Behavioral inhibition and developmental risk: a dual-processing perspective

Behavioral inhibition (BI) is an early-appearing temperament characterized by strong reactions to novelty. BI shows a good deal of stability over childhood and significantly increases the risk for later diagnosis of social anxiety disorder (SAD). Despite these general patterns, many children with high BI do not go on to develop clinical, or even subclinical, anxiety problems. Therefore, understanding the cognitive and neural bases of individual differences in developmental risk and resilience is of great importance. The present review is focused on the relation of BI to two types of information processing: automatic (novelty detection, attention biases to threat, and incentive processing) and controlled (attention shifting and inhibitory control). We propose three hypothetical models (Top-Down Model of Control; Risk Potentiation Model of Control; and Overgeneralized Control Model) linking these processes to variability in developmental outcomes for BI children. We argue that early BI is associated with an early bias to quickly and preferentially process information associated with motivationally salient cues. When this bias is strong and stable across development, the risk for SAD is increased. Later in development, children with a history of BI tend to display normative levels of performance on controlled attention tasks, but they demonstrate exaggerated neural responses in order to do so, which may further potentiate risk for anxiety-related problems. We conclude by discussing the reviewed studies with reference to the hypothetical models and make suggestions regarding future research and implications for treatment.

The neural correlates of emotional face-processing in adolescent depression: a dimensional approach focusing on anhedonia and illness severity

Deficits in emotion processing, a known clinical feature of major depressive disorder (MDD), have been widely investigated using emotional face paradigms and neuroimaging. However, most studies have not accounted for the high inter-subject variability of symptom severity. Similarly, only sparse research has focused on MDD in adolescence, early in the course of the illness. Here we sought to investigate neural responses to emotional faces using both categorical and dimensional analyses with a focus on anhedonia, a core symptom of MDD associated with poor outcomes. Nineteen medication-free depressed adolescents and 18 healthy controls (HC) were scanned during presentation of happy, sad, fearful, and neutral faces. ANCOVAs and regressions assessed group differences and relationships with illness and anhedonia severity, respectively. Findings included a group by valence interaction with depressed adolescents exhibiting decreased activity in the superior temporal gyrus (STG), putamen and premotor cortex. Post-hoc analyses confirmed decreased STG activity in MDD adolescents. Dimensional analyses revealed associations between illness severity and altered responses to negative faces in prefrontal, cingulate, striatal, and limbic regions. However, anhedonia severity was uniquely correlated with responses to happy faces in the prefrontal, cingulate, and insular regions. Our work highlights the need for studying specific symptoms dimensionally in psychiatric research.

Conduct disorder and callous-unemotional traits in youth

The term “conduct problems” refers to a pattern of repetitive rule-breaking behavior, aggression, and disregard for others. Such problems have received increased attention recently, owing to violent events perpetrated by youth and modifications in the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria for conduct disorder, a syndrome involving recurrent conduct problems in children and adolescents. Youth conduct problems are predictive of an increased risk of substance abuse, criminal behavior, and educational disruption; they also incur a considerable societal burden from interpersonal suffering and financial costs. This review summarizes current data on youth conduct problems and highlights promising avenues for research. Prior reviews have summarized either the clinical literature on outcome, treatment, and familial aggregation or the neurocognitive literature on mechanisms and pathophysiology.^– The current review differs by more tightly integrating clinical and neurocognitive perspectives.

Oxytocin and vasopressin modulate risk-taking

The modulation of risk-taking is critical for adaptive and optimal behavior. This study examined how oxytocin (OT) and arginine vasopressin (AVP) influence risk-taking in function of three parameters: sex, risk-valence, and social context. Twenty-nine healthy adults (14 males) completed a risk-taking task, the Stunt task, both in a social-stress (evaluation by unfamiliar peers) and non-social context, in three separate drug treatment sessions. During each session, one of three drugs, OT, AVP, or placebo (PLC), was administered intra-nasally. OT and AVP relative to PLC reduced betting-rate (risk-averse effect). This risk-averse effect was further qualified: AVP reduced risk-taking in the positive risk-valence (high win-probability), and regardless of social context or sex. In contrast, OT reduced risk-taking in the negative risk-valence (low win-probability), and only in the social-stress context and men. The reduction in risk-taking might serve a role in defensive behavior. These findings extend the role of these neuromodulators to behaviors beyond the social realm. How the behavioral modulation of risk-taking maps onto the function of the neural targets of OT and AVP may be the next step in this line of research.

