Research review: the neurobiology and genetics of maltreatment and adversity

MAOA genotype, childhood maltreatment, and their interaction in the etiology of adult antisocial behaviors

BACKGROUND

Maltreatment by an adult or caregiver during childhood is a prevalent and important predictor of antisocial behaviors in adulthood. A functional promoter polymorphism in the monoamine oxidase A (MAOA) gene has been implicated as a moderating factor in the relationship between childhood maltreatment and antisocial behaviors. Although there have been numerous attempts at replicating this observation, results remain inconclusive.

METHODS

We examined this gene-environment interaction hypothesis in a sample of 3356 white and 960 black men (aged 24-34) participating in the National Longitudinal Study of Adolescent Health.

RESULTS

Primary analysis indicated that childhood maltreatment was a significant risk factor for later behaviors that violate rules and the rights of others (p < .05), there were no main effects of MAOA genotype, and MAOA genotype was not a significant moderator of the relationship between maltreatment and antisocial behaviors in our white sample. Post hoc analyses identified a similar pattern of results among our black sample in which maltreatment was not a significant predictor of antisocial behavior. Post hoc analyses also revealed a main effect of MAOA genotype on having a disposition toward violence in both samples and for violent convictions among our black sample. None of these post hoc findings, however, survived correction for multiple testing (p > .05). Power analyses indicated that these results were not due to insufficient statistical power.

CONCLUSIONS

We could not confirm the hypothesis that MAOA genotype moderates the relationship between childhood maltreatment and adult antisocial behaviors.

Violence among people with schizophrenia: phenotypes and neurobiology

People with schizophrenia are at increased risk, as compared to the general population, to acquire convictions for violent crimes and homicide. They also show elevated levels of aggressive behaviour. While psychotic symptoms explain aggressive behaviour that is common during acute episodes, they do not explain such behaviour at other stages of illness or prior to illness onset. Three distinct phenotypes have been identified: individuals with a childhood onset of conduct disorder who display antisocial and aggressive behaviour both before and after schizophrenia onset; individuals with no history of conduct problems who begin engaging in aggressive behaviour as illness onsets; and individuals who after many years of illness engage in a severe physical assault. Little is known about the aetiology of the three types of offenders and about the neural mechanisms that initiate and maintain these behaviours. We hypothesize that schizophrenia preceded by conduct disorder is associated with a combination of genes conferring vulnerability for both disorders and altering the effects of environmental factors on the brain, and thereby, with a distinct pattern of neural development. Some evidence is available to support this hypothesis. By contrast, offending among adults with schizophrenia who have no history of such behaviour prior to illness may result from the changes in the brain that occur as illness onsets, and that are further altered by comorbid conditions such as substance misuse, or by the progressive changes in the brain through adulthood that may result from the illness and from the use of antipsychotic medications.

Childhood maltreatment and corpus callosum volume in recently diagnosed patients with bipolar I disorder: data from the Systematic Treatment Optimization Program for Early Mania (STOP-EM)

Childhood trauma (CT) has been associated with abnormalities in the corpus callosum (CC). Decreased CC volumes have been reported in children and adolescents with trauma as well as adults with CT compared to healthy controls. CC morphology is potentially susceptible to the effects of Bipolar Disorder (BD) itself. Therefore, we evaluated the relationship between CT and CC morphology in BD. We using magnetic resonance imaging in 53 adults with BD recently recovered from their first manic episode, with (n = 23) and without (n = 30) CT, defined using the Childhood Trauma Questionnaire (CTQ) and 16 healthy controls without trauma. ANCOVA was performed with age, gender and intracranial volume as covariates in order to evaluate group differences in CC volume. The total CC volume was found to be smaller in BD patients with trauma compared to BD patients without trauma (p < .05). The differences were more pronounced in the anterior region of the CC. There was a significant negative correlation between CTQ scores and total CC volume in BD patients with trauma (p = .01). We did not find significant differences in the CC volume of patients with/without trauma compared to the healthy subjects. Our sample consists of patients recovered from a first episode of mania and are early in the course of illness and reductions in CC volume may occur late in the course of BD. It might mean there may be two sources of CC volume reduction in these patients: the reduction due to trauma, and the further reduction due to the illness.

Association of DHEA, DHEAS, and cortisol with childhood trauma exposure and post-traumatic stress disorder

There has been a great deal of interest in the role of the neuroendocrine hormones of the hypothalamic-pituitary-adrenal (HPA) axis in the expression of stress-related psychopathology such as post-traumatic stress disorder (PTSD). This investigation examined the association of PTSD and childhood maltreatment with three key HPA axis hormones: cortisol, dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DHEAS). Regression analyses were undertaken on a sample of 43 participants with and 57 participants without PTSD. Results demonstrated that after controlling for age, sex, and PTSD status, exposure to childhood maltreatment was significantly associated with cortisol secretion [F(4,95)=11.68, ΔR(2)=0.11, P=0.0009] and cortisol/DHEA ratio [F(4,95)=6.20, ΔR(2)=0.05, P=0.01]. PTSD status was not associated with any of these neuroendocrine variables. Findings are discussed in the context of the complexity of the relationship of these neuroendocrine variables with trauma exposure and trauma-related psychopathology. It is suggested that DHEA(S) or cortisol/DHEA(S) ratios may not be biomarkers of specific forms of psychopathology per se, but that, instead, the severity and developmental timing of trauma may set the HPA axis in ways that are reflected in interactions among these neuroendocrine hormones. In adulthood, these HPA axis hormones may continue to be dynamically affected by personal and environmental resources.

Neuroimaging in children, adolescents and young adults with psychological trauma

Childhood psychological trauma is a strong predictor of psychopathology. Preclinical research points to the influence of this type of trauma on brain development. However, the effects of psychological trauma on the developing human brain are less known and a challenging question is whether the effects can be reversed or even prevented. The aim of this review is to give an overview of neuroimaging studies in traumatized juveniles and young adults up till 2012. Neuroimaging studies in children and adolescents with traumatic experiences were found to be scarce. Most studies were performed by a small number of research groups in the United States and examined structural abnormalities. The reduction in hippocampal volume reported in adults with PTSD could not be confirmed in juveniles. The most consistent finding in children and adolescents, who experienced psychological trauma are structural abnormalities of the corpus callosum. We could not identify any studies investigating treatment effects. Neuroimaging studies in traumatized children and adolescents clearly lag behind studies in traumatized adults as well as studies on ADHD and autism.

Cortical thickness, surface area, and gyrification abnormalities in children exposed to maltreatment: neural markers of vulnerability?

BACKGROUND

Childhood maltreatment has been shown to significantly elevate the risk of psychiatric disorder. Previous neuroimaging studies of children exposed to maltreatment have reported atypical neural structure in several regions, including the prefrontal cortex and temporal lobes. These studies have exclusively investigated volumetric differences rather than focusing on genetically and developmentally distinct indices of brain structure.

