Matthew O. Kimble

Exposure-based cognitive-behavioral treatment of PTSD in adults with schizophrenia or schizoaffective disorder : A pilot study

In an open trial design, adults (n=20) with posttraumatic stress disorder (PTSD) and either schizophrenia or schizoaffective disorder were treated via an 11-week cognitive-behavioral intervention for PTSD that consisted of education, anxiety management therapy, social skills training, and exposure therapy, provided at community mental health centers. Results offer preliminary hope for effective treatment of PTSD among adults with schizophrenia or schizoaffective disorder, especially among treatment completers (n=13). Data showed significant PTSD symptom improvement, maintained at 3-month follow-up. Further, 12 of 13 completers no longer met criteria for PTSD or were considered treatment responders. Clinical outcomes for other targeted domains (e.g., anger, general mental health) also improved and were maintained at 3-month follow-up. Participants evidenced high treatment satisfaction, with no adverse events. Significant improvements were not noted on depression, general anxiety, or physical health status. Future directions include the need for randomized controlled trials and dissemination efforts.

Eye tracking and visual attention to threating stimuli in veterans of the Iraq war

Theoretical and clinical characterizations of attention in PTSD acknowledge the possibility for both hypervigilance and avoidance of trauma-relevant stimuli. This study used eye tracking technology to investigate visual orientation and attention to traumatic and neutral stimuli in nineteen veterans of the Iraq war. Veterans saw slides in which half the screen had a negatively valenced image and half had a neutral image. Negatively valenced stimuli were further divided into stimuli that varied in trauma relevance (either Iraq war or civilian motor vehicle accidents). Veterans reporting relatively higher levels of PSTD symptoms had larger pupils to all negatively valenced pictures and spent more time looking at them than did veterans lower in PTSD symptoms. Veterans higher in PTSD symptoms also showed a trend towards looking first at Iraq images. The findings suggest that post-traumatic pathology is associated with vigilance rather than avoidance when visually processing negatively valenced and trauma-relevant stimuli.

Peritraumatic dissociation and physiological response to trauma-relevant stimuli in Vietnam combat veterans with posttraumatic stress disorder

A recent study found that female rape victims with acute posttraumatic stress disorder (PTSD) who received a high score on the Peritraumatic Dissociative Experiences Questionnaire exhibited suppression of physiological responses during exposure to trauma-related stimuli. The goal of our present study was to test whether the same relationship holds true for male Vietnam combat veterans with chronic PTSD, using secondary analyses applied to data derived from a Veteran’s Affairs Cooperative Study. Vietnam combat veterans (N = 1238) completed measures to establish combat-related PTSD diagnostic status, extent of PTSD-related symptomatic distress, and presence of dissociative symptoms during their most stressful combat-related experiences. Extreme subgroups of veterans with current PTSD were classified as either low dissociators (N = 118) or high dissociators (N = 256) based on an abbreviated version of the Peritraumatic Dissociative Experiences Questionnaire. Dependent variables reflected subjective distress along with heart rate, skin conductance, electromyographic, and blood pressure data when responding to neutral and trauma-related audiovisual and imagery presentations. Veterans in the current PTSD group had significantly higher dissociation scores than did veterans in the lifetime and never PTSD groups. Among veterans with current PTSD, high dissociators reported greater PTSD-related symptomatic distress than did low dissociators, but the groups did not differ with respect to physiological reactivity to the trauma-related laboratory presentations. Our results replicate the previously reported relationship between peritraumatic dissociation and PTSD status in Vietnam combat veterans. However, we found no association between peritraumatic dissociation and the extent of physiological responding to trauma-relevant cues in male veterans with chronic combat-related PTSD.

Does the modified Stroop effect exist in PTSD? Evidence from dissertation abstracts and the peer reviewed literature.

The modified Stroop effect (MSE), in which participants show delayed colour naming to trauma-specific words, is one of the most widely cited findings in the literature pertaining to cognitive bias in posttraumatic stress disorder (PTSD). The current study used a novel approach (Dissertation Abstract Review; DAR) to review the presence of the MSE in dissertation abstracts. A review of dissertations that used the modified Stroop task in a PTSD sample revealed that only 8% of the studies found delayed reaction times to trauma-specific words in participants with PTSD. The most common finding (75%) was for no PTSD-specific effects in colour naming trauma-relevant words. This ratio is significantly lower than ratios found in the peer reviewed literature, but even in the peer reviewed literature only 44% of controlled studies found the modified Stroop effect. These data suggest that a reevaluation of the MSE in PTSD is warranted.

Cognitive-behavioral treatment for PTSD among people with severe mental illness: a proposed treatment model.

The lifetime prevalence of posttraumatic stress disorder (PTSD) is about 8%–14% in the general population, and trauma victimization (51%–98%) and PTSD (up to 42%) are even more prevalent among persons treated within public-sector mental health clinics. Despite this, individuals with PTSD and severe mental illness (SMI) who are treated within the public sector tend to receive inadequate mental health services. In addition, treatments for PTSD for this population remain undeveloped, with virtually no available empirical treatment outcome data to guide clinicians. We propose a model for a comprehensive, multicomponent cognitive-behavioral treatment program for this target population that includes elements of consumer education, anxiety management training, social skills training, exposure therapy, “homework” assignments, and long-term follow-up care. Special considerations for public-sector consumers with PTSD and SMI are addressed, as are directions for future research.

