Psychobiological Measures Research Articles

Enhanced exposure therapy for combat-related Posttraumatic Stress Disorder (PTSD): Study protocol for a randomized controlled trial

BackgroundPTSD, which has been identified in up to 23% of post-9-11 veterans, often results in a chronic, pernicious course. Thus, effective treatments are imperative. The Institute of Medicine (IOM) concluded that the only intervention for PTSD with sufficient evidence to conclude efficacy is exposure therapy. This Phase III trial compares the efficacy of exposure therapy for combat-related PTSD delivered in two different formats- via virtual reality exposure therapy (VRE) or prolonged exposure therapy (PE)- combined with D-Cycloserine (DCS), a cognitive enhancer shown to facilitate the extinction of fear. Methods/designMilitary personnel of any duty status and civilians deployed to Iraq and Afghanistan were eligible. Participants were randomly assigned to 9 sessions of exposure therapy (VRE or PE) and medication (50 mg DCS or placebo). Participants were treated at three geographically diverse sites. Participants were re-assessed at 3-months post-treatment. The co-primary hypotheses are that (1) DCS will augment response to exposure therapy (both VRE and PE) on PTSD symptoms; (2) VRE will be associated with greater improvement than PE. Genetic and psychophysiological markers will be evaluated as potential moderators and mediators of treatment outcomes as well as secondary outcomes. DiscussionThis study is the first to compare the relative efficacy of DCS-augmented VRE versus PE on PTSD symptoms. The design has several advantages: participants received an active, effective treatment and predictors of response to treatment included genetic and psychobiological measures. The results may directly influence the future delivery of services, and contribute to the development of a standardized treatment protocol.Trial registration: NCT01352637.

Brain-behavior relationships in externalizing: P3 amplitude reduction reflects deficient inhibitory control

The use of endophenotypes to classify individuals at risk for or suffering from psychopathology has been criticized for lacking specificity and predictive utility. This issue is apparent in research on externalizing, a heritable predisposition to disinhibitory psychopathology and personality traits. Numerous studies have shown that P3 amplitude reduction (P3AR) reliably reflects externalizing, implicating P3AR as a candidate endophenotype for externalizing psychopathology. However, this endophenotype has not been connected directly to a key deficit in executive function (e.g., inhibitory control) commonly related to externalizing. Using a modified oddball task in a sample (N=74) of at-risk adolescents and young adults, we examined the associations among externalizing, P3AR, and inhibitory control. We also examined the associations of P3AR and inhibitory control with frequency of real-world disinhibited behavior. Results indicated that externalizing related to P3AR, which in turn related to deficient inhibitory control. Additionally, there were both unique and interactive associations of P3 amplitude and inhibitory control with indicators of real-world behavior. These findings provide the first direct evidence that P3AR reflects deficits in inhibitory control, thus linking this externalizing-related endophenotype to a specific cognitive process. Moreover, the results highlight the value of considering psychobiological measures alongside behavioral measures for indexing risk for externalizing behavior and psychopathology.

Evidence for an association between mineralocorticoid receptor gene haplotypes and psychobiological measures of atypical depression

Evidence for an association between mineralocorticoid receptor gene haplotypes and psychobiological measures of atypical depression

The influence of neuroticism and psychological symptoms on the assessment of images in three-dimensional emotion space.

Objective: The present study investigated the influence of neuroticism (NEO Five-Factor Inventory (NEO-FFI)) and psychological symptoms (Brief Symptom Inventory (BSI)) on pleasure, arousal, and dominance (PAD) ratings of the International Affective Picture System (IAPS). Methods: The subjects (N=131) were presented with images from the IAPS (30 images) and new images (30 images). The influence of neuroticism and BSI (median split: high vs. low) on the assessment of pleasure, arousal and dominance of the images was examined. Correlations of pleasure, arousal and dominance were presented in a 3-D video animation.Results: Subjects with high scores (compared to subjects with low scores by median split) of neuroticism and psychological symptoms of the BSI rated the presented emotional images more negative in the valence dimension (pleasure), higher in arousal and less dominant. Conclusion: Neuroticism and psychological symptoms influence the subjective emotional evaluation of emotional images. Therefore the location in the three-dimensional emotion space depends on individual differences. Such differences must be kept in mind, if correlations between emotion ratings and other variables like psychobiological measures are analyzed.

Application of Psychobiological Measures in Occupational Science and Occupational Therapy Research

The authors discuss the use of psychobiological measures (i.e., biomarkers) for furthering understanding of the biological foundations supporting human occupational behavior. They explore the possible applications of psychobiological measures in research relevant to occupational therapy practice and occupational science, including the documentation of outcomes following occupational therapy intervention. Common psychobiological measures that are available and of particular interest to occupational scientists and therapists are described based on a review of research that has applied psychobiological measures. Psychobiological measures have rarely been reported in the occupational science and occupational therapy literature to date, although such measures are beginning to emerge as researchers expand their questions and methods related to occupational engagement. Psychobiological measures may provide promising insights into the effectiveness of interventions designed to improve self-regulation and more effectively manage stressors for enhancing occupational performance. These measures also may be used to increase understanding of how participation in desired occupations influences arousal levels, stress response, and overall states of well-being and productivity.

The strong situation: A potential impediment to studying the psychobiology and pharmacology of anxiety disorders

The strong situation, as formulated by social psychologists, refers to an experimental condition offering unambiguous stimuli predicting or constituting hedonically strong events that uniformly guide response sets across individuals. In relation to fear and anxiety, the strong situation results from the unambiguous threat of an imminent and dangerous stimulus that evokes the adaptive fear response among anxiety patients and healthy controls alike. The current paper describes evidence that weakening the experimental situation through reducing the certainty, temporal proximity, and/or potency of the aversive stimulus may facilitate the emergence of patient–control differences in psychobiological measures of anxious arousal. Additionally, weak situations may be useful for testing the clinical utility of anxiolytic agents, given that pharmacological treatments of anxiety disorders are not intended to reduce the adaptive, normative response likely evoked by strong threat situations.

Psychobiological heterogeneity of familial and sporadic schizophrenia

Although schizophrenia is presumed to be heterogeneous, there has been limited success distinguishing familial from sporadic cases. We used psychobiological measures to examine heterogeneity, as they may be closer to neurobiology than symptoms. Smooth pursuit eye movement quality (SPEM) and dichotic listening (DL) tests to tones and words were used to assess hemispheric laterality asymmetry. Forty-six research unit patients participated in assessments of family history (FH) and physiological measures. FH was categorized by three exclusive groups: FH-1 patients had a chronic schizophrenia-related psychosis in a first-degree relative, FH-2 had it in second-degree relative, and FH-3 had no family member with a reoccurrence. Analysis of variance showed a significant group difference for SPEM and DL tones. SPEM was significantly worse in all three schizophrenia groups than for the normal comparison subjects. Among the schizophrenia groups, the nonfamilial group (FH-3) had the worst SPEM quality, FH-2 had intermediate quality, and FH-1 had the best quality. Conversely, only the nonfamilials (FH-3) had normal right hemispheric lateralization for tones, whereas familials did not, and FH-2 again had intermediate values. The lateralization quotient for DL words did not significantly differ among the groups. SPEM was affected most in sporadic, not familial schizophrenia, whereas dichotic listening was most affected in familial schizophrenia. This double dissociation supports the utility of the familial/sporadic distinction and suggests that etiological factors in different forms of schizophrenia may impact principally on distinct neurobiological substrates, despite similar patient phenomenology.