METHODS

Here we used surface-based methods to examine cortical thickness, surface area, and local gyrification in a community sample of children with documented experiences of abuse (n = 22) and a group of carefully matched nonmaltreated peers (n = 21).

RESULTS

Reduced cortical thickness in the maltreated compared with the nonmaltreated group was observed in an extended cluster that incorporated the anterior cingulate, superior frontal gyrus, and orbitofrontal cortex. In addition, reduced cortical surface area was observed within the parcellated regions of the left middle temporal area and lingual gyrus. Local gyrification deficits within the maltreated group were located within two clusters, the lingual gyrus and the insula extending into pars opercularis.

CONCLUSIONS

This is the first time structural abnormalities in the anterior cingulate and lingual gyrus have been detected in children exposed to maltreatment. Surface-based methods seem to capture subtle, previously undetected, morphological abnormalities associated with maltreatment. We suggest that these approaches detect developmental precursors of brain volume differences seen in adults with histories of abuse. Because the reported regions are implicated in several clinical disorders, they might constitute biological markers of vulnerability, linking exposure to early adversity and psychiatric risk.

The neurobiological correlates of childhood adversity and implications for treatment

OBJECTIVE

This article provides an overview of research on the neurobiological correlates of childhood adversity and a selective review of treatment implications.

METHOD

Findings from a broad array of human and animal studies of early adversity were reviewed.

RESULTS

Topics reviewed include neuroendocrine, neurotrophic, neuroimaging, and cognitive effects of adversity, as well as genetic and epigenetic influences. Effects of early-life stress on treatment outcome are considered, and development of treatments designed to address the neurobiological abnormalities is discussed.

CONCLUSION

Early adversity is associated with abnormalities of several neurobiological systems that are implicated in the development of psychopathology and other medical conditions. Early-life stress negatively impacts treatment outcome, and individuals may require treatments that are specific to this condition.

Positive parenting predicts the development of adolescent brain structure: a longitudinal study

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Positive parenting predicts development of adolescent amygdala and prefrontal cortex.

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Positive parenting has a unique influence on adolescent brain development.

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Positive and negative parenting are not opposite sides of a continuum.

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Parenting interventions may promote healthy adolescent brain development.

Little work has been conducted that examines the effects of positive environmental experiences on brain development to date. The aim of this study was to prospectively investigate the effects of positive (warm and supportive) maternal behavior on structural brain development during adolescence, using longitudinal structural MRI. Participants were 188 (92 female) adolescents, who were part of a longitudinal adolescent development study that involved mother–adolescent interactions and MRI scans at approximately 12 years old, and follow-up MRI scans approximately 4 years later. FreeSurfer software was used to estimate the volume of limbic-striatal regions (amygdala, hippocampus, caudate, putamen, pallidum, and nucleus accumbens) and the thickness of prefrontal regions (anterior cingulate and orbitofrontal cortices) across both time points. Higher frequency of positive maternal behavior during the interactions predicted attenuated volumetric growth in the right amygdala, and accelerated cortical thinning in the right anterior cingulate (males only) and left and right orbitofrontal cortices, between baseline and follow up. These results have implications for understanding the biological mediators of risk and protective factors for mental disorders that have onset during adolescence.

Sex-specific prediction of hypothalamic-pituitary-adrenal axis activity by pituitary volume during adolescence: a longitudinal study from 12 to 17 years of age

OBJECTIVE

To investigate the longitudinal relationship between pituitary gland volume (PGV) and parameters of hypothalamic-pituitary-adrenal axis (HPAA) functioning during adolescence.

METHODS

Participants were 49 adolescents (19 girls and 30 boys) selected from a larger longitudinal, population-based study of adolescent development. Assessments were conducted at three time points (S1, S2 and S3). MRI sessions were at S1 (age: M=12.62, SD=0.45 years) and S3 (M=16.48, SD=0.53 years) and multiple assessments of salivary cortisol were undertaken at S2 (M=15.51, SD=0.35 years). PGV was measured via previously validated manual tracing methods, and the cortisol awakening response (CAR) and diurnal slope (DSL) were used as indices of HPAA functioning.

RESULTS

A significant sex-linked interaction was found for PGV at S1 predicting both CAR (p=0.025) and DSL (p=0.009) at S2. Specifically, PGV at S1 significantly predicted CAR (p=0.033) and DSL (p=0.010) in boys only, with no significant results found for girls. Neither CAR nor DSL at S2 predicted growth of PGV from S1 to S3.

CONCLUSIONS

PGV in early adolescence predicted HPAA functioning in mid-adolescent boys but not in girls. The results suggest a significant influence of sex-specific development on the relationship between PGV and HPAA activity and reactivity. The findings have potential implications for understanding and interpreting sex-linked and stress related clinical disorders that emerge during mid-to-late adolescence.

Childhood exposure to violence and lifelong health: clinical intervention science and stress-biology research join forces

Many young people who are mistreated by an adult, victimized by bullies, criminally assaulted, or who witness domestic violence react to this violence exposure by developing behavioral, emotional, or learning problems. What is less well known is that adverse experiences like violence exposure can lead to hidden physical alterations inside a child's body, alterations that may have adverse effects on life-long health. We discuss why this is important for the field of developmental psychopathology and for society, and we recommend that stress-biology research and intervention science join forces to tackle the problem. We examine the evidence base in relation to stress-sensitive measures for the body (inflammatory reactions, telomere erosion, epigenetic methylation, and gene expression) and brain (mental disorders, neuroimaging, and neuropsychological testing). We also review promising interventions for families, couples, and children that have been designed to reduce the effects of childhood violence exposure. We invite intervention scientists and stress-biology researchers to collaborate in adding stress-biology measures to randomized clinical trials of interventions intended to reduce effects of violence exposure and other traumas on young people.

Relational interventions for child maltreatment: past, present, and future perspectives

It is well established that child maltreatment has significant deleterious effects for the individual as well as for society. We briefly review research regarding the impact of child maltreatment on the attachment relationship, highlighting the need for relational interventions for maltreated children and their families to effectively thwart negative developmental cascades that are so often observed in the context of child maltreatment. Next, historical and contemporaneous perspectives on relational interventions for individuals with histories of child maltreatment are discussed, with attention to the empirical evidence for and the current evidence-based status of several relationally based interventions for child maltreatment. Differential sensitivity to the environment is then discussed as a theoretical framework with important implications for interventions for individuals who have been reared in maltreating environments. Current research on neurobiology and maltreatment is then reviewed, with an emphasis on the need for future investigations on genetic variants, epigenetics, and the efficacy of relational interventions for maltreated children. We conclude with a discussion of the tenets of developmental psychopathology, their implications for relational interventions for child maltreatment, and recommendations for advancing the development, provision, and evaluation of relational interventions for individuals with histories of child maltreatment.