Parametric modulation of neural activity during face emotion processing in unaffected youth at familial risk for bipolar disorder

OBJECTIVES

Both patients with pediatric bipolar disorder (BD) and unaffected youth at familial risk (AR) for the illness show impairments in face emotion labeling. Few studies, however, have examined brain regions engaged in AR youth when processing emotional faces. Moreover, studies have yet to explore neural responsiveness to subtle changes in face emotion in AR youth.

METHODS

Sixty-four unrelated youth, including 20 patients with BD, 15 unaffected AR youth, and 29 healthy comparisons (HC), completed functional magnetic resonance imaging. Neutral faces were morphed with angry or happy faces in 25% intervals. In specific phases of the task, youth alternatively made explicit (hostility) or implicit (nose width) ratings of the faces. The slope of blood oxygenated level-dependent activity was calculated across neutral to angry and neutral to happy face stimuli.

RESULTS

Behaviorally, both subjects with BD (p ≤ 0.001) and AR youth (p ≤ 0.05) rated faces as less hostile relative to HC. Consistent with this, in response to increasing anger on the face, patients with BD and AR youth showed decreased modulation in the amygdala and inferior frontal gyrus (IFG; BA 46) compared to HC (all p ≤ 0.05). Amygdala dysfunction was present across both implicit and explicit rating conditions, but IFG modulation deficits were specific to the explicit condition. With increasing happiness, AR youth showed aberrant modulation in the IFG, which was also sensitive to task demands (all p ≤ 0.05).

CONCLUSIONS

Decreased amygdala and IFG modulation in patients with BD and AR youth may be pathophysiological risk markers for BD, and may underlie the social cognition and face emotion labeling deficits observed in BD and AR youth.

Neural changes with attention bias modification for anxiety: a randomized trial

Attention bias modification (ABM) procedures typically reduce anxiety symptoms, yet little is known about the neural changes associated with this behavioral treatment. Healthy adults with high social anxiety symptoms (n = 53) were randomized to receive either active or placebo ABM. Unlike placebo ABM, active ABM aimed to train individuals' attention away from threat. Using the dot-probe task, threat-related attention bias was measured during magnetic resonance imaging before and after acute and extended training over 4 weeks. A subset of participants completed all procedures (n = 30, 15 per group). Group differences in neural activation were identified using standard analyses. Linear regression tested predictive factors of symptom reduction (i.e., training group, baseline indices of threat bias). The active and placebo groups exhibited different patterns of right and left amygdala activation with training. Across all participants irrespective of group, individuals with greater left amygdala activation in the threat-bias contrast prior to training exhibited greater symptom reduction. After accounting for baseline amygdala activation, greater symptom reduction was associated with assignment to the active training group. Greater left amygdala activation at baseline predicted reductions in social anxiety symptoms following ABM. Further research is needed to clarify brain-behavior mechanisms associated with ABM training.

Evaluating the risks of clinical research: direct comparative analysis

OBJECTIVES

Many guidelines and regulations allow children and adolescents to be enrolled in research without the prospect of clinical benefit when it poses minimal risk. However, few systematic methods exist to determine when research risks are minimal. This situation has led to significant variation in minimal risk judgments, raising concern that some children are not being adequately protected. To address this concern, we describe a new method for implementing the widely endorsed "risks of daily life" standard for minimal risk. This standard defines research risks as minimal when they do not exceed the risks posed by daily life activities or routine examinations.

METHODS

This study employed a conceptual and normative analysis, and use of an illustrative example.

RESULTS

Different risks are composed of the same basic elements: Type, likelihood, and magnitude of harm. Hence, one can compare the risks of research and the risks of daily life by comparing the respective basic elements with each other. We use this insight to develop a systematic method, direct comparative analysis, for implementing the "risks of daily life" standard for minimal risk. The method offers a way of evaluating research procedures that pose the same types of risk as daily life activities, such as the risk of experiencing anxiety, stress, or other psychological harm. We thus illustrate how direct comparative analysis can be applied in practice by using it to evaluate whether the anxiety induced by a respiratory CO2 challenge poses minimal or greater than minimal risks in children and adolescents.

