Will future forensic assessment be neurobiologic?

Young people's Perception of Group Climate in Juvenile Justice Centers in an Australian State, a Pilot Study

There is ample evidence to demonstrate that a positive group climate in juvenile justice centers contributes to improvements in motivation for positive behavior and reducing incidents and even recidivism. Being provided opportunities for growth and development and being actively supported by well-trained staff creates a positive atmosphere and minimal repression. Such a pedagogical group climate is strongly related to fulfilling the basic psychological needs of the young people and is promoted by relational security. Following a series of challenging situations inside youth justice centers in Australia, we explored the opportunities for investing in staff training on awareness of basic psychological needs of these young people and introducing the concept of an open, positive group climate. This study reports the results of an explorative measurement of perceived group climate in four units of two juvenile justice centers in Victoria (Australia). The young people (N = 57) were provided with the Prison Group Climate Instrument. The results of the group climate research and a cross-cultural comparison show that there are inherent strengths but also important opportunities for improvement in the group climate experienced by young people. Recommendations to improve the group climate are discussed in this paper.

Neurobiological Responses towards Stimuli Depicting Aggressive Interactions in Delinquent Young Adults and Controls: No Relation to Reactive and Proactive Aggression

Neurobiological measures underlying aggressive behavior have gained attention due to their potential to inform risk assessment and treatment interventions. Aberrations in responsivity of the autonomic nervous system and electrophysiological responses to arousal-inducing stimuli have been related to emotional dysregulation and aggressive behavior. However, studies have often been performed in community samples, using tasks that induce arousal but not specifically depict aggression. In this study, we examined differences in psychophysiological (i.e., heart rate, respiratory sinus arrhythmia, skin conductance level) and electrophysiological responses (i.e., P3, late positive potential, mu suppression) to aggressive versus neutral scenes in a sample of 118 delinquent young adults and 25 controls (all male, aged 18–27). With respect to group differences, we only found significant higher SCL reactivity during the task in the delinquent group compared to controls, but this was irrespective of condition (aggressive and neutral interactions). Within the delinquent group, we also examined associations between the neurobiological measures and reactive and proactive aggression. No significant associations were found. Therefore, although we found some indication of emotional dysregulation in these delinquent young adults, future studies should further elucidate the neurobiological mechanisms underlying emotional dysregulation in relation to different types of aggression.

Integrating Cognitive Developmental Neuroscience in Society: Lessons Learned From a Multidisciplinary Research Project on Education and Social Safety of Youth

Integrating fundamental science in society, with the goal to translate research findings to daily practice, comes with certain challenges. Successfully integrating research projects into society requires (1) good collaboration between scientists and societal stakeholders, (2) collaboration partners with common expectations and goals, and (3) investment in clear communication. Here we describe an integrative research project conducted by a large Dutch consortium that consisted of neuroscientists, psychologists, sociologists, ethicists, teachers, health care professionals and policy makers, focusing on applying cognitive developmental neuroscience for the benefit of youth in education and social safety. We argue that to effectively integrate cognitive developmental neuroscience in society, (1) it is necessary to invest in a well-functioning, diverse and multidisciplinary team involving societal stakeholders and youth themselves from the start of the project. This aids to build a so-called productive interactive network that increases the chances to realize societal impact in the long-term. Additionally, we propose that to integrate knowledge, (2) a different than standard research approach should be taken. When focusing on integration, the ultimate goal of research is not solely to understand the world better, but also to intervene with real-life situations, such as education or (forensic) youth care. To accomplish this goal, we propose an approach in which integration is not only started after the research has been conducted, but taken into account throughout the entire project. This approach helps to create common expectations and goals between different stakeholders. Finally, we argue that (3) dedicating sufficient resources to effective communication, both within the consortium and between scientists and society, greatly benefits the integration of cognitive developmental neuroscience in society.

Using the biopsychosocial model for identifying subgroups of detained juveniles at different risk of re-offending in practice: a latent class regression analysis approach

BACKGROUND

Juvenile delinquents constitute a heterogeneous group, which complicates decision-making based on risk assessment. Various psychosocial factors have been used to define clinically relevant subgroups of juvenile offenders, while neurobiological variables have not yet been integrated in this context. Moreover, translation of neurobiological group differences to individual risk assessment has proven difficult. We aimed to identify clinically relevant subgroups associated with differential youth offending outcomes, based on psychosocial and neurobiological characteristics, and to test whether the resulting model can be used for risk assessment of individual cases.