Temporal lobe volume abnormalities precede the prodrome: a study of children presenting antecedents of schizophrenia

Distributed abnormalities of gray matter (GM) and white matter (WM) volume characterize individuals experiencing their first episode of schizophrenia. Regions of abnormality are present already, albeit less extensively, during the prodromal phase of illness. This study aimed to determine whether putatively at-risk children, aged 9-12 years, who present multiple antecedents of schizophrenia (ASz), display GM and WM volume abnormalities relative to typically developing (TD) children presenting no antecedents. Structural magnetic resonance images were acquired for 20 ASz children and 20 TD children matched on age, sex, and IQ. Whole-brain differences in GM and WM volume were determined using voxel-based morphometry. Relative to the TD group, ASz children showed significantly decreased GM volume in the right middle temporal gyrus (MTG) and increased GM volume in the left superior-middle temporal gyri (P < 0.05, cluster correction). WM volume was significantly increased in ASz children relative to TD children in a cluster encompassing the left inferior parietal lobe, occipital lobe, and superior temporal gyrus. Post-hoc analyses indicated that these abnormalities were not limited to ASz children who self-reported auditory hallucinations on questionnaire. Our findings suggest that children aged 9-12 years who present multiple ASz are characterized by abnormalities of GM and WM volume in the temporal lobes, comprising a subset of the regions affected in first-episode schizophrenia and in the prodromal phase of illness. These preliminary findings indicate that structural brain abnormalities associated with schizophrenia may be detected in putatively at-risk, preprodromal children. Prospective studies following the brain development of at-risk children are needed.

Negative affect predicts adults' ratings of the current, but not childhood, impact of adverse childhood events

Adverse childhood events (ACE's) have been empirically related to a wide range of negative health and mental health outcomes. However, not all individuals who experience ACE's follow a trajectory of poor outcomes, and not all individuals perceive the impact of ACE's as necessarily negative. The purpose of this study was to investigate positive and negative affect as predictors of adults' ratings of both the childhood and adult impact of their childhood adversity. Self-report data on ACE experiences, including number, severity, and 'impact' were collected from 158 community members recruited on the basis of having adverse childhood experiences. Results indicated that, regardless of event severity and number of different types of adverse events experienced, high levels of negative affect were the strongest predictor of whether the adult impact of the adverse childhood events was rated as negative. All individuals rated the childhood impact of events the same. Implications are discussed.

Developmental timing of child maltreatment and symptoms of depression and suicidal ideation in young adulthood: results from the National Longitudinal Study of Adolescent Health

BACKGROUND

Child maltreatment is a potent risk factor for psychopathology. Although the developmental timing of first exposure to maltreatment is considered important in shaping risk of future psychopathology, no consensus exists on whether earlier or later exposures are more deleterious. This study examines whether age at first exposure to abuse is associated with subsequent depression and suicidal ideation.

METHODS

Data were drawn from the National Longitudinal Study of Adolescent Health (n = 15,701). Timing of first maltreatment exposure was classified using: (1) a crude measure capturing early childhood (ages 0-5), middle childhood (ages 6-10), or adolescence (ages 11-17); and (2) a refined measure capturing infancy (ages 0-2), preschool (ages 3-5), latency (ages 6-8), prepubertal (ages 9-10), pubertal (ages 11-13), or adolescence (ages 14-17). We examined whether timing of first exposure was associated with depression and suicidal ideation in early adulthood in the entire sample and among those exposed to maltreatment.

RESULTS

Respondents exposed to abuse, particularly physical abuse, at any age had a higher odds of depression and suicidal ideation in young adulthood than non-maltreated respondents. Among maltreated respondents, exposure during early childhood (ages 0-5), particularly preschool (ages 3-5), was most strongly associated with depression. Respondents first exposed to physical abuse during preschool had a 77% increase in the odds of depression and those first exposed to sexual abuse during early childhood had a 146% increase in the odds of suicidal ideation compared to respondents maltreated as adolescents.

CONCLUSIONS

Developmental timing of first exposure to maltreatment influences risk for depression and suicidal ideation. Whether these findings are evidence for biologically based sensitive periods requires further study.

Childhood maltreatment and psychopathology affect brain development during adolescence

OBJECTIVE

The hippocampus and amygdala have received much attention with regard to the deleterious effects of childhood maltreatment. However, it is not known if and when these effects emerge during adolescence and whether comorbid psychopathology is more likely to explain these effects. This study investigated whether childhood maltreatment was associated with hippocampal and amygdala development from early to midadolescence and whether the experience of psychopathology during this period mediated the relation.

METHOD

One hundred seventeen (60 male) adolescents, recruited as part of a broader adolescent development study, participated in magnetic resonance imaging assessments during early and midadolescence (mean age at baseline 12.62 years, SD 0.44 years; mean follow-up period 3.78 years, SD 0.20 years), and completed self-report measurements of childhood maltreatment and diagnostic interviews assessing DSM-IV mental disorders.

RESULTS

Childhood maltreatment was associated with larger baseline left hippocampal volumes and retarded growth of the left amygdala over time and was indirectly associated, through the experience of psychopathology, with retarded growth of the left hippocampus and accelerated growth of the left amygdala over time. Exploratory cortical analysis showed that maltreatment influenced thickening of the superior parietal region through the experience of psychopathology.

CONCLUSIONS

Childhood maltreatment was associated with altered brain development during adolescence. The experience of Axis I psychopathology during adolescence may be one mechanism by which childhood maltreatment has continuing effects on brain development during the adolescent years. These findings highlight the importance of early intervention for individuals who have experienced childhood maltreatment.

Structural brain alterations associated with schizophrenia preceded by conduct disorder: a common and distinct subtype of schizophrenia?

Conduct disorder (CD) prior to age 15 is a precursor of schizophrenia in a minority of cases and is associated with violent behavior through adulthood, after taking account of substance misuse. The present study used structural magnetic imaging to examine gray matter (GM) volumes among 27 men with schizophrenia preceded by CD (SZ+CD), 23 men with schizophrenia but without CD (SZ-CD), 27 men with CD only (CD), and 25 healthy (H) men. The groups with schizophrenia were similar in terms of age of onset and duration of illness, levels of psychotic symptoms, and medication. The 2 groups with CD were similar as to number of CD symptoms, lifelong aggressive behavior, and number of criminal convictions. Men with SZ+CD, relative to those with SZ-CD, displayed (1) increased GM volumes in the hypothalamus, the left putamen, the right cuneus/precuneus, and the right inferior parietal cortex after controlling for age, alcohol, and drug misuse and (2) decreased GM volumes in the inferior frontal region. Men with SZ+CD (relative to the SZ-CD group) and CD (relative to the H group) displayed increased GM volumes of the hypothalamus and the inferior and superior parietal lobes, which were not associated with substance misuse. Aggressive behavior, both prior to age 15 and lifetime tendency, was positively correlated with the GM volume of the hypothalamus. Thus, among males, SZ+CD represents a distinct subtype of schizophrenia. Although differences in behavior emerge in childhood and remain stable through adulthood, further research is needed to determine whether the differences in GM volumes result from abnormal neural development distinct from that of other males developing schizophrenia.

