Psychophysiological correlates of anxiety: a single-case study

Physiological correlates of anxiety in childhood and adolescence: A systematic review and meta-analysis

Anxiety is one of the most prevalent problems that affects children and adolescents. The vast majority of diagnostic tools for anxiety depend on written or verbal reports from children and adolescents or their significant others. The validity and reliability of such reports can be compromised by their subjective nature. Thus, there is growing interest in whether anxiety can be indexed with objective physiological measures. The key aim of this systematic review and meta-analysis was to determine which physiological measures are most reliably associated with elevated levels of anxiety amongst children and adolescents. Online databases (e.g., PsycINFO, Embase, Medline) were searched for relevant studies according to pre-determined criteria. Twenty-five studies comprising 2502 participants (N = 1160 with high anxiety) met inclusion, identifying 11 groups of physiological measures. Our meta-analysis revealed that skin conductance level is the most sensitive measure of anxiety (d = 0.83), followed by electromyography (EMG) measures (d = 0.71) and skin conductance response (d = 0.58). However, the included studies varied in terms of subjective measures, study designs, experimental task measures, and physiological measures. Consideration of these differences in methodology offer potential directions for future research.

Interventions to reduce adult state anxiety, dental trait anxiety, and dental phobia: A systematic review and meta-analyses of randomized controlled trials

This review evaluates randomized controlled trials (RCTs) intervening on adult state anxiety (fear and emotional distress during dental treatment), chronic dental (trait) anxiety or dental phobia (disproportionately high trait anxiety; meeting diagnostic criteria for specific phobia). Seven online databases were systematically searched. 173 RCTs met inclusion criteria, of which 67 qualified for 14 pooled analyses. To alleviate state anxiety during oral surgery, moderate-certainty evidence supports employing hypnosis (SMD=-0.31, 95 %CI[-0.56,-0.05]), and low-certainty evidence supports prescribing benzodiazepines (SMD=-0.43, [-0.74,-0.12]). Evidence for reducing state anxiety is inconclusive regarding psychotherapy, and does not support virtual reality exposure therapy (VRET), virtual reality distraction, music, aromatherapy, video information and acupuncture. To reduce trait anxiety, moderate-certainty evidence supports using Cognitive Behavioral Therapy (CBT; SMD=-0.65, [-1.06, -0.24]). Regarding dental phobia, evidence with low-to-moderate certainty supports employing psychotherapy (SMD=-0.48, [-0.72,-0.24]), and CBT specifically (SMD=-0.43, [-0.68,-0.17]), but not VRET. These results show that dental anxieties are manageable and treatable. Clinicians should ensure that interventions match their purpose-managing acute emotions during treatment, or alleviating chronic anxiety and avoidance tendencies. Existing research gaps underscore the necessity for future trials to minimize bias and follow CONSORT reporting guidelines.

Heart rate variability in patients with agoraphobia with or without panic disorder remains stable during CBT but increases following in-vivo exposure

Patients with anxiety disorders have a lower heart rate variability (HRV) than healthy controls. Low HRV is associated with cardiovascular disease and dysfunction of the autonomic nervous system (ANS). The aim of the present study was to investigate if HRV in patients with agoraphobia with or without panic disorder can be influenced by cognitive behavioral therapy (CBT). 73 patients with agoraphobia with or without panic disorder were included in the study. Heart rate (HR) and HRV were recorded at rest before and after CBT and during in-vivo exposure. No changes in HR and HRV were observed throughout therapy. During in-vivo exposure HRV increased significantly and HR exhibited a tendency to decrease. Despite clinical improvement of anxiety symptoms, ANS activity at rest did not seem to be influenced by CBT. However, during in-vivo exposure, HRV changed significantly, indicating a higher parasympathetic activity at the end of exposure.

Conditioned stimulus presentations alter anxiety level in fear-conditioned mice

It is generally believed that fear is rapidly triggered by a distinct cue while anxiety onset is less precise and not associated with a distinct cue. Although it has been claimed that both processes can be measured with certain independence of each other, it is unclear how exactly they differ. In this study, we measured anxiety in mice that received discriminative fear conditioning using behavioral, heart rate and calcium (Ca²⁺) responses in the ventral hippocampal CA1 (vCA1) neurons. We found that the occurrence of fear significantly interfered with anxiety measurements under various conditions. Diazepam reduced basal anxiety level but had no effect during the presentation of conditioned stimulus (CS). Injection of an inhibitory peptide of PKMzeta (ZIP) into the basolateral amygdala almost entirely abolished CS-triggered fear expression and reduced anxiety to basal level. Heart rate measures suggested a small reduction in anxiety during CS-. Calcium responses in the lateral hypothalamus-projecting vCA1 neurons showed a steady decay during CS suggesting a reduced anxiety. Thus, under our experimental conditions, CS presentations likely reduce anxiety level in the fear-conditioned mice.

Working mechanisms of a general positivity approach-avoidance training: Effects on action tendencies as well as on subjective and physiological stress responses

BACKGROUND AND OBJECTIVES

The general positivity training, a Cognitive Bias Modification procedure modifying individuals' approach-avoidance tendencies to positively and negatively valenced pictures by means of a joystick task, has been proven effective in attenuating stress reactivity in dysphoric students. The present study explored which training component (pull positive pictures, push negative pictures, or both) is the active one in changing action tendencies and stress responses.

