The interaction of psychosocial adversity and biological risk in childhood aggression

Serotonin and aggressive behaviour in children and adolescents: a systematic review

OBJECTIVE

The role of serotonin (5-HT) in human aggression has been the subject of a large number of studies, mostly with adults. Meta-analyses indicate a small but significant inverse relationship between central nervous 5-HT availability and aggression, but genetically informed studies suggest two pathways: one to reactive aggression and the other to proactive aggression.

METHOD

We conducted a systemic review on central nervous 5-HT function in children and adolescents, with attention to the function of aggression.

RESULTS

In total, 675 articles were screened for relevance, with 45 reviewed. These included blood assays (e.g. plasma, 5-HIAA; platelet 5-HTR_2A ), epigenetic studies, retrospective PET studies and 5-HT challenge paradigms (e.g. tryptophan depletion). Overall, findings were mixed, with support both for negative and for positive associations of central nervous 5-HT function with aggression in children and adolescents.

CONCLUSION

We propose factors that may be blurring the picture, including problems in the conceptualization and measurement of aggression in young people, the lack of prospective designs and the bias towards clinical samples of boys. Research needs to account for variance in the both motivation for and implementation of aggression, and look to the behavioural economics literature to consider the roles of reward, vengeance and self-control more clearly.

Comparative Evaluation of Child Behavior Checklist-Derived Scales in Children Clinically Referred for Emotional and Behavioral Dysregulation

BACKGROUND

We recently developed the Child Behavior Checklist-Mania Scale (CBCL-MS), a novel and short instrument for the assessment of mania-like symptoms in children and adolescents derived from the CBCL item pool and have demonstrated its construct validity and temporal stability in a longitudinal general population sample.

OBJECTIVE

The aim of this study was to evaluate the construct validity of the 19-item CBCL-MS in a clinical sample and to compare its discriminatory ability to that of the 40-item CBCL-dysregulation profile (CBCL-DP) and the 34-item CBCL-Externalizing Scale.

METHODS

The study sample comprised 202 children, aged 7-12 years, diagnosed with DSM-defined attention deficit hyperactivity disorder (ADHD), conduct disorder (CD), oppositional defiant disorder (ODD), and mood and anxiety disorders based on the Diagnostic Interview Schedule for Children. The construct validity of the CBCL-MS was tested by means of a confirmatory factor analysis. Receiver operating characteristics (ROC) curves and logistic regression analyses adjusted for sex and age were used to assess the discriminatory ability relative to that of the CBCL-DP and the CBCL-Externalizing Scale.

RESULTS

The CBCL-MS had excellent construct validity (comparative fit index = 0.97; Tucker-Lewis index = 0.96; root mean square error of approximation = 0.04). Despite similar overall performance across scales, the clinical range scores of the CBCL-DP and the CBCL-Externalizing Scale were associated with higher odds for ODD and CD, while the clinical range scores of the CBCL-MS were associated with higher odds for mood disorders. The concordance rate among the children who scored within the clinical range of each scale was over 90%.

CONCLUSION

CBCL-MS has good construct validity in general population and clinical samples and is therefore suitable for both clinical practice and research.

Serotonin and impulsive aggression

Aggression is a behavior with evolutionary origins, but is often both destructive and maladaptive in today's society. Research over the past several decades has confirmed the involvement of neurotransmitter function in aggressive behavior. This research has centered around the "serotonin hypothesis." As this literature continues to grow, guided by pre-clinical research and aided by the application of increasingly sophisticated neuroimaging methodology, a more complex picture has emerged. As current pharmacological and therapeutic interventions are effective but imperfect, it is hoped that new insights into the neurobiology of aggression will reveal novel avenues for treatment of this destructive and costly behavior.

Trait-aggressiveness and impulsivity: role of psychological resilience and childhood trauma in a sample of male prisoners

BACKGROUND

One of the major challenges for research in the field of human aggression is the need to define the role of personality and trait-like dimensions, such as impulsivity and aggressiveness, in predisposing to violent behavior.

AIMS

1) To determine whether trait- aggressiveness and impulsivity may be associated with socio-demographic, clinical and crime history variables in a sample of male prisoners; 2) to detect any association of those traits with measures of early traumatic experiences and current resilience traits.

METHODS

A sample of male prisoners (n = 1356) underwent the Brown-Goodwin Assessment for Lifetime History of Aggression (BGLHA) and the Barratt Impulsivity Scale (BIS). Axis I psychiatric disorders were also assessed. Early traumatic experiences and psychological resilience were detected respectively by the Childhood Trauma Questionnaire (CTQ) and the Connor-Davidson Resilience Scale (CD-RISC). Two non-linear logistic regression models were performed to test for the best predictors of trait-aggressiveness and impulsivity.

RESULTS

Subjects with a history of substance use disorders and self-mutilation reported both higher BGLHA and BIS scores. Axis I disorders and suicide attempts were associated with aggressiveness, but not to impulsivity. A consistent correlation was found between BGLHA scores and early traumatic experiences. Resilience was positively correlated to impulsivity but not to aggressiveness scores.

CONCLUSIONS

Our results support the view that aggressiveness and impulsivity are two different, albeit related trait-like dimensions of personality, having a different relationship with resilience, and, inferentially, a different impact over the development of psychiatric disorders.