Increased serotonin transporter gene (SERT) DNA methylation is associated with bullying victimization and blunted cortisol response to stress in childhood: a longitudinal study of discordant monozygotic twins

BACKGROUND

Childhood adverse experiences are known to induce persistent changes in the hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress. However, the mechanisms by which these experiences shape the neuroendocrine response to stress remain unclear. Method We tested whether bullying victimization influenced serotonin transporter gene (SERT) DNA methylation using a discordant monozygotic (MZ) twin design. A subsample of 28 MZ twin pairs discordant for bullying victimization, with data on cortisol and DNA methylation, were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994-1995 cohort of families with twins.

RESULTS

Bullied twins had higher SERT DNA methylation at the age of 10 years compared with their non-bullied MZ co-twins. This group difference cannot be attributed to the children's genetic makeup or their shared familial environments because of the study design. Bullied twins also showed increasing methylation levels between the age of 5 years, prior to bullying victimization, and the age of 10 years whereas no such increase was detected in non-bullied twins across time. Moreover, children with higher SERT methylation levels had blunted cortisol responses to stress.

CONCLUSIONS

Our study extends findings drawn from animal models, supports the hypothesis that early-life stress modifies DNA methylation at a specific cytosine-phosphate-guanine (CpG) site in the SERT promoter and HPA functioning and suggests that these two systems may be functionally associated.

Longitudinal MRI reveals altered trajectory of brain development during childhood and adolescence in fetal alcohol spectrum disorders

Diffusion tensor imaging (DTI) of brain development in fetal alcohol spectrum disorders (FASD) has revealed structural abnormalities, but studies have been limited by the use of cross-sectional designs. Longitudinal scans can provide key insights into trajectories of neurodevelopment within individuals with this common developmental disorder. Here we evaluate serial DTI and T1-weighted volumetric MRI in a human sample of 17 participants with FASD and 27 controls aged 5-15 years who underwent 2-3 scans each, ∼2-4 years apart (92 scans total). Increases of fractional anisotropy and decreases of mean diffusivity (MD) were observed between scans for both groups, in keeping with changes expected of typical development, but mixed-models analysis revealed significant age-by-group interactions for three major white matter tracts: superior longitudinal fasciculus and superior and inferior fronto-occipital fasciculus. These findings indicate altered developmental progression in these frontal-association tracts, with the FASD group notably showing greater reduction of MD between scans. ΔMD is shown to correlate with reading and receptive vocabulary in the FASD group, with steeper decreases of MD in the superior fronto-occipital fasciculus and superior longitudinal fasciculus between scans correlating with greater improvement in language scores. Volumetric analysis revealed reduced total brain, white, cortical gray, and deep gray matter volumes and fewer significant age-related volume increases in the FASD group, although age-by-group interactions were not significant. Longitudinal DTI indicates delayed white matter development during childhood and adolescence in FASD, which may underlie persistent or worsening behavioral and cognitive deficits during this critical period.

Research review: the role of cytokines in depression in adolescents: a systematic review

BACKGROUND

While cytokines have been implicated in the pathophysiology of depression in adults, the potential role in younger age groups such as adolescents is less clear. This article therefore reviews the literature (a) to explore the relationship between cytokines and depression in adolescents, and (b) to examine how cytokines may be related to adolescent depression in the context of other neurobiological theories of depression.

METHOD

A systematic review of the scientific literature on the subject was conducted in February 2013, searching the Web of Knowledge, PubMed (Medline), PsycInfo and Cochrane electronic databases.

RESULTS

Eighteen studies were identified measuring both depression or depressive symptoms and cytokines or immune markers in adolescents. Adolescents with depression show age-specific characteristics of the immune and inflammatory system, specifically in NK cell activity and in pro-inflammatory cytokines (such as IL-1β and TNF-α). In addition, the role of cytokines in adolescent depression is influenced by neurodevelopment, hormonal changes, stress and trauma.

CONCLUSIONS

There may be differences in the neurobiology of adolescent major depressive disorder (MDD) compared with adult MDD. Increased understanding of the role of cytokines in adolescent MDD may lead to improved outcomes in the treatment of adolescent depression.

Harsh physical punishment in childhood and adult physical health

BACKGROUND

The use of physical punishment is controversial. No studies have comprehensively examined the relationship between physical punishment and several physical health conditions in a nationally representative sample. The current study investigated possible associations between harsh physical punishment (ie, pushing, grabbing, shoving, slapping, and hitting) in the absence of more severe child maltreatment (ie, physical abuse, sexual abuse, emotional abuse, physical neglect, emotional neglect, and exposure to intimate partner violence) and several physical health conditions.

METHODS

Data were from the National Epidemiologic Survey on Alcohol and Related Conditions collected in 2004 and 2005 (n = 34,226 in the current analysis). The survey was conducted with a representative US adult population sample (20 years or older). Eight past year physical health condition categories were assessed. Models were adjusted for sociodemographic variables, family history of dysfunction, and Axis I and II mental disorders.

RESULTS

Harsh physical punishment was associated with higher odds of cardiovascular disease (borderline significance), arthritis, and obesity after adjusting for sociodemographic variables, family history of dysfunction, and Axis I and II mental disorders (adjusted odds ratios ranged from 1.20 to 1.30).

CONCLUSIONS

Harsh physical punishment in the absence of child maltreatment is associated with some physical health conditions in a general population sample. These findings inform the ongoing debate around the use of physical punishment and provide evidence that harsh physical punishment independent of child maltreatment is associated with a higher likelihood of physical health conditions.

Childhood maltreatment and aggressive behaviour in violent offenders with psychopathy

OBJECTIVE

To document experiences of childhood maltreatment among violent offenders with antisocial personality disorder (ASPD) distinguishing between those with and without the syndrome of psychopathy (+P and -P), and to determine whether maltreatment is associated with proactive and reactive aggression.

METHOD

The sample included 10 violent offenders with ASPD+P, 15 violent offenders with ASPD-P, and 15 non offenders. All participants completed interviews with the same forensic psychiatrist focusing on physical, sexual, and emotional abuse prior to age 18 using the Early Trauma Inventory. Aggression was assessed using the Reactive-Proactive Questionnaire.

RESULTS

Violent offenders with ASPD+P reported significantly more severe childhood physical abuse, but not more sexual or emotional abuse, than violent offenders with ASPD-P and non offenders. Psychopathy Checklist-Revised (PCL-R) scores, but not childhood physical abuse, were associated with proactive aggression. Childhood physical abuse was associated with reactive aggression, as was an interaction term indicating that when both PCL-R scores and childhood physical abuse were high, so was reactive aggression.

