Randomized clinical trial of capnometry-assisted respiratory training in veterans with posttraumatic stress disorder hyperarousal.

OBJECTIVE: To investigate whether capnometry-assisted antihyperventilation respiratory training, successful in treating panic, and sleep hygiene instructions would reduce posttraumatic stress disorder (PTSD) hyperarousal symptoms in U.S. military veterans. METHOD: We conducted a parallel, nonblinded clinical trial and randomized 80 veterans with PTSD hyperarousal into treatment or wait list. Primary treatment outcomes from baseline to 1st follow-up were analyzed using mixed modeling. Baseline physiological measures were compared between the PTSD hyperarousal group and a no-PTSD group (n = 68). RESULTS: Baseline respiration rate but not partial-pressure of end-tidal carbon dioxide (PCO2) was higher in the PTSD hyperarousal group than in the no-PTSD group during 3 min of quiet sitting, indicating no difference in baseline hyperventilation. There was no significant effect of the intervention on PTSD hyperarousal symptoms or hyperventilation compared to wait list, but treatment did lower respiratory rate. CONCLUSION: This intervention did not reduce PTSD hyperarousal symptoms, perhaps due to differences between underlying mechanisms of PTSD hyperarousal and panic disorder or to differences between veteran and civilian populations. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Habituation or Normalization? Experiential and Respiratory Recovery From Voluntary Hyperventilation in Treated Versus Untreated Patients With Panic Disorder.

Psychophysiological theories postulate respiratory dysregulation as a mechanism contributing to panic disorder (PD). Additionally, symptomatic and respiratory recovery from voluntary hyperventilation (HVT-recovery) have been shown to lag in PD and it is unclear if HVT-recovery normalizes with treatment. Thirty-seven panic disorder patients were randomized to hypoventilation therapy (TX, n = 20) or waitlist control (WL, n = 17) (Meuret et al., 2008). In a secondary analysis, their HVT-recovery was analyzed at pre- and post-TX/WL, compared to 29 healthy controls (HC). HVT included three phases: 5-min baseline, 3-min hyperventilation, and 8-min recovery. HVT-elicited symptom severity and anxiety were rated following each phase, and end-tidal PCO2 and respiratory rate (RR) were recorded throughout. Treatment, compared to WL, was highly effective in reducing PD pathology (d=2.21, Meuret et al., 2008). At pre-TX/WL, PD demonstrated delayed HVT-recovery PCO2 and higher RR. Treated patients demonstrated normalization of HVT-recovery for PCO2 and RR; however, improvements of HVT-recovery for symptom severity and anxiety did not differ between TX and WL. Results replicate pretreatment HVT respiratory recovery abnormalities in PD and further demonstrate normalization, comparable to HC, following successful treatment. The results provide support for respiratory dysregulation as a feature of PD and demonstrate the utility of HVT respiratory recovery as treatment outcome measure for respiration-based PD therapy.

Supplementing sleep actigraphy with button pressing while awake.

OBJECTIVE/BACKGROUND: Wrist-worn sleep actigraphs are limited for evaluating sleep, especially in sleepers who lie awake in bed without moving for extended periods. Sleep logs depend on the accuracy of perceiving and remembering times of being awake. Here we evaluated pressing an event-marker button while lying awake under two conditions: self-initiated pressing every 5 to 10 minutes or pressing when signaled every 5 minutes by a vibration pulse from a wristband. We evaluated the two conditions for acceptability and their concordance with actigraphically scored sleep. PARTICIPANTS AND METHODS: Twenty-nine adults wore actigraphs on six nights. On nights 1 and 4, they pressed the marker to a vibration signal, and on nights 2 and 5, they self-initiated presses without any signal. On nights 3 and 6, they were told not to press the marker. Every morning they filled out a sleep log about how they had slept. RESULTS: The vibration band was unacceptable to 42% of the participants, who judged it too disturbing to their sleep. Self-initiated pressing was acceptable to all, although it reduced log reported sleep depth compared to a no pressing condition. Estimations of sleep onset latency were considerably longer by button pressing than by actigraphy. Agreement of epoch-by-epoch sleep scoring by actigraphy and by button pressing was poor (kappa = 0.23) for self-initiated pressing and moderate (kappa = 0.46) for pressing in response to a vibration. CONCLUSIONS: Self-initiated button pressing to indicate being awake while lying in bed is acceptable to many, interferes little with sleep, and adds substantially to the information given by actigraphy.