CONCLUSIONS

Direct comparative analysis is a systematic method for applying the "risks of daily life" standard for minimal risk to research procedures that pose the same types of risk as daily life activities. It thereby offers a method to protect children and adolescents in research, while ensuring that important studies are not blocked because of unwarranted concerns about research risks.

Cognitive control moderates early childhood temperament in predicting social behavior in 7-year-old children: an ERP study

Behavioral inhibition (BI) is a temperament associated with heightened vigilance and fear of novelty in early childhood, and social reticence and increased risk for anxiety problems later in development. However, not all behaviorally inhibited children develop signs of anxiety. One mechanism that might contribute to the variability in developmental trajectories is the recruitment of cognitive-control resources. The current study measured N2 activation, an ERP (event-related potential) associated with cognitive control, and modeled source-space activation (LORETA; Low Resolution Brain Electromagnetic Tomography) at 7 years of age while children performed a go/no-go task. Activation was estimated for the entire cortex and then exported for four regions of interest: ventromedial prefrontal cortex (VMPFC), ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dorsal ACC), and dorsal lateral prefrontal cortex (DLPFC). BI was measured in early childhood (ages 2 and 3 years). Anxiety problems and social reticence were measured at 7 years of age to ascertain stability of temperamental style. Results revealed that BI was associated with increased performance accuracy, longer reaction times, greater (more negative) N2 activation, and higher estimated dorsal ACC and DLPFC activation. Furthermore, early BI was only associated with social reticence at age 7 at higher (more negative) levels of N2 activation or higher estimated dorsal ACC or DLPFC activation. Results are discussed in the context of overcontrolled behavior contributing to social reticence and signs of anxiety in middle childhood.

Age-related changes in the intrinsic functional connectivity of the human ventral vs. dorsal striatum from childhood to middle age

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Striatal resting state iFC in 106 healthy individuals ranging from 9 to 44 years.

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Findings cohere with a dorsal–ventral functional dissociation of the striatum.

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Ventral striatal (VS) iFC with insula and anterior cingulate decreased with age.

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Dorsal striatal (DS) iFC with posterior cingulate increased with age.

The striatum codes motivated behavior. Delineating age-related differences within striatal circuitry can provide insights into neural mechanisms underlying ontogenic behavioral changes and vulnerabilities to mental disorders. To this end, a dual ventral/dorsal model of striatal function was examined using resting state intrinsic functional connectivity (iFC) imaging in 106 healthy individuals, ages 9–44. Broadly, the dorsal striatum (DS) is connected to prefrontal and parietal cortices and contributes to cognitive processes; the ventral striatum (VS) is connected to medial orbitofrontal and anterior cingulate cortices, and contributes to affective valuation and motivation. Findings revealed patterns of age-related changes that differed between VS and DS iFCs. We found an age-related increase in DS iFC with posterior cingulate cortex (pCC) that stabilized after the mid-twenties, but a decrease in VS iFC with anterior insula (aIns) and dorsal anterior cingulate cortex (dACC) that persisted into mid-adulthood. These distinct developmental trajectories of VS vs. DS iFC might underlie adolescents’ unique behavioral patterns and vulnerabilities to psychopathology, and also speaks to changes in motivational networks that extend well past 25 years old.

Evolutionarily conserved prefrontal-amygdalar dysfunction in early-life anxiety

Some individuals are endowed with a biology that renders them more reactive to novelty and potential threat. When extreme, this anxious temperament (AT) confers elevated risk for the development of anxiety, depression and substance abuse. These disorders are highly prevalent, debilitating and can be challenging to treat. The high-risk AT phenotype is expressed similarly in children and young monkeys and mechanistic work demonstrates that the central (Ce) nucleus of the amygdala is an important substrate. Although it is widely believed that the flow of information across the structural network connecting the Ce nucleus to other brain regions underlies primates' capacity for flexibly regulating anxiety, the functional architecture of this network has remained poorly understood. Here we used functional magnetic resonance imaging (fMRI) in anesthetized young monkeys and quietly resting children with anxiety disorders to identify an evolutionarily conserved pattern of functional connectivity relevant to early-life anxiety. Across primate species and levels of awareness, reduced functional connectivity between the dorsolateral prefrontal cortex, a region thought to play a central role in the control of cognition and emotion, and the Ce nucleus was associated with increased anxiety assessed outside the scanner. Importantly, high-resolution 18-fluorodeoxyglucose positron emission tomography imaging provided evidence that elevated Ce nucleus metabolism statistically mediates the association between prefrontal-amygdalar connectivity and elevated anxiety. These results provide new clues about the brain network underlying extreme early-life anxiety and set the stage for mechanistic work aimed at developing improved interventions for pediatric anxiety.