CONCLUSIONS

Among violent offenders, PCL-R scores were positively associated with proactive aggression, while experiences of childhood maltreatment were not. This finding concurs with previous studies of children and adults and suggests that proactive aggression may be a behavioural marker of psychopathic traits. By contrast, childhood physical abuse was associated with reactive aggression, even among violent offenders with high PCL-R scores. This latter finding suggests a strong influence of childhood physical abuse on the development of reactive aggression that persists over the lifespan.

Maternal Separation during Breastfeeding Induces Gender-Dependent Changes in Anxiety and the GABA-A Receptor Alpha-Subunit in Adult Wistar Rats

Different models of rodent maternal separation (MS) have been used to investigate long-term neurobiological and behavioral changes, associated with early stress. However, few studies have involved the analysis of sex-related differences in central anxiety modulation. This study investigated whether MS during breastfeeding affected adult males and females in terms of anxiety and brain GABA-A receptor-alpha-subunit immunoreactivity. The brain areas analyzed were the amygdale (AM), hippocampus (HP), medial prefrontal cortex (mPFC), medial preoptic area (POA) and paraventricular nucleus (PVN). Rats were housed under a reversed light/dark cycle (lights off at 7∶00 h) with access to water and food ad libitum. Animals underwent MS twice daily during the dark cycle from postnatal day 1 to postnatal day 21. Behavior was tested when rats were 65-70 days old using the elevated plus maze and after brains were treated for immunohistochemistry. We found that separated females spent more time in the open arms and showed more head dipping behavior compared with controls. The separated males spent more time in the center of the maze and engaged in more stretching behavior than the controls. Immunohistochemistry showed that separated females had less immunostained cells in the HP, mPFC, PVN and POA, while separated males had fewer immunolabeled cells in the PFC, PVN and AM. These results could indicate that MS has gender-specific effects on anxiety behaviors and that these effects are likely related to developmental alterations involving GABA-A neurotransmission.

Failure to find association between childhood abuse and cognition in first-episode psychosis patients

This study investigated the relationship between severe childhood abuse and cognitive functions in first-episode psychosis patients and geographically-matched controls. Reports of any abuse were associated with lower scores in the executive function domain in the control group. However, in contrast with our hypothesis, no relationships were found amongst cases.

Socioeconomic and other social stressors and biomarkers of cardiometabolic risk in youth: a systematic review of less studied risk factors

Background

Socioeconomic disadvantage and other social stressors in childhood have been linked with cardiometabolic diseases in adulthood; however the mechanisms underlying these observed associations and the timing of their emergence are unclear. The aim of this review was to evaluate research that examined relationships between socioeconomic disadvantage and other social stressors in relation to less-studied cardiometabolic risk factors among youth, including carbohydrate metabolism-related factors, lipids, and central adiposity.

Methods

We searched PubMed and ISI Web of Science to identify relevant publications between 2001 and 2013.Studies were selected based on 4 criteria: (1) the study examined an association between at least one social or economic stressor and one relevant outcome prior to age 21; (2) the sample originated from a high-income country; (3) the sample was not selected based on a health condition; and (4) a central aim was to evaluate the effect of the social or economic stressor on at least one relevant outcome. Abstracts were screened and relevant publications were obtained and evaluated for inclusion criteria. We abstracted data from selected articles, summarized them by exposures and outcomes, and assigned an evidence grade.

Results

Our search identified 37 publications from 31 studies. Socioeconomic disadvantage was consistently associated with greater central adiposity. Research to date does not provide clear evidence of an association between childhood stressors and lipids or carbohydrate metabolism-related factors.

Conclusions

This review demonstrates a paucity of research on the relationship of socioeconomic disadvantage and other social stressors to lipid and carbohydrate metabolism-related factors in youth. Accordingly, it is not possible to form strong conclusions, particularly with regard to stressors other than socioeconomic disadvantage. Findings are used to inform priorities for future research. An improved understanding of these pathways is critical for identifying novel prevention targets and intervention opportunities to protect the long-term health of children and adolescents.

Annual Research Review: Resilient functioning in maltreated children--past, present, and future perspectives

BACKGROUND

Through a process of probabilistic epigenesis, child maltreatment progressively contributes to compromised adaptation on a variety of developmental domains central to successful adjustment. These developmental failures pose significant risk for the emergence of psychopathology across the life course. In addition to the psychological consequences of maltreatment, a growing body of research has documented the deleterious effects of abuse and neglect on biological processes. Nonetheless, not all maltreated children develop maladaptively. Indeed, some percentage of maltreated children develops in a resilient fashion despite the significant adversity and stress they experience.

METHODS

The literature on the determinants of resilience in maltreated children is selectively reviewed and criteria for the inclusion of the studies are delineated.

RESULTS

The majority of the research on the contributors to resilient functioning has focused on a single level of analysis and on psychosocial processes. Multilevel investigations have begun to appear, resulting in several studies on the processes to resilient functioning that integrate biological/genetic and psychological domains.

CONCLUSIONS

Much additional research on the determinants of resilient functioning must be completed before we possess adequate knowledge based on a multiple levels of analysis approach that is commensurate with the complexity inherent in this dynamic developmental process. Suggestions for future research on the development of resilient functioning in maltreated children are proffered and intervention implications are discussed.

Parental responsiveness moderates the association between early-life stress and reduced telomere length

Early-life stress, such as maltreatment, institutionalization, and exposure to violence, is associated with accelerated telomere shortening. Telomere shortening may thus represent a biomarker of early adversity. Previous studies have suggested that responsive parenting may protect children from the negative biological and behavioral consequences of early adversity. This study examined the role of parental responsiveness in buffering children from telomere shortening following experiences of early-life stress. We found that high-risk children had significantly shorter telomeres than low-risk children, controlling for household income, birth weight, gender, and minority status. Further, parental responsiveness moderated the association between risk and telomere length, with more responsive parenting associated with longer telomeres only among high-risk children. These findings suggest that responsive parenting may have protective benefits on telomere shortening for young children exposed to early-life stress. Therefore, this study has important implications for early parenting interventions.

FKBP5 and emotional neglect interact to predict individual differences in amygdala reactivity

Individual variation in physiological responsiveness to stress mediates risk for mental illness and is influenced by both experiential and genetic factors. Common polymorphisms in the human gene for FK506 binding protein 5 (FKBP5), which is involved in transcriptional regulation of the hypothalamic-pituitary-adrenal (HPA) axis, have been shown to interact with childhood abuse and trauma to predict stress-related psychopathology. In the current study, we examined if such gene-environment interaction effects may be related to variability in the threat-related reactivity of the amygdala, which plays a critical role in mediating physiological and behavioral adaptations to stress including modulation of the HPA axis. To this end, 139 healthy Caucasian youth completed a blood oxygen level-dependent functional magnetic resonance imaging probe of amygdala reactivity and self-report assessments of emotional neglect (EN) and other forms of maltreatment. These individuals were genotyped for 6 FKBP5 polymorphisms (rs7748266, rs1360780, rs9296158, rs3800373, rs9470080 and rs9394309) previously associated with psychopathology and/or HPA axis function. Interactions between each SNP and EN emerged such that risk alleles predicted relatively increased dorsal amygdala reactivity in the context of higher EN, even after correcting for multiple testing. Two different haplotype analyses confirmed this relationship as haplotypes with risk alleles also exhibited increased amygdala reactivity in the context of higher EN. Our results suggest that increased threat-related amygdala reactivity may represent a mechanism linking psychopathology to interactions between common genetic variants affecting HPA axis function and childhood trauma.