Effects of psychosocial and physical stress on lactate and anxiety levels.

Both intense physical activity and potent psychosocial stressors increase blood lactate. Raising lactate levels by infusing the chemical can have an anxiogenic effect. Here, we compare the relationship between changes in lactate and anxiety levels resulting from two standardized stressors. We investigated the effects of the Multiple Wingate All-Out Performance Test (WG), a strong physical stressor, and the Trier Social Stress Test (TSST), a well-documented psychosocial stressor, in 32 healthy young men using a crossover design. Before and after each stressor, venous blood was analyzed for lactate levels and the State-Trait-Anxiety Inventory (STAI) was given. Both stressors raised both lactate and anxiety significantly above their baseline levels. While the rise in lactate was much higher for the WG than for the TSST, the rises in anxiety were nearly equal. Individual fitness did not influence the results for lactate or anxiety. No significant relation between lactate and anxiety changes were found. Thus, our results as well as the literature suggest that lactate is an important variable for understanding the impact of sport participation.

Hypoventilation Therapy Alleviates Panic by Repeated Induction of Dyspnea.

BACKGROUND: Previous research has shown that hypoventilation therapy reduces panic symptoms in part by increasing basal partial pressure of carbon dioxide (PCO2) levels. We tested an additional pathway by which hypoventilation therapy could exert its therapeutic effects: through repeated interoceptive exposure to sensations of dyspnea. METHODS: A total of 35 patients with panic disorder were trained to perform exercises to raise their end-tidal PCO2 levels using a portable capnometry device. Anxiety, dyspnea, end-tidal PCO2, and respiratory rate were assessed during each exercise across 4 weeks of training. Mixed-model analysis examined whether within-exercise levels of dyspnea were predictive of reduction of panicogenic cognitions. RESULTS: As expected, within-exercise anxiety and respiratory rate decreased over time. Unexpectedly, PCO2 dropped significantly from the beginning to the end of exercise, with these drops becoming progressively smaller across weeks. Dyspnea increased and remained consistently above basal levels across weeks. As hypothesized, greater dyspnea was related to significantly lower panicogenic cognitions over time even after controlling for anxiety and PCO2. Additional exploratory analyses showed that within-exercise increases in dyspnea were related to within-exercise increases in anxiety but were not related to within-exercise increases in PCO2. CONCLUSIONS: In support of the interoceptive exposure model, we found that greater dyspnea during hypoventilation exercises resulted in lower panicogenic cognitions even after the effect of PCO2 was taken into account. The findings offer an additional important target in panic treatment.

Assessing sleep quality using self-report and actigraphy in PTSD.

Sleep disturbance is commonly reported by participants with post-traumatic stress disorder, but objective evidence of poor sleep is often absent. Here we compared self-report and actigraphic evaluations of sleep between veterans with post-traumatic stress disorder and controls. Participants reported their sleep retrospectively for the month before the recording night and on the recording night. On the recording night, they wore an Actiwatch-64 and were instructed to press the marker button upon getting into bed, each time they awoke, and at their final awakening. The post-traumatic stress disorder group reported much worse sleep than controls on the Pittsburgh Sleep Quality Index for the previous month and somewhat poorer sleep on the recording night. However, on the recording night, neither diary nor actigraphic measures of number of awakenings, total time in bed, nor time lying awake after sleep onset differed between participants with and without post-traumatic stress disorder. Diary-reported number of awakenings was fewer than actigraphically captured awakenings. These results suggest a memory bias towards remembering worse sleep on the nights before the recording night.