Revisiting the serotonin-aggression relation in humans: a meta-analysis

The inverse relation between serotonin and human aggression is often portrayed as "reliable," "strong," and "well established" despite decades of conflicting reports and widely recognized methodological limitations. In this systematic review and meta-analysis, we evaluate the evidence for and against the serotonin deficiency hypothesis of human aggression across 4 methods of assessing serotonin: (a) cerebrospinal fluid levels of 5-hydroxyindoleacetic acid (CSF 5-HIAA), (b) acute tryptophan depletion, (c) pharmacological challenge, and (d) endocrine challenge. Results across 175 independent samples and over 6,500 total participants were heterogeneous, but, in aggregate, revealed a small, inverse correlation between serotonin functioning and aggression, anger, and hostility (r = -.12). Pharmacological challenge studies had the largest mean weighted effect size (r = -.21), and CSF 5-HIAA studies had the smallest (r = -.06). Potential methodological and demographic moderators largely failed to account for variability in study outcomes. Notable exceptions included year of publication (effect sizes tended to diminish with time) and self- versus other-reported aggression (other-reported aggression was positively correlated to serotonin functioning). We discuss 4 possible explanations for the pattern of findings: unreliable measures, ambient correlational noise, an unidentified higher order interaction, and a selective serotonergic effect. Finally, we provide 4 recommendations for bringing much needed clarity to this important area of research: acknowledge contradictory findings and avoid selective reporting practices; focus on improving the reliability and validity of serotonin and aggression measures; test for interactions involving personality and/or environmental moderators; and revise the serotonin deficiency hypothesis to account for serotonin's functional complexity.

The Assessment and Treatment of Long-Standing Disruptive Behavior Problems in a 10-Year-Old Boy

A 10-year-old boy was referred for ongoing behavioral problems. These problems were reported as having occurred at home since preschool years and had become increasingly problematic outside of the home in latter years, resulting in frequent suspensions from school. A range of diagnoses had been made in the years prior to referral, including attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), conduct disorder, and pervasive developmental disorder–not otherwise specified (PDD-NOS). The central intervention since age 6 had been pharmacotherapy, with intermittent support at school in the form of school counseling and teachers’ aids. However, the situation appeared to only be worsening, and the need for a more integrated, multimodal approach was recognized. In addition to individual therapy for the client and his mother, the intervention also included engagement of the father, collaboration with other educational and professional service providers, and the development of an integrated plan with shared objectives and strategies. The case explores limitations inherent in taking a medical model diagnostic approach to child behavioral problems and highlights the need to utilize an idiographic approach taking a range of individual psychosocial circumstances into account, rather than taking a more nomothetic treatment approach based mainly on diagnostic assessment.

A prospective study of lipids and serotonin as risk markers of violence and self-harm in acute psychiatric patients

Cross-sectional studies have reported an association between lipids and serotonin levels and aggression, but a literature search revealed a paucity of prospective studies. Subjects of the present naturalistic study were 254 of all (489) involuntary and voluntary acutely admitted patients to a psychiatric hospital during 1year. Serum lipids and platelet serotonin at admission were prospectively compared with recorded intra-institutional and 1-year post-discharge violence and self-harm. Total cholesterol had a significant negative relationship to inpatient suicidal behaviour and inpatient violent behaviour and to 3-month post-discharge violent behaviour. Triglycerides were a significant marker of inpatient self-mutilation and of self-mutilation in combination with suicidal behaviour at 3 and 12 months of follow-up. High-density lipoprotein (HDL) had a significant negative relationship to violence at 12-months, and to repeated violence in seven patients with two or more admissions. The post-discharge relationships between total cholesterol and violence and between triglycerides and self-harm remained significant even when controlling for other possible explanatory variables in a multivariate model. Results did not change after controlling for current medication at admission. There was no association between platelet serotonin and violence or self-harm. Future research may examine if lipid measurements add incremental validity to established clinical risk assessment procedures of violent and self-harm behaviour.

Psychosocial factors associated with parent and teacher reports of aggression in children and adolescents with attention deficit hyperactivity disorder

OBJECTIVE

The prognosis for individuals diagnosed with attention deficit hyperactivity disorder (ADHD) and comorbid aggression is substantially worse than for those with ADHD alone. This study investigates the contribution of key psychosocial factors to both parent and teacher reports of aggressive behaviour in children and adolescents diagnosed with ADHD. It was hypothesized that greater impairment in each would be associated with higher levels of both parent-rated and teacher-rated aggression.

METHOD

Information collected during semi-structured clinical interviews from 676 boys and girls aged 6 to 16 and diagnosed with ADHD was analysed. Measures of potential psychosocial factors including parental psychopathology, family functioning, marital relationship quality and child interpersonal relationship status were administered. Ratings of aggression were obtained from both parents and teachers, and the association of psychosocial measures for each were separately analysed.

RESULTS

Correlation and multiple regression analyses revealed significant associations between parent-rated aggression and measures of increased parent psychopathology, decreased family function and deficient child interpersonal relationships. Teacher-rated aggression was only associated with deficient child interpersonal relationships.

CONCLUSION

The findings highlight important differences in the psychosocial factors that contribute to parent and teacher ratings of aggression in the context of ADHD. The implications of these findings for both the clinician and researcher 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.