Higher in vivo serotonin-1a binding in posttraumatic stress disorder: a PET study with [11C]WAY-100635

BACKGROUND

Brain serotonin-1A receptors (5-HT1A ) are implicated in anxiety. We compared regional brain 5-HT1A binding in medication-free participants with posttraumatic stress disorder (PTSD) and healthy volunteers using fully quantitative positron emission tomography (PET) methods.

METHODS

Twenty patients with DSM-IV PTSD (13 with comorbid major depressive disorder, [MDD]) and 49 healthy volunteers underwent PET imaging with 5-HT1A antagonist radioligand [C-11]WAY100635. Arterial blood sampling provided a metabolite-corrected input function and the concentration of free ligand in plasma (fP ) for estimation of regional binding potential, BPF ( = Bavailable / KD ). Linear mixed modeling compared BPF between groups across regions of interest (ROIs).

RESULTS

The PTSD group had higher 5-HT1A BPF across brain ROIs (P = .0006). Post hoc comparisons showed higher 5-HT1A BPF in PTSD in all cortical ROIs (26-33%), amygdala (34%), and brainstem raphe nuclei (43%), but not hippocampus. The subgroup of seven PTSD patients without comorbid MDD had higher 5-HT1A BPF compared with healthy volunteers (P = .03).

CONCLUSIONS

This is the first report of higher brainstem and forebrain 5-HT1A binding in vivo in PTSD. The finding is independent of MDD. PTSD and MDD have in common an upregulation of 5-HT1A binding including midbrain autoreceptors that would favor less firing and serotonin release. This abnormality may represent a common biomarker of these stress-associated brain disorders.

Predicting the accuracy of facial affect recognition: the interaction of child maltreatment and intellectual functioning

Previous research demonstrates that both child maltreatment and intellectual performance contribute uniquely to the accurate identification of facial affect by children and adolescents. The purpose of this study was to extend this research by examining whether child maltreatment affects the accuracy of facial recognition differently at varying levels of intellectual functioning. A sample of maltreated (n=50) and nonmaltreated (n=56) adolescent females, 14 to 19 years of age, was recruited to participate in this study. Participants completed demographic and study-related questionnaires and interviews to control for potential psychological and psychiatric confounds such as symptoms of posttraumatic stress disorder, negative affect, and difficulties in emotion regulation. Participants also completed an experimental paradigm that recorded responses to facial affect displays starting in a neutral expression and changing into a full expression of one of six emotions: happiness, sadness, anger, disgust, fear, or surprise. Hierarchical multiple regression assessed the incremental advantage of evaluating the interaction between child maltreatment and intellectual functioning. Results indicated that the interaction term accounted for a significant amount of additional variance in the accurate identification of facial affect after controlling for relevant covariates and main effects. Specifically, maltreated females with lower levels of intellectual functioning were least accurate in identifying facial affect displays, whereas those with higher levels of intellectual functioning performed as well as nonmaltreated females. These results suggest that maltreatment and intellectual functioning interact to predict the recognition of facial affect, with potential long-term consequences for the interpersonal functioning of maltreated females.

Resiliency as a mediator of the impact of sleep on child and adolescent behavior

BACKGROUND

Disturbed sleep is detrimental to child behavior; however, the precise means by which this association occurs is unclear. Sleep and resilience can theoretically share an underlying neural mechanism and therefore influence one another. However, the role of resilience in the association between sleep and behavior is not known. The associations between sleep, resilience, and problematic behavior in children and adolescents aged 7-18 years were investigated in this study.

METHODS

A correlational design was used to determine the relationships between total sleep problems, indices of resilience, and internalizing and externalizing behaviors.

RESULTS

Sleep problems and resiliency variables were strongly correlated, and further, sleep problems were found to be predictive of resiliency scores. Resiliency significantly mediated the relationship between increased sleep problems and both overall internalizing and externalizing behavior problems, and specifically, measures of depression and anxiety.

CONCLUSION

Sleep impacted levels of resilience such that greater sleep disturbance reduced resilience and consequently increased problematic behavior, potentially predisposing individuals to psychopathology.

Psychoendocrine and psychoneuroimmunological mechanisms in the comorbidity of atopic eczema and attention deficit/hyperactivity disorder

Epidemiological data indicate that atopic eczema (AE) in infancy significantly increases the risk for attention deficit/hyperactivity disorder (ADHD) in later life. The underlying pathophysiological mechanisms of this comorbidity are unknown. We propose that the release of inflammatory cytokines caused by the allergic inflammation and/or elevated levels of psychological stress as a result of the chronic disease interfere with the maturation of prefrontal cortex regions and neurotransmitter systems involved ADHD pathology. Alternatively, increased stress levels in ADHD patients may trigger AE via neuroimmunological mechanisms. In a third model, AE and ADHD may be viewed as two separate disorders with one or more shared risk factors (e.g., genetics, prenatal stress) that increase the susceptibility for both disorders leading to the co-occurrence of AE and ADHD. Future investigation of these three models may lead to a better understanding of the mechanisms underlying the observed comorbidity between AE and ADHD and further, to targeted interdisciplinary primary prevention and treatment strategies.

The mediating effect of daily stress on the sexual arousal function of women with a history of childhood sexual abuse

Psychopathologies such as posttraumatic stress disorder are often proposed as mediators of the sexual arousal dysfunction experienced by women with a history of childhood maltreatment. However, posttraumatic stress disorder symptoms are only part of the difficulties experienced by these women. Other factors to consider include negative affectivity and perceived daily stress. To assess the mediating role of posttraumatic stress disorder symptoms, negative affectivity, and perceived daily stress, we collected data from 62 women with and without a history of childhood maltreatment (sexual, physical and emotional abuse). A comprehensive assessment of sexual arousal functioning and sexual responses was obtained using self-reported measures and psychophysiological measures of vaginal engorgement and subjective sexual arousal during exposure to sexual visual stimuli. The model assessed the simultaneous mediating effect of posttraumatic stress disorder symptoms, negative affectivity and perceived daily stress on the relation between childhood maltreatment and sexual variables. Daily stress, showed a significant and stronger mediation effect on sexual arousal functioning as compared to posttraumatic stress disorder and negative affectivity. These findings suggest that daily stress may be an important mechanism to consider when treating sexual arousal functioning in women who have a history of childhood maltreatment.