Effects of therapeutic relationship, expectancy, and credibility in breathing therapies for anxiety.

The authors investigated the effects of the quality of the therapeutic alliance, expectancy of improvement, and credibility of treatment on the outcome of two breathing therapies for anxiety and panic. Data were collected during a randomized clinical trial evaluating the efficacy of two theoretically opposing, end-tidal pCO2 feedback-assisted breathing therapies for patients experiencing anxiety attacks. In this study, five weekly individual breathing therapy sessions were administered for the patients who were experiencing anxiety attacks as symptoms of various anxiety disorders. The outcome of this trial indicated that regardless of the opposing breathing instructions (raise or lower pCO2) used in the two breathing therapies, patients in both treatment groups improved equally after treatment. Nonspecific factors rather than the different directions of pCO2 changes could have played a role in the improvement. Regression analyses showed that for both therapies patient-rated therapeutic alliance was predictive of improvement at the 1-month follow-up, and that patient-rated confidence that the therapy would produce improvement, an aspect of its credibility, accounted for almost half of the variance in improvement at the 6-month follow-up. Thus, two factors usually considered nonspecific were identified to be potent predictors of treatment outcome.

Autonomic arousal during actigraphically estimated waking and sleep in male veterans with PTSD.

Physiological hyperarousal is manifested acutely by increased heart rate, decreased respiratory sinus arrhythmia, and increased skin conductance level and variability. Yet it is uncertain to what extent such activation occurs with the symptomatic hyperarousal of posttraumatic stress disorder (PTSD). We compared 56 male veterans with current PTSD to 54 males who never had PTSD. Subjects wore ambulatory devices that recorded electrocardiograms, finger skin conductance, and wrist movement while in their normal environments. Wrist movement was monitored to estimate sleep and waking periods. Heart rate, but not the other variables, was elevated in subjects with PTSD equally during waking and during actigraphic sleep (effect sizes, Cohen's d, ranged from 0.63 to 0.89). The length of the sleep periods and estimated sleep fragmentation did not differ between groups. Group heart rate differences could not be explained by differences in body activity, PTSD hyperarousal symptom scores, depression, physical fitness, or antidepressant use.

Psychiatry on trial: the Norway 2011 massacre.

On July 22, 2011, Anders Breivik, a Norwegian citizen, detonated a fertilizer bomb near government buildings in Oslo, killing eight people, and then proceeded to a nearby island where the Labor Party was holding a youth camp. There, he killed 69 people before being arrested. Just before these events, he posted a "compendium" on the Web explaining his actions and encouraging others to do likewise. Much of the ensuing media coverage and trial focused on whether he was sane and whether he had a psychiatric diagnosis. One team of court-appointed psychiatrists found him to be psychotic with a diagnosis of paranoid schizophrenia and legally insane. A second team found him neither psychotic nor schizophrenic and, thus, legally sane. Their contrary opinions were not reconciled by observing his behavior in court. We discuss why experienced psychiatrists reached such fundamentally opposing diagnostic conclusions about a "home-grown" terrorist holding extreme political views.

Worried sleep: 24-h monitoring in high and low worriers.

BACKGROUND: Commonly used trait measures might not accurately capture the relationship between worry and sleep difficulties in real life. METHODS: In a 24-h ambulatory monitoring study, high and low trait worriers maintained a log of worry and sleep characteristics while actigraphy, heart rates (HR), skin conductance (SC), and ambient temperature were recorded. RESULTS: Worrying in bed on the night of the recording was associated with longer self-reported and actigraphic nocturnal awakenings, lower actigraphic sleep efficiency, higher HR, lower HR variability, elevated SC level, and more non-specific SC fluctuations compared to not worrying in bed. High trait worriers had higher HR during waking and sleep, and reported shorter total sleep time and poorer sleep quality. CONCLUSIONS: While trait worry is mainly associated with subjective sleep difficulties, worrying in bed impairs sleep according to both subjective and objective sleep parameters, including heightened sympathetic and reduced parasympathetic activation.