METHODS

Two-hundred-and-thirteen students completed one of four approach-avoidance trainings before being exposed to a stressful speech-task: The general positivity training (pull positive and push negative pictures), a training to approach positive pictures and avoid empty pictures (ApP), a training to avoid negative pictures and approach empty pictures (AvN), or a sham-training.

RESULTS

The pattern of results suggests that the groups trained to avoid negative pictures showed a stronger increase in positive approach-avoidance tendencies than the other two groups. However, only the positivity training induced significant within-group changes in positive bias. The groups further did not differ in self-report or cardiovascular measures of anxiety in response to the stress-task. Instead, the training affected mood directly: Exposure to negative pictures during the training increased state anxiety.

LIMITATIONS

Generalizability of the findings is limited by using an unselected student sample. Also, the use of empty pictures as neutral stimuli in the ApP and AvN could have weakened training effects in these groups.

CONCLUSIONS

Although our results hint at the importance of avoiding negative pictures for modifying an approach-avoidance bias, only the positivity training with both components may effectively induce a positive bias. Remarkably, we failed to replicate and extend previously reported effects of the training on stress-responses. Hence, it remains questionable whether the changes in bias reflect changes in underlying cognitive processing tendencies or task-specific learning effects.

Identifying Patterns in Complex Field Data

Abstract. Ambulatory assessment methods are well suited to examine how patients with panic disorder and agoraphobia (PD/A) undertake situational exposure. But under complex field conditions of a complex treatment protocol, the variability of data can be so high that conventional analytic approaches based on group averages inadequately describe individual variability. To understand how fear responses change throughout exposure, we aimed to demonstrate the incremental value of sorting HR responses (an index of fear) prior to applying averaging procedures. As part of their panic treatment, 85 patients with PD/A completed a total of 233 bus exposure exercises. Heart rate (HR), global positioning system (GPS) location, and self-report data were collected. Patients were randomized to one of two active treatment conditions (standard exposure or fear-augmented exposure) and completed multiple exposures in four consecutive exposure sessions. We used latent class cluster analysis (CA) to cluster heart rate (HR) responses collected at the start of bus exposure exercises (5 min long, centered on bus boarding). Intra-individual patterns of assignment across exposure repetitions were examined to explore the relative influence of individual and situational factors on HR responses. The association between response types and panic disorder symptoms was determined by examining how clusters were related to self-reported anxiety, concordance between HR and self-report measures, and bodily symptom tolerance. These analyses were contrasted with a conventional analysis based on averages across experimental conditions. HR responses were sorted according to form and level criteria and yielded nine clusters, seven of which were interpretable. Cluster assignment was not stable across sessions or treatment condition. Clusters characterized by a low absolute HR level that slowly decayed corresponded with low self-reported anxiety and greater self-rated tolerance of bodily symptoms. Inconsistent individual factors influenced HR responses less than situational factors. Applying clustering can help to extend the conventional analysis of highly variable data collected in the field. We discuss the merits of this approach and reasons for the non-stereotypical pattern of cluster assignment across exposures.

The tripartite model of fear in children with specific phobias: assessing concordance and discordance using the behavioral approach test

Lang's tripartite model posits that three main components characterize a fear response: physiological arousal, cognitive (subjective) distress, and behavioral avoidance. These components may occur in tandem with one another (concordance) or they may vary independently (discordance). The behavioral approach test (BAT) has been used to simultaneously examine the three components of the fear response. In the present study, 73 clinic-referred children and adolescents with a specific phobia participated in a phobia-specific BAT. Results revealed an overall pattern of concordance: correlation analyses revealed the three indices were significantly related to one another in the predicted directions. However, considerable variation was noted such that some children were concordant across the response components while others were not. More specifically, based on levels of physiological arousal and subjective distress, two concordant groups (high arousal-high distress, low arousal-low distress) and one discordant (high arousal-low distress or low arousal-high distress) group of youth were identified. These concordant and discordant groups were then compared on the percentage of behavioral steps completed on the BAT. Analyses revealed that the low arousal-low distress group completed a significantly greater percentage of steps than the high arousal-high distress group, and a marginally greater percentage of steps than the discordant group. Potential group differences associated with age, gender, phobia severity, and phobia type were also explored and no significant differences were detected. Implications for theory and treatment are discussed.

Temporal stability and coherence of anxiety, dyspnea, and physiological variables in panic disorder

Twenty-five panic disorder (PD) patients, 19 social phobics (SP), and 20 healthy controls (HC) sat quietly for 15 min, rating their anxiety and dyspnea every 30s while respiratory, cardiovascular, and electrodermal responses were recorded. No panic attacks were reported. For self-reported anxiety and dyspnea, within-subject variability over time was higher in PD than in SP or HC. In PD within-subject correlations across 30-s epochs were significant for (a) self-reported anxiety versus dyspnea, end-tidal pCO2, minute volume, duty cycle, skin conductance level, and interbeat interval, and for (b) dyspnea versus end-tidal pCO2, minute volume, tidal volume, and inspiratory flow rate. Several positive or negative correlations were greater in PD than in other groups. Thus in PD, experienced anxiety and dyspnea are temporally unstable but are correlated with each other and with fluctuations in respiratory and autonomic variables, even in the absence of panic attacks.