The psychophysiology of generalized anxiety disorder: 1. Pretreatment characteristics

Walking on the bright side: Associations between affect, depression, and gait

Background

Psychomotor change is a core symptom of depression and one of the criteria in diagnosing depressive disorders. Research suggests depressed individuals demonstrate deviations in gait, or walking, compared to non-depressed controls. However, studies are sparse, often limited to older adults and observational gait assessment. It is also unclear if gait changes are due to dysregulation of affect, a core feature of depression. The current study addressed this gap by investigating the relation between positive and negative affect, depressive symptom severity, and gait in young adults.

Methods

Using three-dimensional motion capture, gait parameters (velocity, stride length, and step time) were attained from 90 young adults during a task where they walked ten meters at their own pace overground in a laboratory for ten minutes. Self-report measures of mood and affect were collected.

Results

On average, the study population reported high negative and low positive affect. Contrary to our hypotheses, hierarchical regressions demonstrated no significant associations between gait parameters and affective or depressive symptoms (ps>.05).

Conclusions

Our findings do not support a relation between affective symptoms and gait parameters. The results may indicate age-dependent gait pathology or that other symptoms of depression may influence gait more strongly than affect. They may also reflect an observational bias of gait changes in depressed young adults, one that is unsupported by objective data. Replication is warranted to further examine whether affective symptomology is embodied via gait differences in young adults.

Bispectral Index Alterations and Associations With Autonomic Changes During Hypnosis in Trauma Center Researchers: Formative Evaluation Study

BACKGROUND

Previous work performed by our group demonstrated that intermittent reductions in bispectral index (BIS) values were found during neurofeedback following mindfulness instructions. Hypnosis was induced to enhance reductions in BIS values.

OBJECTIVE

This study aims to assess physiologic relaxation and explore its associations with BIS values using autonomic monitoring.

METHODS

Each session consisted of reading a 4-minute baseline neutral script and playing an 18-minute hypnosis tape to 3 researchers involved in the BIS neurofeedback study. In addition to BIS monitoring, autonomic monitoring was performed, and this included measures of electromyography (EMG), skin temperature, skin conductance, respiratory rate, expired carbon dioxide, and heart rate variability. The resulting data were analyzed using two-tailed t tests, correlation analyses, and multivariate linear regression analyses.

RESULTS

We found that hypnosis was associated with reductions in BIS (P<.001), EMG (P<.001), respiratory rate (P<.001), skin conductance (P=.006), and very low frequency power (P=.04); it was also associated with increases in expired carbon dioxide (P<.001), skin temperature (P=.04), high frequency power (P<.001), and successive heart interbeat interval difference (P=.04) values. Decreased BIS values were associated with reduced EMG measures (R=0.76; P<.001), respiratory rate (R=0.35; P=.004), skin conductance (R=0.57; P<.001), and low frequency power (R=0.32; P=.01) and with increased high frequency power (R=-0.53; P<.001), successive heart interbeat interval difference (R=-0.32; P=.009), and heart interbeat interval SD (R=-0.26; P=.04) values.

CONCLUSIONS

Hypnosis appeared to induce mental and physical relaxation, enhance parasympathetic neural activation, and attenuate sympathetic nervous system activity, changes that were associated with BIS values. Findings from this preliminary formative evaluation suggest that the current hypnosis model may be useful for assessing autonomic physiological associations with changes in BIS values, thus motivating us to proceed with a larger investigation in trauma center nurses and physicians.

The late positive potential as a neurocognitive index of emotion regulatory flexibility

A growing body of research has examined regulatory flexibility as the ability to dynamically modulate emotional expression and experience (Bonanno & Burton, 2013). The late positive potential (LPP), an event-related potential reflecting processing of emotionally-evocative stimuli, is sensitive to emotion regulation (ER) or the psychological processes that underlie the experience, expression, and management of emotions. However, few studies have used the LPP to index regulatory flexibility or tested its association with self-reported emotional well-being and ER. The results of the current study showed that regulatory flexibility indexed via the LPP was associated with self-reported use of specific ER strategies. Further, greater regulatory flexibility measured as the full LPP regulatory range (indexed following prompts to enhance and suppress emotional responses to stimuli) was specifically and uniquely associated with greater self-reported coping flexibility. Findings provide preliminary support for this neurocognitive approach to conceptualizing and assessing regulatory flexibility.