Experiential, autonomic, and respiratory correlates of CO2 reactivity in individuals with high and low anxiety sensitivity.

Psychometric studies indicate that anxiety sensitivity (AS) is a risk factor for anxiety disorders such as panic disorder (PD). To better understand the psychophysiological basis of AS and its relation to clinical anxiety, we examined whether high-AS individuals show similarly elevated reactivity to inhalations of carbon dioxide (CO2) as previously reported for PD and social phobia in this task. Healthy individuals with high and low AS were exposed to eight standardized inhalations of 20% CO2-enriched air, preceded and followed by inhalations of room air. Anxiety and dyspnea, in addition to autonomic and respiratory responses were measured every 15 s. Throughout the task, high AS participants showed a respiratory pattern of faster, shallower breathing and reduced inhalation of CO2 indicative of anticipatory or contextual anxiety. In addition, they showed elevated dyspnea responses to the second set of air inhalations accompanied by elevated heart rate, which could be due to sensitization or conditioning. Respiratory abnormalities seem to be common to high AS individuals and PD patients when considering previous findings with this task. Similarly, sensitization or conditioning of anxious and dyspneic symptoms might be common to high AS and clinical anxiety. Respiratory conditionability deserves greater attention in anxiety disorder research.

Opposing breathing therapies for panic disorder: a randomized controlled trial of lowering vs raising end-tidal P(CO2).

BACKGROUND: Teaching anxious clients to stop hyperventilating is a popular therapeutic intervention for panic. However, evidence for the theory behind this approach is tenuous, and this theory is contradicted by an opposing theory of panic, the false-suffocation alarm theory, which can be interpreted to imply that the opposite would be helpful. OBJECTIVE: To test these opposing approaches by investigating whether either, both, or neither of the 2 breathing therapies is effective in treating patients with panic disorder. METHOD: We randomly assigned 74 consecutive patients with DSM-IV-diagnosed panic disorder (mean age at onset = 33.0 years) to 1 of 3 groups in the setting of an academic research clinic. One group was trained to raise its end-tidal P(CO2) (partial pressure of carbon dioxide, mm Hg) to counteract hyperventilation by using feedback from a hand-held capnometer, a second group was trained to lower its end-tidal P(CO2) in the same way, and a third group received 1 of these treatments after a delay (wait-list). We assessed patients physiologically and psychologically before treatment began and at 1 and 6 months after treatment. The study was conducted from September 2005 through November 2009. RESULTS: Using the Panic Disorder Severity Scale as a primary outcome measure, we found that both breathing training methods effectively reduced the severity of panic disorder 1 month after treatment and that treatment effects were maintained at 6-month follow-up (effect sizes at 1-month follow-up were 1.34 for the raise-CO(2) group and 1.53 for the lower-CO(2) group; P < .01). Physiologic measurements of respiration at follow-up showed that patients had learned to alter their P(CO2) levels and respiration rates as they had been taught in therapy. CONCLUSIONS: Clinical improvement must have depended on elements common to both breathing therapies rather than on the effect of the therapies themselves on CO(2) levels. These elements may have been changed beliefs and expectancies, exposure to ominous bodily sensations, and attention to regular and slow breathing. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00183521.

Publication recommendations for electrodermal measurements.

This committee was appointed by the SPR Board to provide recommendations for publishing data on electrodermal activity (EDA). They are intended to be a stand-alone source for newcomers and experienced users. A short outline of principles for electrodermal measurement is given, and recommendations from an earlier report (Fowles et al., ) are incorporated. Three fundamental techniques of EDA recording are described: (1) endosomatic recording without the application of an external current, (2) exosomatic recording with direct current (the most widely applied methodology), and (3) exosomatic recording with alternating current-to date infrequently used but a promising future methodology. In addition to EDA recording in laboratories, ambulatory recording has become an emerging technique. Specific problems that come with this recording of EDA in the field are discussed, as are those emerging from recording EDA within a magnetic field (e.g., fMRI). Recommendations for the details that should be mentioned in publications of EDA methods and results are provided.