Perturbed threat monitoring following a traumatic event predicts risk for post-traumatic stress disorder

BACKGROUND

Post-traumatic stress disorder (PTSD) is a chronic and difficult to treat psychiatric disorder. Objective, performance-based diagnostic markers that uniquely index risk for PTSD above and beyond subjective self-report markers could inform attempts to improve prevention and early intervention. We evaluated the predictive value of threat-related attention bias measured immediately after a potentially traumatic event, as a risk marker for PTSD at a 3-month follow-up. We measured the predictive contribution of attentional threat bias above and beyond that of the more established marker of risk for PTSD, self-reported psychological dissociation.

METHOD

Dissociation symptoms and threat-related attention bias were measured in 577 motor vehicle accident (MVA) survivors (mean age = 35.02 years, 356 males) within 24 h of admission to an emergency department (ED) of a large urban hospital. PTSD symptoms were assessed at a 3-month follow-up using the Clinician-Administered PTSD Scale (CAPS).

RESULTS

Self-reported dissociation symptoms significantly accounted for 16% of the variance in PTSD at follow-up, and attention bias toward threat significantly accounted for an additional 4% of the variance in PTSD.

CONCLUSIONS

Threat-related attention bias can be reliably measured in the context of a hospital ED and significantly predicts risk for later PTSD. Possible mechanisms underlying the association between threat bias following a potentially traumatic event and risk for PTSD are discussed. The potential application of an attention bias modification treatment (ABMT) tailored to reduce risk for PTSD is suggested.

Attention bias to threat faces in severe mood dysregulation

BACKGROUND

We used a dot-probe paradigm to examine attention bias toward threat (i.e., angry) and happy face stimuli in severe mood dysregulation (SMD) versus healthy comparison (HC) youth. The tendency to allocate attention to threat is well established in anxiety and other disorders of negative affect. SMD is characterized by the negative affect of irritability, and longitudinal studies suggest childhood irritability predicts adult anxiety and depression. Therefore, it is important to study pathophysiologic connections between irritability and anxiety disorders.

METHODS

SMD patients (N = 74) and HC youth (N = 42) completed a visual probe paradigm to assess attention bias to emotional faces. Diagnostic interviews were conducted and measures of irritability and anxiety were obtained in patients.

RESULTS

SMD youth differed from HC youth in having a bias toward threatening faces (P < .01). Threat bias was positively correlated with the severity of the SMD syndrome and depressive symptoms; degree of threat bias did not differ between SMD youth with and without co-occurring anxiety disorders or depression. SMD and HC youth did not differ in bias toward or away from happy faces.

CONCLUSIONS

SMD youth demonstrate an attention bias toward threat, with greater threat bias associated with higher levels of SMD symptom severity. Our findings suggest that irritability may share a pathophysiological link with anxiety and depressive disorders. This finding suggests the value of exploring further whether attention bias modification treatments that are effective for anxiety are also helpful in the treatment of irritability.

Irritability in child and adolescent anxiety disorders

BACKGROUND

Our objective was to compare self- and parent-reported irritability in youths with anxiety disorders, healthy youths, and those with mood disorders characterized by irritability. Irritability is a common but relatively understudied psychiatric symptom in child and adolescent anxiety disorders. In anxious youths, little is known about the severity of irritability, its impact on functioning, or the effect of informant source on reports of irritability.

METHODS

We compared parent- and self-report forms of the Affective Reactivity Index (ARI), a validated measure of irritability, in youths ages 8-17 years with no psychopathology (healthy comparison, HC; n = 38), anxiety disorders (ANX; n = 42), bipolar disorder (BD; n = 35), or severe mood dysregulation (SMD; n = 61; a phenotype characterized by chronic, severely impairing irritability).

RESULTS

Irritability was significantly higher in ANX than HC youths by both parent and self-report (partial η(2) = 0.24 and 0.22, respectively, P's < 0.001). Informant effects differed among ANX, BD, and SMD. Overall, parent-reported irritability was higher in BD with comorbid anxiety disorders and SMD with or without comorbid anxiety disorders than ANX (P's < 0.007), but self-reported irritability was not significantly different among the three patient groups.