Epigenetics and the social work imperative

Epigenesis is the biochemical process through which some genes are expressed and others remain silent, and it reinforces and explains the powerful impact that the environment has on human development. Epigenetic effects occur not only through diet, chemical exposure, and high levels of environmental stress, but also through chronic poverty and racism. Epigenesis provides a mandate for social workers to intervene at the policy level, both for today's children and for those in future generations.

Epigenetic Modulation of Mood Disorders

BACKGROUND

Mood disorders are expressed in many heterogeneous forms, varying from anxiety to severe major clinical depression. The disorders are expressed in individual variety through manifestations governed by co-morbidities, symptom frequency, severity, and duration, and the effects of genes on phenotypes. The underlying etiologies of mood disorders consist of complex interactive operations of genetic and environmental factors. The notion of endophenotypes, which encompasses the markers of several underlying liabilities to the disorders, may facilitate efforts to detect and define, through staging, the genetic risks inherent to the extreme complexity of disease state.

AIMS

This review evaluates the role of genetic biomarkers in assisting clinical diagnosis, identification of risk factors, and treatment of mood disorders.

METHODS

Through a systematic assessment of studies investigating the epigenetic basis for mood disorders, the present review examines the interaction of genes and environment underlying the pathophysiology of these disorders.

RESULTS

The majority of research findings suggest that the notion of endophenotypes, which encompasses the markers of several underlying liabilities to the disorders, may facilitate efforts to detect and define, through staging, the genetic risks inherent to the extreme complexity of the disease states. Several strategies under development and refinement show the propensity for derivation of essential elements in the etiopathogenesis of the disorders affecting drug-efficacy, drug metabolism, and drug adverse effects, e.g., with regard to selective serotonin reuptake inhibitors. These include: transporter gene expression and genes encoding receptor systems, hypothalamic-pituitary-adrenal axis factors, neurotrophic factors, and inflammatory factors affecting neuroimmune function. Nevertheless, procedural considerations of pharmacogenetics presume the parallel investment of policies and regulations to withstand eventual attempts at misuse, thereby ensuring patient integrity.

CONCLUSIONS

Identification of genetic biomarkers facilitates choice of treatment, prediction of response, and prognosis of outcome over a wide spectrum of symptoms associated with affective states, thereby optimizing clinical practice procedures. Epigenetic regulation of primary brain signaling, e.g., serotonin and hypothalamic-pituitary-adrenal function, and factors governing their metabolism are necessary considerations. The participation of neurotrophic factors remains indispensable for neurogenesis, survival, and functional maintenance of brain systems.

Depression in elderly persons subject to childhood maltreatment is not modulated by corpus callosum and hippocampal loss

Childhood adversity has been observed to engender structural changes in the hippocampus and corpus callosum associated with increased risk for depression in childhood and early adulthood. This study investigated this association in the elderly. Corpus callosum area and hippocampal volume were measured from structural MRI in 427 community dwelling elderly. Information on childhood adversity was obtained in the course of a clinical examination using a questionnaire covering multiple aspects of abuse. Multivariate analyses found a significant increase in corpus callosum area and hippocampal volume in subjects exposed to mental disorder in parents and poverty, respectively. No association was found with childhood sexual and physical abuse.

Treatment of childhood sexual abuse: an updated review

Childhood sexual abuse (CSA) involves multiple complex factors that make the evaluation of therapeutic interventions especially complicated. PTSD prevalence rates of CSA are approximately 37 % -53 %. Several other psychiatric sequelae of CSA exist. CSA appears to disrupt brain and body physiology. One co-located service delivery model reported a 52 % linkage rate of CSA survivors with mental health treatment. This article reviews current literature on the treatment of CSA, including psychosocial interventions, pharmacotherapy, and early preventative interventions. It also provides an update on the short- and long-term sequelae of CSA and implications for future research directions. A literature search of papers published in the last 3 years was conducted using the keywords treatment, sexual abuse, childhood, epigenetics, resilience and review, and searching the following databases: PsycInfo, PubMed, Substance Abuse and Mental Health Services Administration, and Centers for Disease Control.

A consideration of select pre-trauma factors as key vulnerabilities in PTSD

Posttraumatic stress disorder (PTSD) is a pathological response to a traumatic event. A number of risk and vulnerability factors predicting PTSD development have been identified in the literature. Many of these variables are specific factors occurring during and after exposure to a traumatic event or are not measured prospectively to assess temporal sequence. Recent research, however, has begun to focus on pre-trauma individual differences that could contribute to risk for developing PTSD. The present review proposes that a number of biological and cognitive vulnerability factors place individuals at risk for PTSD development prior to the actual experience of trauma. Accordingly, this review provides a summary of evidence for a select number of these factors as pre-trauma vulnerabilities to PTSD. Included is a discussion of biological factors, including molecular genetic studies of systems regulating serotonin, catecholamines, and glucocorticoids as well as aspects of the neuroendocrine system. Specific cognitive factors are also considered, including intelligence, neuropsychological functioning and cognitive biases such as negative attributional style and appraisals. For each factor, the present review summarizes evidence to date regarding PTSD vulnerability and highlights directions for future research in this area.

An intricate dance: Life experience, multisystem resiliency, and rate of telomere decline throughout the lifespan

Accumulation of life stressors predicts accelerated development and progression of diseases of aging. Telomere length, the DNA-based biomarker indicating cellular aging, is a mechanism of disease development, and is shortened in a dose response fashion by duration and severity of life stressor exposures. Telomere length captures the interplay between genetics, life experiences and psychosocial and behavioral factors. Over the past several years, psychological stress resilience, healthy lifestyle factors, and social connections have been associated with longer telomere length and it appears that these factors can protect individuals from stress-induced telomere shortening. In the current review, we highlight these findings, and illustrate that combining these `multisystem resiliency' factors may strengthen our understanding of aging, as these powerful factors are often neglected in studies of aging. In naturalistic studies, the effects of chronic stress exposure on biological pathways are rarely main effects, but rather a complex interplay between adversity and resiliency factors. We suggest that chronic stress effects can be best understood by directly testing if the deleterious effects of stress on biological aging processes, in this case the cell allostasis measure of telomere shortening, are mitigated in individuals with high levels of multisystem resiliency. Without attending to such interactions, stress effects are often masked and missed. Taking account of the cluster of positive buffering factors that operate across the lifespan will take us a step further in understanding healthy aging. While these ideas are applied to the telomere length literature for illustration, the concept of multisystem resiliency might apply to aging broadly, from cellular to systemic health.

