors were differentially associated with neuropsychological function within the CD group.

METHOD

Ninety-three girls, ages 15 to 17 years, from the community (52 CD; 41 without any disorder [normal controls]) received a neuropsychological battery examining motor/laterality, general intelligence, language, visuospatial, visual-motor, executive function, and academic achievement domains.

RESULTS

Girls with CD had lower general intelligence and poorer performance on visuospatial, executive function, and academic achievement domains. After adjusting for demographic factors, scores in the CD group were worse for general intelligence and in the visuospatial and academic achievement domains. Comorbid substance use disorder was negatively correlated with motor/laterality; no other intra-CD group comparisons were statistically significant.

CONCLUSIONS

Girls with CD had deficits in several domains of neuropsychological function. Possible explanations for the findings and clinical implications are discussed.

Neurobiology of aggression and violence

Acts of violence account for an estimated 1.43 million deaths worldwide annually. While violence can occur in many contexts, individual acts of aggression account for the majority of instances. In some individuals, repetitive acts of aggression are grounded in an underlying neurobiological susceptibility that is just beginning to be understood. The failure of "top-down" control systems in the prefrontal cortex to modulate aggressive acts that are triggered by anger provoking stimuli appears to play an important role. An imbalance between prefrontal regulatory influences and hyper-responsivity of the amygdala and other limbic regions involved in affective evaluation are implicated. Insufficient serotonergic facilitation of "top-down" control, excessive catecholaminergic stimulation, and subcortical imbalances of glutamatergic/gabaminergic systems as well as pathology in neuropeptide systems involved in the regulation of affiliative behavior may contribute to abnormalities in this circuitry. Thus, pharmacological interventions such as mood stabilizers, which dampen limbic irritability, or selective serotonin reuptake inhibitors (SSRIs), which may enhance "top-down" control, as well as psychosocial interventions to develop alternative coping skills and reinforce reflective delays may be therapeutic.

Conduct Problems in Adolescence: Three Domains of Inhibition and Effect of Gender

Behavioral and neuropsychological evidence has often shown that children with conduct disorder drawn from clinical populations show problems with impulsivity and are impaired in motor tasks of inhibitory control. We explored the relation between conduct problems and inhibitory deficits in a community sample. Three domains of inhibition were explored in 54 adolescents with conduct problems compared to 53 age, IQ, sex, school, and ethnicity matched controls in 2 geographical areas. Motor response inhibition was assessed using the Stop task, verbal inhibition using the Hayling Sentence Completion test, and cognitive interference inhibition using the Stroop task. Adolescents with conduct problems showed deficits in executive and inhibitory processes of the motor response inhibition task, but were unimpaired in cognitive or verbal inhibitory control. No sex differences were observed and impairments were independent of IQ or geographical location. Findings suggest that motor deficits, rather than higher cognitive forms of inhibitory control, are a specific deficit in children with conduct problems, that girls are as affected as boys, and that motor impulsiveness is a dimensional trait associated with conduct problems, as it is also observed in the community.

Prefrontal Cortex, Thalamus, and Cerebellar Volumes in Adolescents and Young Adults with Adolescent-Onset Alcohol Use Disorders and Comorbid Mental Disorders

BACKGROUND

In adults, prefrontal, thalamic, and cerebellar brain injury is associated with excessive ethanol intake. As these brain structures are actively maturing during adolescence, we hypothesized that subjects with adolescent-onset alcohol use disorders, compared with control subjects, would have smaller brain volumes in these areas. Thus, we compared prefrontal-thalamic-cerebellar measures of adolescents and young adults with adolescent-onset alcohol use disorders (AUD, defined as DSM-IV alcohol dependence or abuse) with those of sociodemographically similar control subjects.

METHODS

Magnetic resonance imaging was used to measure prefrontal cortex, thalamic, and cerebellar volumes in 14 subjects (eight males, six females) with an AUD (mean age, 17.0+/-2.1 years) and 28 control subjects (16 males, 12 females; 16.9+/-2.3 years). All AUD subjects were recruited from substance abuse treatment programs and had comorbid mental disorders.

RESULTS

Subjects with alcohol use disorders had smaller prefrontal cortex and prefrontal cortex white matter volumes compared with control subjects. Right, left, and total thalamic, pons/brainstem, right and left cerebellar hemispheric, total cerebellar, and cerebellar vermis volumes did not differ between groups. There was a significant sex-by-group effect, indicating that males with an adolescent-onset AUD compared with control males had smaller cerebellar volumes, whereas the two female groups did not differ in cerebellar volumes. Prefrontal cortex volume variables significantly correlated with measures of alcohol consumption.

CONCLUSIONS

These findings suggest that a smaller prefrontal cortex is associated with early-onset drinking in individuals with comorbid mental disorders. Further studies are warranted to examine if a smaller prefrontal cortex represents a vulnerability to, or a consequence of, early-onset drinking.