DISCUSSION

By both parent and self-report, youths with anxiety disorders exhibit significantly more irritability and associated impairment than healthy subjects. Self-reported irritability in youths with anxiety disorders is comparable to that observed in youths with severe mood disorders, although parental reports of irritability differ among the disorders. Future research should examine the pathophysiology of anxiety-associated irritability, as well as its prognostic and treatment implications.

Generalized anxiety disorder is associated with overgeneralization of classically conditioned fear

BACKGROUND

Meta-analytic results of fear-conditioning studies in the anxiety disorders implicate generalization of conditioned fear to stimuli resembling the conditioned danger cue as one of the more robust conditioning markers of anxiety pathology. Due to the absence of conditioning studies assessing generalization in generalized anxiety disorder (GAD), results of this meta-analysis do not reveal whether such generalization abnormalities also apply to GAD. The current study fills this gap by behaviorally and psychophysiologically assessing levels of conditioned fear generalization across adults with and without GAD.

METHODS

Twenty-two patients with a DSM-IV-Text Revision diagnosis of GAD and 26 healthy comparison subjects were recruited and tested. The employed generalization paradigm consisted of quasi-randomly presented rings of gradually increasing size, with extreme sizes serving as conditioned danger cues (CS+) and conditioned safety cues. The rings of intermediary size served as generalization stimuli, creating a continuum of similarity between CS+ and conditioned safety cues across which to assess response slopes, referred to as generalization gradients. Primary outcome variables included slopes for fear-potentiated startle (electromyography) and self-reported risk ratings.

RESULTS

Behavioral and psychophysiological findings demonstrated overgeneralization of conditioned fear among patients with GAD. Specifically, generalization gradients were abnormally shallow among GAD patients, reflecting less degradation of the conditioned fear response as the presented stimulus differentiated from the CS+.

CONCLUSIONS

Overgeneralization of conditioned fear to safe encounters resembling feared situations may contribute importantly to the psychopathology of GAD by proliferating anxiety cues in the individual's environment that are then capable of evoking and maintaining anxiety and worry associated with GAD.

Identification of emotional facial expressions among behaviorally inhibited adolescents with lifetime anxiety disorders

The current study examined differences in emotion expression identification between adolescents characterised with behavioural inhibition (BI) in childhood with and without a lifetime history of anxiety disorder. Participants were originally assessed for BI during toddlerhood and for social reticence during childhood. During adolescence, participants returned to the laboratory and completed a facial emotion identification task and a clinical psychiatric interview. Results revealed that behaviorally inhibited adolescents with a lifetime history of anxiety disorder displayed a lower threshold for identifying fear relative to anger emotion expressions compared to non-anxious behaviorally inhibited adolescents and non-inhibited adolescents with or without anxiety. These findings were specific to behaviorally inhibited adolescents with a lifetime history of social anxiety disorder. Thus, adolescents with a history of both BI and anxiety, specifically social anxiety, are more likely to differ from other adolescents in their identification of fearful facial expressions. This offers further evidence that perturbations in the processing of emotional stimuli may underlie the aetiology of anxiety disorders.

Early behavioral inhibition and increased error monitoring predict later social phobia symptoms in childhood

OBJECTIVE

Behavioral inhibition (BI) is an early childhood temperament characterized by fearful responses to novelty and avoidance of social interactions. During adolescence, a subset of children with stable childhood BI develop social anxiety disorder and concurrently exhibit increased error monitoring. The current study examines whether increased error monitoring in 7-year-old, behaviorally inhibited children prospectively predicts risk for symptoms of social phobia at age 9 years.

METHOD

A total of 291 children were characterized on BI at 24 and 36 months of age. Children were seen again at 7 years of age, when they performed a Flanker task, and event-related potential (ERP) indices of response monitoring were generated. At age 9, self- and maternal-report of social phobia symptoms were obtained.

RESULTS

Children high in BI, compared to those low in BI, displayed increased error monitoring at age 7, as indexed by larger (i.e., more negative) error-related negativity (ERN) amplitudes. In addition, early BI was related to later childhood social phobia symptoms at age 9 among children with a large difference in amplitude between ERN and correct-response negativity (CRN) at age 7.