METHODS

A group of 223 detained juveniles from juvenile justice institutions was studied. Latent class regression analysis was used to detect subgroups associated with differential offending outcome (recidivism at 12 month follow-up). As a proof of principle, it was tested in a separate group of 76 participants whether individual cases could be assigned to the identified subgroups, using a prototype 'tool' for calculating class membership.

RESULTS

Three subgroups were identified: a 'high risk-externalizing' subgroup, a 'medium risk-adverse environment' subgroup, and a 'low risk-psychopathic traits' subgroup. Within these subgroups, both autonomic nervous system and neuroendocrinological measures added differentially to the prediction of subtypes of reoffending (no, non-violent, violent). The 'tool' for calculating class membership correctly assigned 92.1% of participants to a class and reoffending risk.

CONCLUSIONS

The LCRA approach appears to be a useful approach to integrate neurobiological and psychosocial risk factors to identify subgroups with different re-offending risk within juvenile justice institutions. This approach may be useful in the development of a biopsychosocial assessment tool and may eventually help clinicians to assign individuals to those subgroups and subsequently tailor intervention based on their re-offending risk.

Neurocognitive predictors of treatment completion and daytime activities at follow-up in multiproblem young adults

Previous research has shown an association between cognitive control deficits and problematic behavior such as antisocial behavior and substance use, but little is known about the predictive value of cognitive control for treatment outcome. The current study tests whether selected markers of baseline cognitive control predict (1) treatment completion of a day treatment program involving a combination of approaches for multiproblem young adults and (2) daytime activities a year after the start of treatment, over and above psychological, social, and criminal characteristics. We assessed individual, neurobiological, and neurobehavioral measures, including functional brain activity during an inhibition task and two electroencephalographic measures of error processing in 127 male multiproblem young adults (age 18-27 years). We performed two hierarchical regression models to test the predictive power of cognitive control for treatment completion and daytime activities at follow-up. The overall models did not significantly predict treatment completion or daytime activities at follow-up. However, activity in the anterior cingulate cortex (ACC) during response inhibition, years of regular alcohol use, internalizing problems, and ethnicity were all significant individual predictors of daytime activity at follow-up. In conclusion, cognitive control could not predict treatment completion or daytime activities a year after the start of treatment over and above individual characteristics. However, results indicate a direct association between brain activity during response inhibition and participation in daytime activities, such as work or school, after treatment. As adequate baseline inhibitory control is associated with a positive outcome at follow-up, this suggests interventions targeting cognitive control might result in better outcomes at follow-up.

THE IOWA GAMBLING TASK IN VIOLENT AND NONVIOLENT INCARCERATED MALE ADOLESCENTS

Previous studies have found impaired affective decision-making, as measured by the Iowa Gambling Task (IGT), in various antisocial populations. This is the first study to compare the IGT in violent and nonviolent incarcerated American youth. The IGT was administered to 185 incarcerated adolescent male offenders charged with either nonviolent (38.4%) or violent (61.6%) crimes. General linear mixed models and t tests were used to assess differences between the groups. The full sample performed worse than if they had selected from the decks at random. The violent offenders performed more poorly than the nonviolent offenders overall, primarily because they preferred "disadvantageous" Deck B to a greater degree; however, they did demonstrate some degree of learning by the final block of the task. Adolescent offenders demonstrate impaired affective decision-making. Behavior suggested preferential attention to frequency of loss and amount of gain and inattention to amount of loss.

Using biological factors to individualize interventions for youth with conduct problems: Current state and ethical issues

A growing body of evidence suggests that biological factors such as genes, hormone levels, brain structure, and brain functioning influence the development and trajectory of conduct problems in youth. In addition, biological factors affect how individuals respond to the environment, including how individuals respond to programs designed to prevent or treat conduct problems. Programs designed to reduce behavior problems in youth would have the greatest impact if they were targeted toward youth who need it the most (e.g., who are mostly likely to demonstrate persistent behavior problems) as well as youth who may benefit the most from the program. Biological information may improve our ability to make decisions about which type or level of intervention is best for a particular child, thus maximizing overall effectiveness, but it also raises a number of ethical concerns. These include the idea that we may be providing fewer services to some youth based on biological factors, and that information about biological risk could potentially lead to discrimination or labeling. In this article, I discuss the risks and benefits of using biological information to individualize interventions for youth with conduct problems.