Neurocognitive skills moderate urban male adolescents' responses to preventive intervention materials

The present experiment was designed to determine whether individual variation in neurobiological mechanisms associated with substance abuse risk moderated effects of a brief preventive intervention on social competency skills. This study was conducted in collaboration with the ongoing preventive intervention study at Johns Hopkins University Prevention Intervention Research Center (JHU PIRC) within the Baltimore City Public Schools. A subsample (N = 120) of male 9th grade students was recruited from the larger JHU study population. Approximately half of the participants had a current or lifetime diagnosis of CD while the other half had no diagnosis of CD or other reported problem behaviors. Measures of executive cognitive function (ECF), emotional perception and intelligence were administered. In a later session, participants were randomly assigned to either an experimental or control group. The experimental group underwent a facilitated session using excerpted materials from a model preventive intervention, Positive Adolescent Choices Training (PACT), and controls received no intervention. Outcomes (i.e., social competency skills) were assessed using virtual reality vignettes involving behavioral choices as well as three social cognition questionnaires. Poor cognitive and emotional performance and a diagnosis of CD predicted less favorable change in social competency skills in response to the prevention curriculum. This study provides evidence for the moderating effects of neurocognitive and emotional regulatory functions on ability of urban male youth to respond to preventive intervention materials.

Which Executive Functioning Deficits Are Associated With AD/HD, ODD/CD and Comorbid AD/HD+ODD/CD?

This study investigated (1) whether attention deficit/hyperactivity disorder (AD/HD) is associated with executive functioning (EF) deficits while controlling for oppositional defiant disorder/conduct disorder (ODD/CD), (2) whether ODD/CD is associated with EF deficits while controlling for AD/HD, and (3) whether a combination of AD/HD and ODD/CD is associated with EF deficits (and the possibility that there is no association between EF deficits and AD/HD or ODD/CD in isolation). Subjects were 99 children ages 6-12 years. Three putative domains of EF were investigated using well-validated tests: verbal fluency, working memory, and planning. Independent of ODD/CD, AD/HD was associated with deficits in planning and working memory, but not in verbal fluency. Only teacher rated AD/HD, but not parent rated AD/HD, significantly contributed to the prediction of EF task performance. No EF deficits were associated with ODD/CD. The presence of comorbid AD/HD accounts for the EF deficits in children with comorbid AD/HD+ODD/CD. These results suggest that EF deficits are unique to AD/HD and support the model proposed by R. A. Barkley (1997).

Neuropsychological deficits in adolescents with conduct disorder and comorbid bipolar disorder: a pilot study

OBJECTIVE

We report pilot data on neuropsychological deficits in aggressive juvenile offenders with and without bipolar disorder compared with each other and healthy controls.

METHOD

We assessed 52 adolescents and their parent or guardians: 36 incarcerated juvenile offenders and 16 community controls using the Schedule for Affective Disorders and Schizophrenia for School Age Children, Present and Life-Time Version and a neuropsychological testing battery. All incarcerated subjects (n=34) met criteria for Conduct Disorder (CD); 26 are classified as Non-BD-CD, and eight with CD and Bipolar disorder (CD-BD). These subjects were compared to community controls (n=16) matched for age, gender, SES and ethnicity.

RESULTS

Relative to controls, the Non-BD-CD subjects' impairments (p<0.05) were in cognitive ability, set shifting/inhibition, planning and verbal memory-language functioning. The CD-BD group displayed impairments (p<0.05) relative to controls in cognitive ability, set shifting, verbal memory-language functioning, and visuospatial tasks. The Non-BD-CD and CD-BD groups however did not display significant differences on most neuropsychological measures compared with each other. When we controlled for Attention Deficit Hyperactivity Disorder, the Non-CD-BP subjects continued to show deficits on Verbal measures where the CD-BD subjects maintained deficits in measures of cognitive ability, verbal measures and visual spatial tests.

CONCLUSIONS

Juvenile offender with CD displayed a wide range of deficits on neuropsychological testing compared with controls. Although juvenile offenders with and without BD differed on their clinical presentation, differences on neuropsychological measures are not specific and may be related to comorbid diagnoses.

Neuropsychological functioning in children with DSM-IV combined type Attention Deficit Hyperactivity Disorder

OBJECTIVE

To compare the global cognitive functioning and frontal lobe functioning of children with and without DSM-IV combined type Attention Deficit Hyperactivity Disorder (ADHD).

METHOD

Participants were 6 to 10 year old, clinic-referred children diagnosed with combined type ADHD, who were medication naïve; and an age (+/- 3 months) and sex matched group of children without behaviour problems. The performance of the two groups were compared on measures of intellectual functioning and tests designed to assess the functions of the frontal lobes (verbal and-non-verbal fluency, reasoning, problem solving, spatial working memory, attention).

RESULTS

The children with ADHD obtained significantly lower Wechsler Intelligence Scale for Children-third edition IQ scores than controls and performed more poorly across the range of frontal lobe tests. Group differences on these tests were attenuated when IQ scores were included in the analyses as a covariate.

CONCLUSIONS

Children with combined type ADHD have mild to moderate global cognitive impairment together with some impairment of functions subserved by the frontal lobes. Longitudinal studies are required to determine if the deficit in global cognitive functioning is a primary deficit or secondary to the deficit in frontal lobe functioning. The importance of neuro-psychological assessment and follow-up for children with ADHD is stressed. Study limitations relate to the generalizability of the findings and the absence of a psychiatric control group.

How specific is a deficit of executive functioning for attention-deficit/hyperactivity disorder?

A selective review of research in the executive functioning (EF) is given for attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), conduct disorder (CD), higher functioning autism (HFA) and Tourette syndrome. The review is restricted due to changes in the classification of the disorder in recent years and secondly the heterogeneity of EF is restricted to five key areas of concern, inhibition, set shifting, working memory, planning, and fluency. The review makes clear that there are strong differences between child psychopathological groups and controls on these EFs. However, future research will be needed to identify an EF deficit or profile, which is specific for these disorders.