An experimental analysis of chronic posttraumatic stress among adolescents

The Fear Survey Schedule (FSS), State Trait Anxiety Inventory (STAI), and the Lebanese Fear Inventory (FLI, an endemic index of war fears) were administered to a sample of Lebanese junior high school students 27 days before the Israeli invasion of 1982. Six months after the disengagement of forces, the investigator located 16 subjects who had been in West Beirut throughout the siege and 46 subjects who had evacuated to safer environs. The inventories were readministered to the subjects according to a counterbalanced regimen and no significant differences were noted between the preinvasion scores of the evacuees and nonevacuees or between the postinvasion scores of the evacuees and nonevacuees. No significant differences were observed when the aggregate FSS and STAI estimates that were recorded before and after the invasion were compared. On the other hand, the aggregate LFI scores were significantly lower after the invasion. The results are discussed from within the social learning framework of fear acquisition.     

Qualitative block design analysis in posttraumatic stress disorder

Qualitative and quantitative Block Design performance was examined in Vietnam combat veterans with PTSD diagnoses (n = 23) and Vietnam combat veterans without PTSD or other mental disorders diagnoses (n = 19). Results indicated that PTSD-diagnosed veterans committed more single block rotations than the comparison sample, and that their errors occurred more frequently in right hemispace than errors made by the comparison sample. The two groups did not differ in the number of configural errors made, errors committed in left hemispace, or in quantitative performance measures. Findings are suggestive of relative left hemisphere hypoactivation and are congruent with prior research documenting cerebral asymmetries in emotional disorders.     

Genetics of posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a prevalent anxiety disorder marked by behavioral, physiologic, and hormonal alterations. PTSD is disabling and commonly follows a chronic course. The etiology of PTSD is unknown, although exposure to a traumatic event constitutes a necessary, but not sufficient, factor. A twin study of Vietnam veterans has shown significant genetic contribution to PTSD. The fact that PTSD's underlying genotypic vulnerability is only expressed following trauma exposure limits the usefulness of family-based linkage approaches. In contrast to the other major psychiatric disorders, large studies for the search of underlying genes have not been described in PTSD to date. Complementary approaches for locating involved genes include association-based studies employing case-control or parental genotypes for transmission dysequilibrium analysis and quantitative trait loci studies in animal models. Identification of susceptibility genes will increase our understanding of traumatic stress disorders and help to elucidate their molecular basis. The current review provides an up-to-date outline of progress in the field of PTSD.     

Brain-imaging studies of posttraumatic stress disorder

Brain-imaging studies of posttraumatic stress disorder (PTSD) have rapidly increased in recent years. Structural studies have identified potential smaller volumes of the hippocampus of traumatized and/or PTSD subjects. Functional activation studies have implicated hyperactive or altered functioning of brain regions, such as the amygdala and the insula, and a failure to engage emotional regulatory structures, such as the medial prefrontal and anterior cingulate cortex. Recent neurochemical investigations have suggested that neuromodulatory systems (eg, gamma-aminobutyric acid, micro-opioid) may underlie these aberrant brain activation patterns. This article reviews the literature on structural, functional, and neurochemical brain-imaging studies of PTSD.     

An experimental analysis of hypochondriasis

Hypochondriasis (HC) involves preoccupation with fears of having a serious medical illness based on the misinterpretation of benign bodily perturbations. Individuals with HC also perform behaviors such as checking and reassurance-seeking presumably to reduce health-related fears. Experimental behavioral analyses of HC symptoms, however, are lacking. In the present study, 27 patients with HC were exposed to personally relevant health-related stimuli under one of two conditions: (a) subsequently performing safety-seeking behaviors (e.g., checking) (n=14) or (b) subsequently being instructed not to perform such behaviors (n=13). In both groups, subjective anxiety and urges to perform safety behaviors were monitored for 1h. Results indicated that exposure to the personally relevant health trigger provoked anxiety and urges to perform safety behaviors. For patients who performed such behaviors, these feelings were reduced. For patients who did not, a more gradual reduction of anxiety and urges was observed. Findings are discussed in terms of the conceptualization and treatment of HC behavior, and are relevant to HC's possible relationship to panic and obsessive-compulsive disorder.     