Sentence completion test in combat veterans with and without PTSD: preliminary findings

This study used a sentence completion task to assess semantic choice in combat veterans. Twenty-eight combat veterans with (n=14) and without (n=14) posttraumatic stress disorder (PTSD) filled in the final word for 33 incomplete sentences after receiving a combat prime. The veterans with PTSD completed sentences with significantly more trauma-relevant final words than those without PTSD. Findings are interpreted with respect to current language models and information-processing theories of PTSD.

The impact of hypervigilance: evidence for a forward feedback loop.

A number of prominent theories suggest that hypervigilance and attentional bias play a central role in anxiety disorders and PTSD. It is argued that hypervigilance may focus attention on potential threats and precipitate or maintain a forward feedback loop in which anxiety is increased. While there is considerable data to suggest that attentional bias exists, there is little evidence to suggest that it plays this proposed but critical role. This study investigated how manipulating hypervigilance would impact the forward feedback loop via self-reported anxiety, visual scanning, and pupil size. Seventy-one participants were assigned to either a hypervigilant, pleasant, or control condition while looking at a series of neutral pictures. Those in the hypervigilant condition had significantly more fixations than those in the other two groups. These fixations were more spread out and covered a greater percentage of the ambiguous scene. Pupil size was also significantly larger in the hypervigilant condition relative to the control condition. Thus the study provided support for the role of hypervigilance in increasing visual scanning and arousal even to neutral stimuli and even when there is no change in self-reported anxiety. Implications for the role this may play in perpetuating a forward feedback loop are discussed.

Contributors to Hypervigilance in a Military and Civilian Sample

Hypervigilance toward ambiguous or threatening stimuli is a prominent feature in many trauma survivors including active and returning soldiers. This study set out to investigate the factors that contribute to hypervigilance in a mixed sample. One hundred forty-five individuals, 50 of whom were war zone veterans, filled out a series of questionnaires including the Hypervigilance Questionnaire (HVQ; Kimble, Fleming, & Bennion, 2009). Other participants included military cadets, college undergraduates, and a traumatized community sample. In this sample, a history of military deployment and posttraumatic stress disorder symptoms independently predicted hypervigilance. The findings suggest that deployment to a war zone, in and of itself, can lead to hypervigilant behavior. Therefore, characterizing hypervigilance as pathological in a veteran sample must be done so with caution.

Sexual Assault Victimization Among Female Undergraduates During Study Abroad A Single Campus Survey Study

Almost all research on sexual assault victimization among undergraduate university students pertains to incidents that occur on domestic college and university campuses. The purpose of the present study was to investigate the prevalence of sexual assault victimization and related factors among undergraduates in the context of study-abroad programs. Two hundred eight female students (52% response rate) from a small university in the northeastern United States who had recently studied abroad responded to an online survey containing measures of sexual assault, posttraumatic stress responses (PSR), and alcohol consumption. Almost 19% of the respondents indicated one or more types of sexual assault victimization. Approximately 17% reported non-consensual sexual touching, 7% attempted rape, 4% rape, with 9% reporting attempted rape or rape. As in domestic studies, victimization in this sample was related positively to alcohol consumption and PSR. Use of force was the most frequently reported perpetrator tactic. In sum, the high rates of sexual assault victimization reported by this sample during study abroad replicate previous findings. This context requires further attention from sexual assault researchers, especially given the increasing numbers of university students engaging in study abroad, and from campus support personnel who may be unaware of the likelihood of assault in this context.

Decisions to shoot in a weapon identification task: The influence of cultural stereotypes and perceived threat on false positive errors

Abstract The decision to shoot a gun engages executive control processes that can be biased by cultural stereotypes and perceived threat. The neural locus of the decision to shoot is likely to be found in the anterior cingulate cortex (ACC), where cognition and affect converge. Male military cadets at Norwich University (N=37) performed a weapon identification task in which they made rapid decisions to shoot when images of guns appeared briefly on a computer screen. Reaction times, error rates, and electroencephalogram (EEG) activity were recorded. Cadets reacted more quickly and accurately when guns were primed by images of Middle-Eastern males wearing traditional clothing. However, cadets also made more false positive errors when tools were primed by these images. Error-related negativity (ERN) was measured for each response. Deeper ERNs were found in the medial-frontal cortex following false positive responses. Cadets who made fewer errors also produced deeper ERNs, indicating stronger executive control. Pupil size was used to measure autonomic arousal related to perceived threat. Images of Middle-Eastern males in traditional clothing produced larger pupil sizes. An image of Osama bin Laden induced the largest pupil size, as would be predicted for the exemplar of Middle East terrorism. Cadets who showed greater increases in pupil size also made more false positive errors. Regression analyses were performed to evaluate predictions based on current models of perceived threat, stereotype activation, and cognitive control. Measures of pupil size (perceived threat) and ERN (cognitive control) explained significant proportions of the variance in false positive errors to Middle-Eastern males in traditional clothing, while measures of reaction time, signal detection response bias, and stimulus discriminability explained most of the remaining variance.