White matter disruptions in adolescents exposed to childhood maltreatment and vulnerability to psychopathology

Childhood maltreatment has been known to produce long-lasting impairments in behavioral, cognitive and social functioning, but their underlying mechanisms are not well-understood. A better understanding of their underlying mechanisms will aid in developing effective preventive interventions. Nineteen adolescent volunteers with no personal history of a psychiatric illness, but who were exposed to maltreatment during childhood, and 13 adolescent volunteers with no personal or family history of a psychiatric disorder (controls) underwent diffusion tensor imaging (DTI) studies. The participants were then followed longitudinally at 6-month intervals for up to 5 years to determine the onset of mood and substance use disorders. The associations among fractional anisotropy (FA) values obtained from the DTI scans at baseline and psychopathology at follow-up were examined. At baseline, adolescents exposed to childhood maltreatment had significantly lower FA values in the left and right superior longitudinal fasciculi, right cingulum bundle projecting to the hippocampus, left inferior fronto-occipital fasciculus, and splenium of the corpus callosum compared with controls. Adolescents who developed major depressive disorder at follow-up had significantly lower FA values in the superior longitudinal fasciculi and the right cingulum-hippocampal projection compared with their counterparts who did not develop the illness. Adolescents who developed substance use disorder during follow-up had significantly lower FA values in the right cingulum-hippocampal projection than their counterparts without the disorder. These preliminary results suggest that white matter disruptions observed in adolescents exposed to childhood maltreatment may be associated with increased vulnerability to psychopathology, specifically depressive and substance use disorders.

Early life adversity reduces stress reactivity and enhances impulsive behavior: implications for health behaviors

Altered reactivity to stress, either in the direction of exaggerated reactivity or diminished reactivity, may signal a dysregulation of systems intended to maintain homeostasis and a state of good health. Evidence has accumulated that diminished reactivity to psychosocial stress may signal poor health outcomes. One source of diminished cortisol and autonomic reactivity is the experience of adverse rearing during childhood and adolescence. The Oklahoma Family Health Patterns Project has examined a cohort of 426 healthy young adults with and without a family history of alcoholism. Regardless of family history, persons who had experienced high degrees of adversity prior to age 16 had a constellation of changes including reduced cortisol and heart rate reactivity, diminished cognitive capacity, and unstable regulation of affect, leading to behavioral impulsivity and antisocial tendencies. We present a model whereby this constellation of physiological, cognitive, and affective tendencies is consistent with altered central dopaminergic activity leading to changes in brain function that may foster impulsive and risky behaviors. These in turn may promote greater use of alcohol other drugs along with adopting poor health behaviors. This model provides a pathway from early life adversity to low stress reactivity that forms a basis for risky behaviors and poor health outcomes.

Genetic load is associated with hypothalamic-pituitary-adrenal axis dysregulation in macaques

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis pathway is associated with several neuropsychiatric disorders, including post-traumatic stress disorder (PTSD), major depressive disorder (MDD), schizophrenia and alcohol abuse. Studies have demonstrated an association between HPA axis dysfunction and gene variants within the cortisol, serotonin and opioid signaling pathways. We characterized polymorphisms in genes linked to these three neurotransmitter pathways and tested their potential interactions with HPA axis activity, as measured by dexamethasone (DEX) suppression response. We determined the percent DEX suppression of adrenocorticotropic hormone (ACTH) and cortisol in 62 unrelated, male rhesus macaques. While DEX suppression of cortisol was robust amongst 87% of the subjects, ACTH suppression levels were broadly distributed from -21% to 66%. Thirty-seven monkeys from the high and low ends of the ACTH suppression distribution (18 'high' and 19 'low' animals) were genotyped at selected polymorphisms in five unlinked genes (rhCRH, rhTPH2, rhMAOA, rhSLC6A4 and rhOPRM). Associations were identified between three variants (rhCRH-2610C>T, rhTPH2 2051A>C and rh5-HTTLPR) and level of DEX suppression of ACTH. In addition, a significant additive effect of the 'risk' genotypes from these three loci was detected, with an increasing number of 'risk' genotypes associated with a blunted ACTH response (P = 0.0009). These findings suggest that assessment of multiple risk alleles in serotonin and cortisol signaling pathway genes may better predict risk for HPA axis dysregulation and associated psychiatric disorders than the evaluation of single gene variants alone.

Interacting effect of BDNF Val66Met polymorphism and stressful life events on adolescent depression

There is a strong etiological link between brain-derived neurotrophic factor and depression, but the neurocellular mechanisms and gene-environment interactions remain obscure. This study investigated whether one functional polymorphism in the brain-derived neurotrophic factor gene (BDNF Val66Met) modulates the influence of stressful life events on adolescent depressive symptoms. A total of 780 pairs of ethnic Han Chinese adolescent twins, 11-17 years of age, were randomly assigned to one of two subgroups (twin1 and twin2). All subjects were genotyped as Val/Val, Val/Met or Met/Met, and assessed for depressive symptoms using the Children's Depression Inventory. The level of environmental stress was estimated by the frequency of stressful life events using the Life Events Checklist. The frequency of stressful life events was significantly correlated with depressive symptoms (twin1: β = 0.21, P = 0.01; twin2: β = 0.27, P < 0.01), but there was no significant main effect of the BDNF Val66Met genotype on depressive symptoms. In both subgroups, however, the interaction between the BDNF Val66Met genotype and stressful life event frequency was significant (twin1: β = 0.19, P = 0.01; twin2: β = 0.15, P = 0.04); individuals with one or two Val alleles demonstrated a greater susceptibility to both the detrimental effects of higher stress and the beneficial effects of lower stress compared to the Met/Met genotype. These findings support the 'differential-susceptibility' hypothesis, whereby the BDNF Val allele modulates the influence of environmental stress on depression by enhancing the neuroplastic response to all life events.

Reduced thalamic volume in men with antisocial personality disorder or schizophrenia and a history of serious violence and childhood abuse

OBJECTIVE

Violent behaviour has been associated with presence of certain mental disorders, most notably antisocial personality disorder (ASPD) and schizophrenia, childhood abuse, and multiple brain abnormalities. This study examined for the first time, to the authors' knowledge, the role of psychosocial deprivation (PSD), including childhood physical and sexual abuse, in structural brain volumes of violent individuals with ASPD or schizophrenia.

METHODS

Fifty-six men (26 with ASPD or schizophrenia and a history of serious violence, 30 non-violent) underwent magnetic resonance imaging and were assessed on PSD. Stereological volumetric brain ratings were examined for group differences and their association with PSD ratings. PSD-brain associations were examined further using voxel-based-morphometry.

RESULTS

The findings revealed: reduced thalamic volume in psychosocially-deprived violent individuals, relative to non-deprived violent individuals and healthy controls; negative association between thalamic volume and abuse ratings (physical and sexual) in violent individuals; and trend-level negative associations between PSD and hippocampal and prefrontal volumes in non-violent individuals. The voxel-based-morphometry analysis detected a negative association between PSD and localised grey matter volumes in the left inferior frontal region across all individuals, and additionally in the left middle frontal and precentral gyri in non-violent individuals.

CONCLUSIONS

Violent mentally-disordered individuals with PSD, relative to those with no or minimal PSD, suffer from an additional brain deficit, i.e., reduced thalamic volume; this may affect sensory information processing, and have implications for management, of these individuals. PSD may have a stronger relationship with volumetric loss of stress-linked regions, namely the frontal cortex, in non-violent individuals.