Blunted cortisol reactivity and risky driving in young offenders - a pilot study

Adolescent risky driving is a significant burden on public health. Young offenders (i.e. under custody and supervision of the criminal justice system) may be particularly vulnerable, but research is scant. Previous work indicated that blunted cortisol reactivity to stress is a marker of risk-taking predisposition, including risky driving. In this study, we hypothesized that young offenders display higher levels of risky driving than a non-offender comparison group, and that cortisol reactivity contributes to the variance in risky driving independent of other associated characteristics (i.e. impulsivity, risk taking, alcohol and drug use). We found that young offenders (n = 20) showed riskier driving in simulation than comparison group (n = 9), and blunted cortisol reactivity was significantly associated with risky driving. The results suggest young offenders are prone to risky driving, and that individual differences in the cortisol stress response may be an explanatory factor.

The Relation Between Living Group Climate, Aggression, and Callous-Unemotional Traits in Delinquent Boys in Detention

Aggression and callous-unemotional (CU) traits are common problems in incarcerated delinquent youth. The present study was conducted to examine whether living group climate was associated with aggression and CU traits in late adolescent male offenders ( N = 156) in a German youth prison. A structural equation model was fitted to the data and showed associations between repression and reactive aggression and CU traits, but no associations between an open and supportive living group climate and aggression and CU traits. Previous research in Dutch youth prisons did not find a relation between repression and aggression, buta relation between a positive living group climate and less aggression. These different findings may reflect differences in the German and Dutch prison system. Implications for practice are discussed.

Prevalence of psychiatric disorders, comorbidity patterns, and repeat offending among male juvenile detainees in South Korea: a cross-sectional study

BACKGROUND

High rates of psychiatric disorders and comorbidities have been reported in juvenile detainees, and both phenomena are thought to contribute to repeat offending. However, research on this topic has been limited in Asian countries, like South Korea. The purpose of this study was to examine the prevalence of psychiatric disorders, comorbidity patterns, and the relationship between psychiatric disorders and repeat offending among a cross-section of youths detained in a male juvenile detention center in South Korea.

METHODS

One hundred seventy-three juvenile detainees were recruited. The distribution of psychiatric disorders within the sample was estimated by applying criteria from the Diagnostic and Statistical Manual of Mental Disorders IV. Logistic regression was used to assess significant comorbidity patterns and relationships between psychiatric disorders and repeat offending.

RESULTS

In all, 90.8% of the detainees had at least one psychiatric diagnosis, and 75.1% had psychiatric comorbidities. The most common psychiatric disorder was alcohol use disorder, followed by conduct disorder and attention-deficit hyperactivity disorder. Among the comorbidities present, alcohol use disorder with disruptive behavior disorder was the most common combination. The presence of two psychiatric disorders was associated with a higher rate of recidivism, and alcohol use disorder was also associated with repeat offending when combined with disruptive behavior disorders, but not with anxiety disorders, major depression, or psychotic disorders.

CONCLUSIONS

Juvenile detainees evidence high rates of psychiatric disorders and comorbidities. Assessment of and intervention in psychiatric disorders, especially alcohol use disorder and comorbid alcohol use disorder with disruptive behavior disorders, may help prevent further offenses.

Preditores do Comportamento Antissocial em Adolescentes

RESUMO Este estudo investigou preditores do comportamento antissocial em 142 adolescentes em medida socioeducativa de internação (G1) e 691 estudantes de escolas públicas (G2), que responderam a um questionário. Foram observadas diferenças significativas entre os grupos quanto ao comportamento antissocial, violência intra e extrafamiliar, uso de drogas e eventos estressores, com médias mais altas em G1. Dentre as variáveis investigadas, grupo, uso de drogas e eventos estressores, juntamente com a covariável sexo, explicaram 66,5% da variável dependente. Um modelo de path analysis demonstrou que as variáveis sexo e ambiente estressor, computado pelos eventos estressores, qualidade do relacionamento familiar e violência intra e extrafamiliar predizem o uso de drogas e comportamentos antissociais.

[Female conduct disorders]

The last few years have seen much research on girls with conduct disorder (CD). This article summarizes the gender-specific data regarding prevalence, differences with respect to symptomatology (e.g., subtypes of aggression, callous-unemotional (cu)-traits), and it presents data on the autonomic and neuroendocrine stress system as well as genetic, neurocognitive, and neuroimaging data. Differences in the impact of environmental factors on boys and girls for the development of CD are discussed. Taken together, the data indicate that there is great overlap in symptomatology, personality traits, and neurobiological aberrations in girls and boys with CD. Since fewer girls than boys exhibit CD symptomatology, further investigations on CD in girls might help to identify resilience factors that could improve future therapeutic interventions.