Low baseline pCO2 predicts poorer outcome from behavioral treatment: evidence from a mixed anxiety disorders sample

Low levels of end-tidal partial pressure of carbon dioxide (pCO2)-the amount of carbon dioxide measured from expired air-are commonly found in individuals with anxiety disorders but have not been examined as predictors of outcome from anxiety treatment. The current study examined pre-treatment baseline pCO2 as a predictor of outcome from cognitive behavioral therapy (CBT) and acceptance and commitment therapy (ACT) for anxiety disorders. Sixty-one individuals with a Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) defined principal anxiety disorder diagnosis completed 12 sessions of either CBT or ACT. Baseline pCO2 was measured prior to entering treatment. Self-reported anxiety symptoms and quality of life were assessed at pre-treatment, post-treatment, and 6- and 12-month follow-up from baseline. Low baseline pCO2 was associated with higher anxiety symptoms and lower quality of life across follow-up timepoints, above and beyond baseline symptom severity. These results suggest that low baseline pCO2 predicts poorer outcome from CBT and ACT for anxiety and may warrant treatment that directly addresses respiratory dysregulation.

Leadership is associated with lower levels of stress

As leaders ascend to more powerful positions in their groups, they face ever-increasing demands. As a result, there is a common perception that leaders have higher stress levels than nonleaders. However, if leaders also experience a heightened sense of control--a psychological factor known to have powerful stress-buffering effects--leadership should be associated with reduced stress levels. Using unique samples of real leaders, including military officers and government officials, we found that, compared with nonleaders, leaders had lower levels of the stress hormone cortisol and lower reports of anxiety (study 1). In study 2, leaders holding more powerful positions exhibited lower cortisol levels and less anxiety than leaders holding less powerful positions, a relationship explained significantly by their greater sense of control. Altogether, these findings reveal a clear relationship between leadership and stress, with leadership level being inversely related to stress.

Do unexpected panic attacks occur spontaneously?

BACKGROUND

Spontaneous or unexpected panic attacks, per definition, occur "out of the blue," in the absence of cues or triggers. Accordingly, physiological arousal or instability should occur at the onset of, or during, the attack, but not preceding it. To test this hypothesis, we examined if points of significant autonomic changes preceded the onset of spontaneous panic attacks.

METHODS

Forty-three panic disorder patients underwent repeated 24-hour ambulatory monitoring. Thirteen natural panic attacks were recorded during 1960 hours of monitoring. Minute-by-minute epochs beginning 60 minutes before and continuing to 10 minutes after the onset of individual attacks were examined for respiration, heart rate, and skin conductance level. Measures were controlled for physical activity and vocalization and compared with time matched control periods within the same person.

RESULTS

Significant patterns of instability across a number of autonomic and respiratory variables were detected as early as 47 minutes before panic onset. The final minutes before onset were dominated by respiratory changes, with significant decreases in tidal volume followed by abrupt carbon dioxide partial pressure increases. Panic attack onset was characterized by heart rate and tidal volume increases and a drop in carbon dioxide partial pressure. Symptom report was consistent with these changes. Skin conductance levels were generally elevated in the hour before, and during, the attacks. Changes in the matched control periods were largely absent.

CONCLUSIONS

Significant autonomic irregularities preceded the onset of attacks that were reported as abrupt and unexpected. The findings invite reconsideration of the current diagnostic distinction between uncued and cued panic attacks.

