Michael Schönenberg

Ketamine aggravates symptoms of acute stress disorder in a naturalistic sample of accident victims.

The glutamatergic N-methyl-D-aspartate receptor antagonist ketamine produces transient dissociative states and alters cognitive functioning in healthy humans, thus resembling the core symptoms of acute and chronic post-traumatic stress disorder (PTSD). First evidence exists that the common use of the analgesic and sedative properties of ketamine during emergency care correlates with sustained symptoms of PTSD in accident victims. The aim of the present study was to examine whether ketamine administration after moderate accidental trauma modulates dissociation and other symptoms of acute stress disorder (ASD) in the direct aftermath of the event. Accident victims were screened within the third day after admission to hospital for symptoms of ASD (Peritraumatic Dissociative Experiences Questionnaire, ASD Scale) and prior stressful life events (Traumatic Life Events Questionnaire). Subjects had received a single or fractionated dose of either racemic ketamine (n = 13), opioids (n = 24) or non-opioid analgesics (n = 13) during initial emergency treatment. There were no significant differences between medication groups in demographic and clinical characteristics such as injury severity or prior traumatization. With respect to ASD symptomatology three days post-event there were significant associations between ketamine analgosedation and increased symptoms of dissociation, reexperiencing, hyperarousal and avoidance relative to the comparison groups.Growing evidence exists that ketamine might modulate or aggravate early post-traumatic stress reactions when given in the acute trauma phase, which in turn might contribute to long-lasting symptomatology.

Effects of peritraumatic ketamine medication on early and sustained posttraumatic stress symptoms in moderately injured accident victims

RationaleKetamine, an N-methyl-d-aspartate receptor antagonist, produces transient dissociative and psychotic states in healthy humans that resemble symptoms shown by subjects with acute and chronic posttraumatic stress disorder (PTSD). Since ketamine is widely used as an analgesic and sedative in emergency care, it might be one factor triggering, modulating, or exacerbating PTSD in accident victims when given in the acute trauma phase.ObjectivesThe purpose of the present study was to determine whether the peritraumatic administration of ketamine affects acute and sustained PTSD symptoms in accident victims.MethodsA sample of 56 moderately injured accident victims was screened retrospectively for acute (Peritraumatic Dissociative Experiences Questionnaire; Acute Stress Disorder Scale) and for current PTSD symptoms (Impact of Event Scale) approximately 1 year postaccident. All subjects had received a single or fractionated dose of either racemic ketamine (n=17), (S)-ketamine (n=12), or opioids (n=27) during emergency ambulance transportation.ResultsRetrospectively assessed acute symptomatology was strongly increased in (S)-ketamine subjects in terms of dissociation, reexperiencing, and avoidance, and slightly heightened in racemic ketamines. Current PTSD symptoms were substantially elevated in (S)-ketamine subjects, while there was no difference observed between opioids and racemic ketamines. Medication groups did not differ in regard to demographic variables, previous or postaccidental traumatic events, time between accident and investigation, and injury severity.ConclusionsThe data provide first evidence for a modulating effect of a single-dose ketamine on the severity and duration of posttraumatic stress symptoms in accident victims.

Investigation of the hostile attribution bias toward ambiguous facial cues in antisocial violent offenders

Abstract Aggressive individuals exhibit a strong tendency to attribute hostile intent to the behavior of others, which may lead to provocation and aggravation of socially inappropriate reactions. Limited research has investigated the hostile attribution bias in the perception of facial affect. This study examined a hostile response bias to emotionally ambiguous faces in a population of 55 incarcerated antisocial violent offenders as compared to matched control subjects. Results suggest that aggression is associated with a strong preference to interpret ambiguous stimuli containing proportions of an angry expression as hostile, while there was no evidence for a generally biased interpretation of distress cues under conditions of uncertainty. Thus, the tendency to misinterpret nonverbal cues in social interactions may at least partly underlie aggressive–impulsive behavior in susceptible individuals.

Addressing perceptual insensitivity to facial affect in violent offenders: first evidence for the efficacy of a novel implicit training approach.

BACKGROUND Although impaired recognition of affective facial expressions has been conclusively linked to antisocial behavior, little is known about the modifiability of this deficit. This study investigated whether and under which circumstances the proposed perceptual insensitivity can be addressed with a brief implicit training approach. METHOD Facial affect recognition was assessed with an animated morph task, in which the participants (44 male incarcerated violent offenders and 43 matched controls) identified the onset of emotional expressions in animated morph clips that gradually changed from neutral to one of the six basic emotions. Half of the offenders were then implicitly trained to direct attention to salient face regions (attention training, AT) using a modified dot-probe task. The other half underwent the same protocol but the intensity level of the presented expressions was additionally manipulated over the course of training sessions (sensitivity to emotional expressions training, SEE training). Subsequently, participants were reassessed with the animated morph task. RESULTS Facial affect recognition was significantly impaired in violent offenders as compared with controls. Further, our results indicate that only the SEE training group exhibited a pronounced improvement in emotion recognition. CONCLUSIONS We demonstrated for the first time that perceptual insensitivity to facial affect can be addressed by an implicit training that directs attention to salient regions of a face and gradually decreases the intensity of the emotional expression. Future studies should focus on the potential of this intervention to effectively increase empathy and inhibit violent behavior in antisocial individuals.