Neural correlates of social decision-making in severely antisocial adolescents

Neurobiological and behavioral findings suggest that the development of delinquent behavior is associated with atypical social-affective processing. However, to date, no study has examined neural processes associated with social interactions in severely antisocial adolescents. In this study we investigated the behavioral and neural processes underlying social interactions of juvenile delinquents and a matched control group. Participants played the mini-Ultimatum Game as a responder while in the MRI scanner. Participants rejected unfair offers significantly less when the other player had 'no alternative' compared with a 'fair' alternative, suggesting that they took the intentions of the other player into account. However, this effect was reduced in the juvenile delinquents. The neuroimaging results revealed that juvenile delinquents showed less activation in the temporal parietal junction (TPJ) and inferior frontal gyrus (IFG). However, the groups showed similar activation levels in the dorsal anterior cingulate cortex (dACC) and the right anterior insula (AI) when norms were violated. These results indicate that juvenile delinquents with severe antisocial behavior process norm violations adequately, but may have difficulties with attending spontaneously to relevant features of the social context during interactions.

A neurolaw perspective on psychiatric assessments of criminal responsibility: decision-making, mental disorder, and the brain

In some criminal law cases, the defendant is assessed by a forensic psychiatrist or psychologist within the context of an insanity defense. In this article I argue that specific neuroscientific research can be helpful in improving the quality of such a forensic psychiatric evaluation. This will be clarified in two ways. Firstly, we shall adopt the approach of understanding these forensic assessments as evaluations of the influence of a mental disorder on a defendant's decision-making process. Secondly, I shall point to the fact that researchers in neuroscience have performed various studies over recent years on the influence of specific mental disorders on a patient's decision-making. I argue that such research, especially if modified to decision-making in criminal scenarios, could be very helpful to forensic psychiatric assessments. This kind of research aims to provide insights not merely into the presence of a mental disorder, but also into the actual impact of mental disorders on the decisions defendants have made in regard to their actions.

Neuroeconomics: a bridge for translational research

Neuroeconomic methods combine behavioral economic experiments to parameterize aspects of reward-related decision-making with neuroimaging techniques to record corresponding brain activity. In this introductory article to the current special issue, we propose that neuroeconomics is a potential bridge for translational research in psychiatry for several reasons. First, neuroeconomics-derived theoretical predictions about optimal adaptation in a changing environment provide an objective metric to examine psychopathology. Second, neuroeconomics provides a "multilevel" research approach that combines performance (behavioral) measures with intermediate measures between behavior and neurobiology (e.g., neuroimaging) and uses a common metaphor to describe decision-making across multiple levels of explanation. As such, ecologically valid behavioral paradigms closely mirror the physical mechanisms of reward processing. Third, neuroeconomics provides a platform for investigators from neuroscience, economics, psychiatry, and social and clinical psychology to develop a common language for studying reward-related decision making in psychiatric disorders. Therefore, neuroeconomics can provide promising candidate endophenotypes that might help clarify the basis of high heritability associated with psychiatric disorders and that might, in turn, inform treatment.

"We are also normal humans, you know?" Views and attitudes of juvenile delinquents on antisocial behavior, neurobiology and prevention

This paper presents and discusses the views and attitudes of juvenile delinquents regarding the implications of genomics and neurobiology research findings for the prevention and treatment of antisocial behavior. Scientific developments in these disciplines are considered to be of increasing importance for understanding the causes and the course of antisocial behavior and related mental disorders. High expectations exist with regard to the development of more effective prevention and intervention. Whether this is a desirable development does not only depend on science, but also on the ethical and social implications of potential applications of current and future research findings. As this pilot study points out, juvenile delinquents themselves have rather mixed views on the goals and means of early identification, prevention and treatment. Some welcome the potential support and help that could arise from biologically informed preventive and therapeutic measures. Others, however, reject the very goals of prevention and treatment and express worries concerning the risk of labeling and stigmatization and the possibility of false positives. Furthermore, interventions could aim at equalizing people and taking away socially disapproved capacities they themselves value. Moreover, most juvenile delinquents are hardly convinced that their crime could have been caused by some features of their brain or that a mental disorder has played a role. Instead, they provide social explanations such as living in a deprived neighborhood or having antisocial friends. We suggest that the hopes and expectations as well as the concerns and worries of juvenile delinquents are relevant not only for genomics and neurobiology of antisocial behavior, but also for prevention and intervention measures informed by social scientific and psychological research. The range of patterns of thought of juvenile delinquents is of great heuristic value and may lead to subsequent research that could further enhance our understanding of these patterns.