CONCLUSIONS

Heightened error monitoring predicts risk for later social phobia symptoms in children with high BI. Research assessing response monitoring in children with BI may refine our understanding of the mechanisms underlying risk for later anxiety disorders and inform prevention efforts.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Attention bias variability and symptoms of posttraumatic stress disorder

Cognitive theories implicate information-processing biases in the etiology of anxiety disorders. Results of attention-bias studies in posttraumatic stress disorder (PTSD) have been inconsistent, suggesting biases towards and away from threat. Within-subject variability of attention biases in posttraumatic patients may be a useful marker for attentional control impairment and the development of posttrauma symptoms. This study reports 2 experiments investigating threat-related attention biases, mood and anxiety symptoms, and attention-bias variability following trauma. Experiment 1 included 3 groups in a cross-sectional design: (a) PTSD, (b) trauma-exposed without PTSD, and (c) healthy controls with no trauma or Axis I diagnoses. Greater attention-bias variability was found in the PTSD group compared to the other 2 groups (η(p)2=.23); attention-bias variability was significantly and positively correlated (r = .37) with PTSD symptoms. Experiment 2 evaluated combat-exposed and nonexposed soldiers before and during deployment. Attention-bias variability did not differentiate groups before deployment, but did differentiate groups during deployment (ηp2=.16); increased variability was observed in groups with acute posttraumatic stress symptoms and acute depression symptoms only. Attention-bias variability could be a useful marker for attentional impairment related to threat cues associated with mood and anxiety symptoms after trauma exposure.

Evidence of MAOA genotype involvement in spatial ability in males

Although the monoamine oxidase-A (MAOA) gene has been linked to spatial learning and memory in animal models, convincing evidence in humans is lacking. Performance on an ecologically-valid, virtual computer-based equivalent of the Morris Water Maze task was compared between 28 healthy males with the low MAOA transcriptional activity and 41 healthy age- and IQ-matched males with the high MAOA transcriptional activity. The results revealed consistently better performance (reduced heading error, shorter path length, and reduced failed trials) for the high MAOA activity individuals relative to the low activity individuals. By comparison, groups did not differ on pre-task variables or strategic measures such as first-move latency. The results provide novel evidence of MAOA gene involvement in human spatial navigation using a virtual analogue of the Morris Water Maze task.

Fluoxetine administered to juvenile monkeys: effects on the serotonin transporter and behavior

OBJECTIVE

This study examined the long-term effects of fluoxetine administered to juvenile rhesus monkeys who, as young adults, were imaged with positron emission tomography for two serotonergic markers: serotonin transporter (SERT) and serotonin 1A (5-HT1A) receptor. An equal number of monkeys separated from their mothers at birth-an animal model of human childhood stress-were also studied.

METHOD

At birth, 32 male rhesus monkeys were randomly assigned to either maternal separation or normal rearing conditions. At age 2, half (N=8) of each group was randomly assigned to fluoxetine (3 mg/kg) or placebo for 1 year. To eliminate the confounding effects of residual drug in the brain, monkeys were scanned at least 1.5 years after drug discontinuation. Social interactions were assessed both during and after drug administration.

RESULTS

Fluoxetine persistently upregulated SERT, but not 5-HT1A receptors, in both the neocortex and the hippocampus. Whole-brain voxel-wise analysis revealed that fluoxetine had a significant effect in the lateral temporal and cingulate cortices. In contrast, neither maternal separation by itself nor the rearing-by-drug interaction was significant for either marker. Fluoxetine had no significant effect on the behavioral measures.

CONCLUSIONS

Fluoxetine administered to juvenile monkeys upregulates SERT into young adulthood. Implications regarding the efficacy or potential adverse effects of SSRIs in patients cannot be directly drawn from this study. Its purpose was to investigate effects of SSRIs on brain development in nonhuman primates using an experimental approach that randomly assigned long-term SSRI treatment or placebo.

