Danny G. Kaloupek

Neural correlates of exposure to traumatic pictures and sound in Vietnam combat veterans with and without posttraumatic stress disorder: a positron emission tomography study.

BACKGROUND Patients with posttraumatic stress disorder (PTSD) show a reliable increase in PTSD symptoms and physiological reactivity following exposure to traumatic pictures and sounds. In this study neural correlates of exposure to traumatic pictures and sounds were measured in PTSD. METHODS Positron emission tomography and H2[15O] were used to measure cerebral blood flow during exposure to combat-related and neutral pictures and sounds in Vietnam combat veterans with and without PTSD. RESULTS Exposure to traumatic material in PTSD (but not non-PTSD) subjects resulted in a decrease in blood flow in medial prefrontal cortex (area 25), an area postulated to play a role in emotion through inhibition of amygdala responsiveness. Non-PTSD subjects activated anterior cingulate (area 24) to a greater degree than PTSD patients. There were also differences in cerebral blood flow response in areas involved in memory and visuospatial processing (and by extension response to threat), including posterior cingulate (area 23), precentral (motor) and inferior parietal cortex, and lingual gyrus. There was a pattern of increases in PTSD and decreases in non-PTSD subjects in these areas. CONCLUSIONS The findings suggest that functional alternations in specific cortical and subcortical brain areas involved in memory, visuospatial processing, and emotion underlie the symptoms of patients with PTSD.

Utility of Psychophysiological Measurement in the Diagnosis of Posttraumatic Stress Disorder: Results From a Department of Veterans Affairs Cooperative Study

This multisite study tested the ability of psychophysiological responding to predict posttraumatic stress disorder (PTSD) diagnosis (current, lifetime, or never) in a large sample of male Vietnam veterans. Predictor variables for a logistic regression equation were drawn from a challenge task involving scenes of combat. The equation was tested and cross-validated demonstrating correct classification of approximately 2/3 of the current and never PTSD participants. Results replicate the finding of heightened psychophysiological responding to trauma-related cues by individuals with current PTSD, as well as differences in a variety of other domains between groups with and without the disorder. Follow-up analyses indicate that veterans with current PTSD who do not react physiologically to the challenge task manifest less reexperiencing symptoms, depression, and guilt. Discussion addresses the value of psychophysiological measures for assessment of PTSD.

A Meta-Analytic Examination of Basal Cardiovascular Activity in Posttraumatic Stress Disorder

Objective The objective of this meta-analytic study was to determine whether individuals with posttraumatic stress disorder (PTSD) have higher levels of basal cardiovascular activity relative to comparable groups of individuals without PTSD. Methods Meta-analytic data methods were applied to 34 studies that gathered indicators of basal cardiovascular activity including: heart rate (HR), systolic blood pressure, and diastolic blood pressure on subjects diagnosed with PTSD and two types of comparison groups. In total, cardiovascular measures were analyzed for 2670 subjects across all studies. Results Results indicate that individuals with a current PTSD diagnosis have higher resting HR relative to both trauma-exposed individuals without a PTSD diagnosis and non–trauma-exposed individuals. The results also suggest that PTSD is associated with elevations in blood pressure; however, the effect sizes were smaller in magnitude than those obtained for heart rate. A subset analysis revealed that the effect sizes for comparisons on basal HR were greatest in studies with the most chronic PTSD samples. Conclusion The meta-analysis supports previous qualitative reviews, finding a positive association between PTSD and basal cardiovascular activity. The discussion addresses possible mechanisms of action and the health-related implications of these findings.

Decreased Anterior Cingulate Volume in Combat-Related PTSD

BACKGROUND Neuroanatomical data point to functional relationships between the anterior cingulate cortex (ACC) and subcortical centers regulating fear, in particular, the amygdala. Functional brain imaging has disclosed divergent patterns of ACC activation in persons with posttraumatic stress disorder (PTSD). In addition, two preliminary structural imaging studies have found evidence of smaller ACC volume in PTSD. We explored associations between PTSD and ACC volume in a relatively large sample of adult combat veterans in which PTSD, lifetime alcohol abuse/dependence, and Vietnam versus Gulf War service were crossed. METHODS Subjects were US military combat veterans of the Vietnam and Gulf Wars recruited from two metropolitan areas served by allied Department of Veterans Affairs PTSD treatment/research centers. Anterior cingulate cortex volume was analyzed as a function of grouping factors with and without adjustment for body size. RESULTS Posttraumatic stress disorder was associated with smaller anterior cingulate cortex volume. This effect persisted in subjects without histories of alcoholism, did not interact with cohort effects, and was not modified by adjustment for body size. CONCLUSIONS Anterior cingulate cortex volume is substantially smaller in association with combat-related PTSD, a finding broadly consistent with cingulate hypofunctionality in that disorder.

Posttraumatic Stress Disorder Symptoms, Physiological Reactivity, Alcohol Problems, and Aggression Among Military Veterans

This study examined the association between posttraumatic stress disorder (PTSD) symptomatology and aggressive behavior among a sample of male Vietnam veterans (N = 1,328). Results indicated that the hyperarousal PTSD symptom cluster evidenced the strongest positive association with aggression at the bivariate level when compared with the other PTSD symptom clusters. When the PTSD symptom clusters were examined together as predictors, hyperarousal symptoms evidenced a significant positive relationship with aggression, and avoidance/numbing symptoms were negatively associated with aggression. Examination of potential mediators indicated that hyperarousal symptoms were directly associated with aggression and indirectly related to aggression via alcohol problems. Reexperiencing symptoms were associated with aggression only indirectly and through their positive association with physiological reactivity and negative association with alcohol problems. Study results highlight the complexity of the relationship between PTSD symptoms and aggression, and suggest possible mechanisms explaining this association.