Externalizing psychopathology and persistence of offending in childhood first-time arrestees

This study aims to investigate the predictive validity of externalizing psychopathology for persistence in delinquent behavior when controlling for socio-demographic and first arrest characteristics in childhood first-time arrestees. A sample of first-time arrestees aged under 12 (n = 192) was assessed using the Diagnostic Interview Schedule for Children (DISC-IV) parent-version on attention deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD) and conduct disorder (CD). Based on child and parent reports of offending as obtained at arrest and at 2-year follow-up, three groups of offenders were differentiated: (1) persistent high (n = 48), (2) occasional (n = 62), and (3) persistent low offenders (n = 82). Over one-third of the sample (33.9%) was diagnosed with an externalizing disorder, and 13.5% with both ADHD and ODD or CD. Higher levels of externalizing psychopathology distinguished persistent high offenders from occasional (comorbid ADHD and ODD/CD: OR 8.2, CI 2.6-25.5) and persistent low offenders (comorbid ADHD and ODD/CD: OR 18.2, CI 4.6-72.3; ADHD: OR 4.1, CI 1.3-13.0), over and above socio-demographic and first offense characteristics. Living with both biological parents distinguished the persistent low offenders from the occasional offenders (OR 2.5, CI 1.2-5.0). Since the prevalence of externalizing disorders was high and predicted re-offending, mental health screening and intervention initiatives, aiming at these conditions, should be investigated for this high-risk sample.

"Better the devil you know": a preliminary study of the differential modulating effects of reputation on reward processing for boys with and without externalizing behavior problems

Very little is known about the neurobiological correlates of reward processing during social decision-making in the developing brain and whether prior social and moral information (reputations) modulates reward responses in youth as has been demonstrated in adults. Moreover, although externalizing behavior problems in youth are associated with deficits in reward processing and social cognition, a real-life social interaction paradigm using functional neuroimaging (fMRI) has not yet been applied to probe reward processing in such youth. Functional neuroimaging was used to examine the neural correlates of reward-related decision-making during a trust task in two samples of age-matched 11 to 16-year-old boys: with (n = 10) and without (n = 10) externalizing behavior problems. The task required subjects to decide whether to share or keep monetary rewards from partners they themselves identified during a real-life peer sociometric procedure as interpersonally aggressive or kind (vs. neutral). Results supported the notion that prior social and moral information (reputations) modulated reward responses in the adolescent brain. Moreover, boys with externalizing problems showed differential activation in the bilateral insula during the decision phase of the game as well as the caudate and anterior insula during the outcome phase of the game. Similar activation in adolescents in response to reward related stimuli as found in adults suggests some developmental continuity in corticostriatal circuits. Group differences are interpreted with caution given the small group sizes in the current study. Notwithstanding this limitation, the study provides preliminary evidence for anomalous reward responses in boys with externalizing behavior problems, thereby providing a possible biological correlate of well-established social-cognitive and reward-related theories of externalizing behavior disorders.

Correlates of self-reported offending in children with a first police contact from distinct socio-demographic and ethnic groups

BACKGROUND

This study aims to identify risk factors for level of offending among childhood offenders from different socio-economic status (SES) neighborhoods and ethnic origins.

METHOD

Three groups of childhood first time police arrestees were studied using standardized instruments for individual and parental characteristics: native Dutch offenders from moderate to high SES neighborhoods, native Dutch offenders from low SES neighborhoods, and offenders of non-Western origin from low SES neighborhoods.

RESULTS

All subgroups showed high rates of externalizing disorders (27.2% to 41.8%) and familial difficulties (25.7% to 50.5%). Few differences between neighborhoods were found in the prevalence and impact of risk factors. However, the impact of some family risk factors on offending seemed stronger in the low SES groups. Regarding ethnical differences, family risk factors were more prevalent among non-Western childhood offenders. However, the association of these factors with level of offending seemed lower in the non-Western low SES group, while the association of some individual risk factors were stronger in the non-Western low SES group. Turning to the independent correlation of risk factors within each of the groups, in the Dutch moderate to high SES group, 23.1% of the variance in level of offending was explained by ADHD and behavioral problems; in the Dutch low SES group, 29.0% of the variance was explained by behavioral problems and proactive aggression; and in the non-Western low SES group, 41.2% of the variance was explained by substance use, sensation seeking, behavioral peer problems, and parental mental health problems.