Is impaired set-shifting a feature of ''pure'' anorexia nervosa? Investigating the role of depression in set-shifting ability in anorexia nervosa and unipolar depression

Impaired set-shifting has been reported in patients with anorexia nervosa (AN) and in patients with affective disorders, including major depression. Due to the prevalent comorbidity of major depression in AN, this study aimed to examine the role of depression in set-shifting ability. Fifteen patients with AN without a current comorbid depression, 20 patients with unipolar depression (UD) and 35 healthy control participants were assessed using the Trail Making Test (TMT), the Wisconsin Card Sorting Test (WCST) and a Parametric Go/No-Go Test (PGNG). Set-shifting ability was intact in patients with AN without a comorbid depression. However, patients with UD performed significantly poorer in all three tasks compared to AN patients and in the TMT compared to healthy control participants. In both patient groups, set-shifting ability was moderately negatively correlated with severity of depressive symptoms, but was unrelated to BMI and severity of eating disorder symptoms in AN patients. Our results suggest a pivotal role of comorbidity for neuropsychological functioning in AN. Impairments of set-shifting ability in AN patients may have been overrated and may partly be due to comorbid depressive disorders in investigated patients.

Frontal alpha-asymmetry in adults with attention deficit hyperactivity disorder: Replication and specification

Recent findings suggest that adults suffering from attention deficit hyperactivity disorder (ADHD) display an atypical pattern of hemispheric asymmetry, assessed through the alpha band in resting-state electroencephalogram. In the context of the approach-withdrawal model of hemispheric asymmetry, this pattern has been identified as a correlate of approach-related behavior, particularly in anterior brain regions. The current study sought to replicate previous findings on alpha asymmetry in ADHD, and to specify them based on the assumption that ADHD represents a disorder of excessive approach tendencies. A group of ADHD patients (n=19) was compared to a group of healthy controls (n=19) on measures of alpha asymmetry and aggression, an approach-related trait. Observed region-specific group differences in alpha asymmetry approximated assumptions of the approach-withdrawal model. In addition ADHD subjects displayed elevated levels of a subcomponent of aggression. These results provide support for a conceptualization of ADHD as a disorder of excessive approach tendencies.

IMPAIRED IDENTIFICATION OF THREAT-RELATED SOCIAL INFORMATION IN MALE DELINQUENTS WITH ANTISOCIAL PERSONALITY DISORDER

The present study aimed to investigate the identification of threat-related facial expressions in aggressive individuals with antisocial personality disorder (ASPD). Thirty-two male delinquents and matched healthy controls were presented with a series of animated morph-clips that gradually display the onset and development of angry, fearful, and happy facial expressions. ASPD subjects required significantly higher levels of emotional intensity to correctly identify the onset of an angry facial expression as compared to control participants. In contrast, recognition of fearful and happy expressions was unimpaired. These findings suggest a specific deficit in the identification of hostile facial expressions in ASPD populations.

Frontal brain asymmetry in adult attention-deficit/hyperactivity disorder (ADHD): Extending the motivational dysfunction hypothesis

OBJECTIVE Attention-deficit/hyperactivity disorder (ADHD) involves motivational dysfunction, characterized by excessive behavioral approach tendencies. Frontal brain asymmetry in the alpha band (8-13 Hz) in resting-state electroencephalogram (EEG) represents a neural correlate of global motivational tendencies, and abnormal asymmetry, indicating elevated approach motivation, was observed in pediatric and adult patients. To date, the relation between ADHD symptoms, depression and alpha asymmetry, its temporal metric properties and putative gender-specificity remain to be explored. METHODS Adult ADHD patients (n=52) participated in two resting-state EEG recordings, two weeks apart. Asymmetry measures were aggregated across recordings to increase trait specificity. Putative region-specific associations between asymmetry, ADHD symptoms and depression, its gender-specificity and test-retest reliability were examined. RESULTS ADHD symptoms were associated with approach-related asymmetry (stronger relative right-frontal alpha power). Approach-related asymmetry was pronounced in females, and also associated with depression. The latter association was mediated by ADHD symptoms. Test-retest reliability was sufficient. CONCLUSIONS The association between reliably assessable alpha asymmetry and ADHD symptoms supports the motivational dysfunction hypothesis. ADHD symptoms mediating an atypical association between asymmetry and depression may be attributed to depression arising secondary to ADHD. Gender-specific findings require replication. SIGNIFICANCE Frontal alpha asymmetry may represent a new reliable marker of ADHD symptoms.

Threat processing in generalized social phobia: An investigation of interpretation biases in ambiguous facial affect

Facial affect is one of the most important information sources during the course of social interactions, but it is susceptible to distortion due to the complex and dynamic nature. Socially anxious individuals have been shown to exhibit alterations in the processing of social information, such as an attentional and interpretative bias toward threatening information. This may be one of the key factors contributing to the development and maintenance of anxious psychopathology. The aim of the current study was to investigate whether a threat-related interpretation bias is evident for ambiguous facial stimuli in a population of individuals with a generalized Social Anxiety Disorder (gSAD) as compared to healthy controls. Participants judged ambiguous happy/fearful, angry/fearful and angry/happy blends varying in intensity and rated the predominant affective expression. The results obtained in this study do not indicate that gSAD is associated with a biased interpretation of ambiguous facial affect.

Empathy promotes altruistic behavior in economic interactions.

What are the determinants of altruism? While economists assume that altruism is mainly driven by fairness norms, social psychologists consider empathy to be a key motivator for altruistic behavior. To unite these two theories, we conducted an experiment in which we compared behavior in a standard economic game that assesses altruism (the so-called Dictator Game) with a Dictator Game in which participants’ behavioral choices were preceded either by an empathy induction or by a control condition without empathy induction. The results of this within-subject manipulation show that the empathy induction substantially increased altruistic behavior. Moreover, the increase in experienced empathy predicted over 40% of the increase in sharing behavior. These data extend standard economic theories that altruism is based on fairness considerations, by showing that empathic feelings can be a key motivator for altruistic behavior in economic interactions.