Fear conditioning in posttraumatic stress disorder: evidence for delayed extinction of autonomic, experiential, and behavioural responses

Aversive conditioning has been proposed as an important factor involved in the etiology of posttraumatic stress disorder (PTSD). However, it is not yet fully understood exactly which learning mechanisms are characteristic for PTSD. PTSD patients (n=36), and healthy individuals with and without trauma exposure (TE group, n=21; nTE group, n=34), underwent a differential fear conditioning experiment consisting of habituation, acquisition, and extinction phases. An electrical stimulus served as the unconditioned stimulus (US), and two neutral pictures as conditioned stimuli (CS+, paired; CS-, unpaired). Conditioned responses were quantified by skin conductance responses (SCRs), subjective ratings of CS valence and US-expectancy, and a behavioural test. In contrast to the nTE group, PTSD patients showed delayed extinction of SCRs to the CS+. Online ratings of valence and US-expectancy as well as the behavioural test confirmed this pattern. These findings point to a deficit in extinction learning and highlight the role of affective valence appraisals and cognitive biases in PTSD. In addition, there was some evidence that a subgroup of PTSD patients had difficulties in learning the CS-US contingency, thereby providing preliminary evidence of reduced discrimination learning.     

Gender differences in posttraumatic stress disorder

One of the most consistent findings in the epidemiology of posttraumatic stress disorder (PTSD) is the higher risk of this disorder in women. Explanations reviewed within a psychobiological model of PTSD suggest that women's higher PTSD risk may be due to the type of trauma they experience, their younger age at the time of trauma exposure, their stronger perceptions of threat and loss of control, higher levels of peri-traumatic dissociation, insufficient social support resources, and greater use of alcohol to manage trauma-related symptoms like intrusive memories and dissociation, as well as gender-specific acute psychobiological reactions to trauma. This review demonstrates the need for additional research of the gender differences in posttraumatic stress. Recommendations are made for clinical practice.     

Emotional processing in posttraumatic stress disorder

The emotional deficits associated with posttraumatic stress disorder (PTSD) are the least understood and the most understudied aspect of the syndrome. In this study, the connection was evaluated between trauma-context reactivity and subsequent emotional deficits in PTSD. Combat veterans with PTSD and well-adjusted veteran control participants were exposed to reminders of combat, after which their emotional behavior was assessed in response to a series of emotionally evocative images. Under the neutral condition, both groups exhibited emotional behavior modulated by stimulus valence. Partially consistent with the conceptual model described by B. Litz (1992), the PTSD group exhibited suppressed expressive-motor responses to positively valenced images, in comparison with the control group, only after being exposed to a trauma-related prime. Contrary to expectations, the PTSD group showed no augmentation of emotional response to negatively valenced cues after being exposed to trauma reminders. However, the PTSD group responded to all images, in both prime conditions, with higher heart rate reactivity, suggesting an automatic preparation for demand or threat in any uncertain emotional context. Possible causes and consequences of these results are discussed.     

Counterfactual thinking and posttraumatic stress reactions

Preoccupation with alternative outcomes (counterfactual thinking) is a central component of the ruminations of trauma victims. The questions investigated were whether such thinking should be distinguished from general rumination and whether elements of counterfactual thinking might relate to the process of adjustment. A sample of assault victims was interviewed. They completed a battery of self-report scales and thought-listing procedures. Frequency of counterfactual thinking was closely associated with continuing levels of posttraumatic distress. However, high availability of counterfactuals (as indexed by verbal fluency) was related to potentially adaptive outcomes, such as the generation of behavioral plans. In addition, as expected, levels of different aspects of counterfactual thinking were moderated by metacognitive control strategies as a function of time since the trauma.     