Attention Bias Modification Treatment for children with anxiety disorders who do not respond to cognitive behavioral therapy: a case series

Evidence is emerging to support the promise of Attention Bias Modification Treatment (ABMT), a computer-based attention training program, in reducing anxiety in children. ABMT has not been tested as an adjuvant for children with anxiety disorders who do not respond to Cognitive-Behavioral Therapy (CBT). This case series presents findings from an open trial of ABMT among six children (four girls; M age = 11.2 years) who completed a CBT protocol and continued to meet diagnostic criteria for an anxiety disorder. All children completed the ABMT protocol with no canceled or missed sessions. Child self-ratings on anxiety symptoms and depressive symptoms significantly decreased from pretreatment to posttreatment, as did parent ratings on child anxiety-related impairment. Parent ratings on child anxiety and internalizing symptoms displayed non-significant decreases from pretreatment to posttreatment. These findings support the potential promise of ABMT as a feasible adjuvant treatment that reduces anxiety and impairment among child anxiety CBT nonresponders.

Neural response during explicit and implicit face processing varies developmentally in bipolar disorder

Both children and adults with bipolar disorder (BD) exhibit face emotion labeling deficits and neural circuitry dysfunction in response to emotional faces. However, few studies have compared these groups directly to distinguish effects of age and diagnosis. Such studies are important to begin to elucidate the developmental trajectory of BD and facilitate its diagnosis, prevention and treatment. This functional magnetic resonance imaging study compares 41 individuals with BD (19 children; 22 adults) and 44 age-matched healthy individuals (25 children; 19 adults) when making explicit or implicit judgments about angry or happy face morphs across a range of emotion intensity. Linear trend analyses revealed that BD patients, irrespective of age, failed to recruit the amygdala in response to increasing angry face. This finding was no longer significant when the group was restricted to euthymic youth or those without comorbid attention deficit hyperactivity disorder although this may reflect low statistical power. Deficits in subgenual anterior cingulate modulation were observed in both patient groups but were related to implicit processing for child patients and explicit processing for adult patients. Abnormalities in face emotion labeling and the circuitry mediating it may be biomarkers of BD that are present across development.

Lasting associations between early-childhood temperament and late-adolescent reward-circuitry response to peer feedback

Behavioral inhibition, a temperament identifiable in infancy, is associated with heightened withdrawal from social encounters. Prior studies raise particular interest in the striatum, which responds uniquely to monetary gains in behaviorally inhibited children followed into adolescence. Although behavioral manifestations of inhibition are expressed primarily in the social domain, it remains unclear whether observed striatal alterations to monetary incentives also extend to social contexts. In the current study, imaging data were acquired from 39 participants (17 males, 22 females; ages 16-18 years) characterized since infancy on measures of behavioral inhibition. A social evaluation task was used to assess neural response to anticipation and receipt of positive and negative feedback from novel peers, classified by participants as being of high or low interest. As with monetary rewards, striatal response patterns differed during both anticipation and receipt of social reward between behaviorally inhibited and noninhibited adolescents. The current results, when combined with prior findings, suggest that early-life temperament predicts altered striatal response in both social and nonsocial contexts and provide support for continuity between temperament measured in early childhood and neural response to social signals measured in late adolescence and early adulthood.

Screening electrocardiograms in psychiatric research: implications for physicians and healthy volunteers

AIMS

While there is controversy regarding utility of screening electrocardiograms (ECGs) in competitive athletes and children exposed to psychostimulants, there is no data on the use of screening ECGs in psychiatric research. We aimed to examine the prevalence and clinical significance of ECG abnormalities and their impact on eligibility for studies.

METHODS

We analysed 500 consecutive ECG reports from physically healthy volunteers who had a negative cardiac history, normal cardiovascular examination and no other significant medical illnesses. For the purpose of this report, all ECGs were over-read by one cardiologist.

RESULTS

The mean age of our cohort was 28.3 ± 8.0 years. A total of 112 (22.4%) ECGs were reported as abnormal (14.2%) or borderline (8.2%). These abnormalities were considered clinically insignificant in all but eight subjects (1.6%) who underwent evaluation with an echocardiogram. All echocardiograms were normal. No subject was excluded from studies. After the over-reading, no abnormalities or isolated bradycardia were present in 37 of 112 (33%) ECGs that were initially reported as abnormal or borderline, while minor abnormalities were found in 7 of 204 (3.4%) ECGs that were reported as normal.

CONCLUSIONS

Although screening ECGs did not detect significant cardiac pathology or affect eligibility for our studies, over 20% of subjects were labelled as having an abnormal or borderline ECG which was incorrect in one-third of cases. Strategies to minimise unintended consequences of screening are discussed.