Externalizing and Internalizing Subtypes of Combat-Related PTSD: A Replication and Extension Using the PSY-5 Scales

This study replicated and extended prior findings of internalizing and externalizing subtypes of posttraumatic response (M. W. Miller, J. L. Greif, & A. A. Smith, 2003). Cluster analyses of the Minnesota Multiphasic Personality Inventory--2 Personality Psychopathology--Five (MMPI-2 PSY-5; A. R. Harkness, J. L. McNulty, Y. S. Ben-Porath, 1995) profiles obtained from 736 veterans with posttraumatic stress disorder (PTSD) partitioned the sample into a low pathology cluster defined by personality scores in the normal range, an externalizing cluster characterized by low constraint and high negative emotionality, and an internalizing cluster with high negative emotionality and low positive emotionality. Externalizers showed the highest rates of alcohol-related and antisocial personality disorders; internalizers, the highest rates of panic and major depressive disorder. These findings support the development of a personality-based typology of posttraumatic response designed to account for heterogeneity in the expression of PTSD and associated psychopathology.

Comorbid psychiatric disorders in PTSD. Implications for research.

It is clear from the existing data that PTSD often occurs in the context of other major psychological conditions. Evidence to support this comes from clinical studies, epidemiological studies, and studies of PTSD among substance abusers. Clearly, probably several different subgroups of PTSD patients exist including those who had psychological or behavioral problems before exposure to traumatic events (e.g., substance abuse), those who developed other problems concurrent with exposure to the traumatic events, and those who developed problems secondary to the development of PTSD, perhaps in efforts to cope with the intensely debilitating symptoms of PTSD. With this knowledge, research on PTSD must begin to contend with the comorbidity issue in systematic ways. The use of comparison groups that are carefully selected is one key way in which conclusions about PTSD can be most conservatively drawn. The use of statistical procedures to control for difference in levels of comorbidity is another responsible way in which to approach the problem. Finally, efforts to employ global measures of functioning such as the Global Assessment of Functioning to equate subjects within a study on minimally this characteristic may be the most economical method for trying to rule out the role of comorbidity and severity of condition in conclusions drawn in research studies. All these solutions presuppose the careful measurement of comorbidity in studies of PTSD, a recommendation that requires serious consideration for researchers operating in this field.

Posttraumatic Stress Disorder and the Use of Health Services

Objective Prior research has demonstrated increased use of medical services among persons with anxiety and depression. This investigation examined the possible association of posttraumatic stress disorder (PTSD) with the use of nonmental health services. Method A case-comparison design enrolled 102 high users of health services and 54 low users who were assessed for PTSD diagnosis and severity of PTSD symptoms. Subjects were male veterans receiving services from the primary care clinics of the VA Boston Healthcare System during an 18-month period. Data were collected by interview by use of standardized instruments including the Clinician Administered PTSD Scale for DSM-IV, the Life Events Checklist, and the Beck Depression Inventory. Data analysis employed odds ratios, linear and logistic regression, and path analyses. Results High users of health care were almost twice as likely as low users (27.5% vs. 14.8%) to meet diagnostic criteria for current PTSD. The two groups differed significantly on both symptom frequency and intensity. Path analyses showed an indirect positive association between PTSD and health services use, with physician-diagnosed health conditions as a mediating variable. Auxiliary analysis demonstrated that the combined mental health burden of PTSD and depression symptoms also is positively associated with number of health conditions. Conclusions The findings indicate that PTSD, alone and in combination with depression, has a direct negative relationship with physical health that, in turn, is associated with more frequent use of primary health care services. These results do not suggest that PTSD leads to inappropriate (eg, distress-motivated) use of services.

Consistency of retrospective reporting about exposure to traumatic events.

Lifetime exposure to traumatic events was assessed by means of a multimethod protocol applied to 76 male military veterans. Consistency of retrospective reporting was determined for physical and sexual assault and abuse, accidents, disasters, combat and warzone experiences, serious illness or injury, and hazardous duty. Findings demonstrate that respondents are generally consistent in reporting traumatic events, although the majority report more events upon reevaluation. Reporting about traumatic events shows some variation as a function of the life epoch in which events occurred, whether they were directly or indirectly experienced, and the type of trauma involved. Discussion addresses memory-related processes triggered by trauma evaluation or tied to characteristics of events themselves as potential sources of inconsistency.

The internalizing and externalizing structure of psychiatric comorbidity in combat veterans

This study examined the latent structure of psychiatric disorders in a sample with a high prevalence of PTSD. A series of confirmatory factor analyses tested competing models for the covariation between Structured Clinical Interview for DSM-III-R diagnoses among 1,325 Vietnam veterans. The best-fitting solution was a 3-factor model that included two correlated internalizing factors: anxious-misery, defined by PTSD and major depression, and fear, defined by panic disorder/agoraphobia and obsessive-compulsive disorder. The third factor, externalizing, was defined by antisocial personality disorder, alcohol abuse/dependence, and drug abuse/dependence. Both substance-related disorders also showed significant, albeit smaller, cross-loadings on the anxious-misery factor. These findings shed new light on the structure of psychiatric comorbidity in a treatment-seeking sample characterized by high rates of PTSD.