Psychotic symptoms in posttraumatic stress disorder

Recent data suggest that the presence of psychotic symptoms in patients suffering from posttraumatic stress disorder (PTSD) may represent an underrecognized and unique subtype of PTSD. Among combat veterans with PTSD, 30% to 40% report auditory or visual hallucinations and/or delusions. The presence of psychotic symptoms in PTSD is associated with a more severe level of psychopathology, similar to that of chronic schizophrenia. In this review, the differential diagnosis of psychotic symptoms in PTSD is discussed, including possible comorbid schizophrenia, psychotic depression, substance-induced psychosis, and personality disorder. A recent biologic study supporting the existence of a unique subtype of PTSD with psychotic features is also addressed, as are the similarities between PTSD with psychotic features and psychotic depression disorder. Finally, data on the treatment implications of psychotic symptoms in PTSD are presented. The intriguing recent findings on psychotic symptoms in PTSD need further investigation in noncombat-related PTSD populations before findings can be generalized to all individuals with PTSD.     

A cognitive model of posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a common reaction to traumatic events. Many people recover in the ensuing months, but in a significant subgroup the symptoms persist, often for years. A cognitive model of persistence of PTSD is proposed. It is suggested that PTSD becomes persistent when individuals process the trauma in a way that leads to a sense of serious, current threat. The sense of threat arises as a consequence of: (1) excessively negative appraisals of the trauma and/or its sequelae and (2) a disturbance of autobiographical memory characterised by poor elaboration and contextualization, strong associative memory and strong perceptual priming. Change in the negative appraisals and the trauma memory are prevented by a series of problematic behavioural and cognitive strategies. The model is consistent with the main clinical features of PTSD, helps explain several apparently puzzling phenomena and provides a framework for treatment by identifying three key targets for change. Recent studies have provided preliminary support for several aspects of the model.     

An experimental analysis of anti-litter procedures

This study evaluates the differential effectiveness of six different anti-litter procedures in two neighborhood theaters. The procedures used to encourage individuals in attendance to pick up litter and deposit it properly included: providing litterbags, providing litterbags with instructions to use them, providing extra trash cans, showing a special anti-litter film before the feature film, and providing incentives for the appropriate deposit of litter. In both theaters, the incentive procedures resulted in the removal of over 90% of all litter by the children in attendance, a figure far above that achieved by the other procedures investigated.     

An experimental analysis of social traps

Social traps, such as the overgrazing of pasturelands, overpopulation, and the extinction of species, are situations where individuals in a group respond for their own advantage in a manner damaging to the group. A laboratory analog was devised to simulate conditions that produce social traps. The traps were constructed by superimposing schedules of reinforcement. Single responses were followed by multiple consequences which were opposite in valence, with the negative consequence delayed. Subjects in groups of three could respond individually for points that applied toward class credit. Each ten presses of a button added one point to the subject's total and subtracted one point from a common pool. The pool was replenished with points at fixed rates. If subjects responded for points faster than the replenishment rates, the pool would empty and the experiment would terminate before subjects could accumulate maximum credit. In addition, the maximum pool size and the ability to communicate were varied. Main effects were found for both, which indicated the least effective resource management occurred when the pool was small and no communication allowed. An analysis of cumulative records showed differing response patterns across conditions.     

An experimental analysis of body checking

The relationship between repeated body checking and its impact on body size estimation and body dissatisfaction is of interest for two reasons. First, it has importance in theoretical accounts of the maintenance of eating disorders and, second, body checking is targeted in cognitive-behavioural treatment. The aim of this study was to determine the impact of manipulating body checking on body size estimation and body dissatisfaction. Sixty women were randomly assigned either to repeatedly scrutinize their bodies in a critical way in the mirror ("high body checking") or to refrain from body checking but to examine the whole of their bodies in a neutral way ("low body checking"). Body dissatisfaction, feelings of fatness and the strength of a particular self-critical thought increased immediately after the manipulation among those in the high body checking condition. Feelings of fatness decreased among those in the low body checking condition. These changes were short-lived. The manipulation did not effect estimations of body size or the discrepancy between estimations of body size and desired body size. The implications of these findings for understanding the influence of body checking on the maintenance of body dissatisfaction are considered.