CONCLUSIONS

Thereby, the study indicates few neighborhood differences in the impact of individual and parental risk factors on offending, while individual and parental risk factors may differ between ethnic groups.

Personality correlates of physiological response to stress among incarcerated juveniles

BACKGROUND

To examine the relationship between personality type and physiological response to stress among juvenile delinquents.

METHODS

Delinquent males (N = 42, mean age 16.5, SD = 1) recruited from a convenience sample at local juvenile detention facility were compared to a male control sample from a local high school (N = 79; mean age 16.1, SD = 0.8). All participants completed the Weinberger Adjustment Inventory and a Stress-Inducing Speech Task during both of which heart rate was measured.

RESULTS

Compared to controls, delinquent youths showed significantly lower heart rates under both free association and stress conditions (p < 0.05) and a lower rate of increase during stressful stimuli (p < 0.05). Among delinquents, those with a non-reactive personality type appeared to show consistently lower levels of physiological arousal as measured by heart rate.

CONCLUSIONS

Delinquents consistently had lower overall levels of arousal as measured by heart rate. In delinquent boys, we also found a persistently low arousal group with a non-reactive psychological pattern. This combination may be a forerunner of future psychopathy or a product of the developmental trajectory that leads to and results from psychopathic behavior.

Research review: DSM-V conduct disorder: research needs for an evidence base

This article charts a strategic research course toward an empirical foundation for the diagnosis of conduct disorder in the forthcoming DSM-V. Since the DSM-IV appeared in 1994, an impressive amount of new information about conduct disorder has emerged. As a result of this new knowledge, reasonable rationales have been put forward for adding to the conduct disorder diagnostic protocol: a childhood-limited subtype, family psychiatric history, callous-unemotional traits, female-specific criteria, preschool-specific criteria, early substance use, and biomarkers from genetics, neuroimaging, and physiology research. This article reviews the evidence for these and other potential changes to the conduct disorder diagnosis. We report that although there is a great deal of exciting research into each of the topics, very little of it provides the precise sort of evidence base required to justify any alteration to the DSM-V. We outline specific research questions and study designs needed to build the lacking evidence base for or against proposed changes to DSM-V conduct disorder.

Structural and functional MRI- findings in children and adolescents with antisocial behavior

BACKGROUND

The developmental course of children with conduct disorder (CD) is heterogeneous. Especially children who exhibit symptoms early in their lifetimes are characterized by a negative outcome. Neurobiological aspects of CD have been investigated in these children but little is known about structural and functional brain aberrations.

METHODS

We describe the developmental taxonomy of children with CD and focus on those with the early onset subtype. Structural MRI data of these children and antisocial adults are recapitulated. The impact of investigating neurobiological underpinnings of antisocial behavior and how this might contribute to future forensic and psychiatric assessments is discussed. RESULTS/ CONCLUSION: Children display similar structural aberrations of fronto-limbic structures to adults with antisocial behavior, and amygdala dysfunction might be closely related to dysregulated emotions. Though the investigation of biological factors in antisocial subjects has made great progress in recent years, today MRI is still a rather complex, expensive and indistinct method for forensic assessment.

Bad nature, bad nurture, and testimony regarding MAOA and SLC6A4 genotyping at murder trials

Recent research-in which subjects were studied longitudinally from childhood until adulthood-has started to clarify how a child's environment and genetic makeup interact to create a violent adolescent or adult. For example, male subjects who were born with a particular allele of the monoamine oxidase A gene and also were maltreated as children had a much greater likelihood of manifesting violent antisocial behavior as adolescents and adults. Also, individuals who were born with particular alleles of the serotonin transporter gene and also experienced multiple stressful life events were more likely to manifest serious depression and suicidality. This research raises the question of whether testimony regarding a defendant's genotype, exposure to child maltreatment, and experience of unusual stress is appropriate to present during the guilt or penalty phases of criminal trials, especially when capital punishment is a consideration. The authors present their experience in genotyping criminal defendants and presenting genetic information at criminal trials.