Treating chronic worry: Psychological and physiological effects of a training programme based on mindfulness

The present study examines psychological and physiological indices of emotional regulation in non-clinical high worriers after a mindfulness-based training programme aimed at reducing worry. Thirty-six female university students with high Penn State Worry Questionnaire scores were split into two equal intervention groups: (a) mindfulness, and (b) progressive muscle relaxation plus self-instruction to postpone worrying to a specific time of the day. Assessment included clinical questionnaires, daily self-report of number/duration of worry episodes and indices of emotional meta-cognition. A set of somatic and autonomic measures was recorded (a) during resting, mindfulness/relaxation and worrying periods, and (b) during cued and non-cued affective modulation of defence reactions (cardiac defence and eye-blink startle). Both groups showed equal post-treatment improvement in the clinical and daily self-report measures. However, mindfulness participants reported better emotional meta-cognition (emotional comprehension) and showed improved indices of somatic and autonomic regulation (reduced breathing pattern and increased vagal reactivity during evocation of cardiac defense). These findings suggest that mindfulness reduces chronic worry by promoting emotional and physiological regulatory mechanisms contrary to those maintaining chronic worry.

Diversity of effective treatments of panic attacks: what do they have in common?

By comparing efficacious psychological therapies of different kinds, inferences about common effective treatment mechanisms can be made. We selected six therapies for review on the basis of the diversity of their theoretical rationales and evidence for superior efficacy: psychoanalytic psychotherapy, hypercapnic breathing training, hypocapnic breathing training, reprocessing with and without eye-movement desensitization, muscle relaxation, and cognitive behavior therapy. The likely common element of all these therapies is that they reduce the immediate expectancy of a panic attack, disrupting the vicious circle of fearing fear. Modifying expectation is usually regarded as a placebo mechanism in psychotherapy, but may be a specific treatment mechanism for panic. The fact that this is seldom the rationale communicated to the patient creates a moral dilemma: Is it ethical for therapists to mislead patients to help them? Pragmatic justification of a successful practice is a way out of this dilemma. Therapies should be evaluated that deal with expectations directly by promoting positive thinking or by fostering non-expectancy.

Change point analysis for longitudinal physiological data: detection of cardio-respiratory changes preceding panic attacks

Statistical methods for detecting changes in longitudinal time series of psychophysiological data are limited. ANOVA and mixed models are not designed to detect the existence, timing, or duration of unknown changes in such data. Change point (CP) analysis was developed to detect distinct changes in time series data. Preliminary reports using CP analysis for fMRI data are promising. Here, we illustrate the application of CP analysis for detecting discrete changes in ambulatory, peripheral physiological data leading up to naturally occurring panic attacks (PAs). The CP method was successful in detecting cardio-respiratory changes that preceded the onset of reported PAs. Furthermore, the changes were unique to the pre-PA period, and were not detected in matched non-PA control periods. The efficacy of our CP method was further validated by detecting patterns of change that were consistent with prominent respiratory theories of panic positing a relation between aberrant respiration and panic etiology.

Psychophysiological correlates of generalized anxiety disorder with or without comorbid depression

It remains uncertain whether generalized anxiety disorder (GAD) and major depressive disorder (MDD) represent two separate diagnostic entities. The goal of this study was to examine whether comorbid MDD distinguishes individuals with GAD on a psychophysiological level during an experimentally-induced worrying procedure. Participants included 39 individuals with GAD, 14 of whom met the criteria for MDD. During the experimental procedure, participants were asked to worry or relax after an initial baseline phase while measuring their heart rate, high frequency heart rate variability (HF-HRV), skin conductance level, and subjective level of anxiety. The two groups did not differ in their subjective anxiety, heart rate response, and skin conductance levels. However, participants with comorbid MDD had greater HF-HRV values throughout the experiment than did those without MDD. At baseline, HF-HRV was significantly correlated with a self-report measure of depression. These results suggest that individuals with comorbid GAD and MDD can be distinguished based on HF-HRV from individuals with GAD but without MDD. These results support the distinction between GAD and MDD.

Generalized anxiety disorder: between now and DSM-V

This article presents the current evidence base for pharmacotherapy of generalized anxiety disorder (GAD) and an update on the phenomenology of GAD and its association with other psychiatric and somatic conditions. It discusses nosological issues and suggests ways to improve recognition, treatment, and care for patients who have GAD.