Airway constriction in asthma during sustained emotional stimulation with films.

BACKGROUND: Individuals with asthma have been shown to respond to unpleasant stimuli with bronchoconstriction, but little is known about the time course of responding during sustained emotional stimulation and whether it varies with patients' experience. OBJECTIVE: To examine the time course of oscillatory resistance (R(os)) during emotionally evocative films in 15 asthma patients and 14 healthy controls. METHODS: Participants viewed unpleasant, surgery, and neutral films, each ranging 3-5min in duration. R(os) and the respiratory pattern (respiration rate, tidal volume, minute ventilation) were monitored continuously. Following each film, participants rated their affective response and symptoms. The time course of R(os) during films was explored using multilevel modeling. RESULTS: Compared to neutral film sequences, unpleasant films (including those with surgery scenes) elicited a uniform pattern of initial increases in R(os) with peaks within the first 1-2min, followed by a gradual decline. Increases were more pronounced in asthma and during surgery films. Including additional respiratory parameters as time-varying covariates did not affect the temporal course of R(os) change. The rate of decline in R(os) (after the initial increase) was less in participants who experienced greater arousal and in patients who reported more shortness of breath. Patients more susceptible to psychological triggers in daily life showed slower rates of decline in R(os). CONCLUSION: The temporal course of bronchoconstriction to unpleasant stimulation is highly uniform in asthma, with strong constriction in early stages of stimulation. More sustained constriction in emotion-induced asthma could be a risk factor for developing asthma exacerbation in daily life.

Separation anxiety disorder in children: disorder-specific responses to experimental separation from the mother.

BACKGROUND: Separation anxiety disorder (SAD) is one of the most common anxiety disorders in childhood and is predictive of adult anxiety disorders, especially panic disorder. However, the disorder has seldom been studied and the attempt to distinguish SAD from other anxiety disorders with regard to psychophysiology has not been made. We expected exaggerated anxiety as well as sympathetic and respiratory reactivity in SAD during separation from the mother. METHOD: Participants were 49 children with a principal diagnosis of SAD, 21 clinical controls (CC) with a principal diagnosis of anxiety disorder other than SAD, and 39 healthy controls (HC) not meeting criteria for any current diagnosis. Analyses of covariance controlling for age were used to assess sympathetic and parasympathetic activation (preejection period and respiratory sinus arrhythmia) as well as cardiovascular (heart rate, mean arterial pressure, total peripheral resistance), respiratory (total breath time, minute ventilation, tidal volume, end-tidal CO(2) , respiratory variability), electrodermal, and self-report (anxiety, cognitions, symptoms) variables during baseline, 4-min separation from, and reunion with the mother. RESULTS: Children with a diagnosis of SAD were characterized by elevated self-reported anxiety responses to separation and increased sympathetic reactivity compared with CC and HC groups. The SAD group also displayed greater vagal withdrawal and higher reactivity in multiple cardiovascular, respiratory, and electrodermal measures compared with the HC group, while corresponding responses were less in the CC group and not significantly different from the other groups. CONCLUSIONS: Separation from the mother elicits greater autonomic, respiratory, and experiential responses in children with SAD. Our findings based on brief experimental separation demonstrate differential subjective and physiological manifestations of specific anxiety diagnoses, thus supporting the validity of the diagnostic category of SAD.

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.

Effects of breathing training on voluntary hypo- and hyperventilation in patients with panic disorder and episodic anxiety.

Anxiety disorders are associated with respiratory abnormalities. Breathing training (BT) aimed at reversing these abnormalities may also alter the anxiogenic effects of biological challenges. Forty-five Panic Disorder (PD) patients, 39 Episodic Anxiety patients, and 20 non-anxious controls underwent voluntary hypoventilation and hyperventilation tests twice while psychophysiological measures were recorded. Patients were randomized to one of two BT therapies (Lowering vs. Raising pCO(2)) or to a waitlist. Before treatment panic patients had higher respiration rates and more tidal volume instability and sighing at rest than did non-anxious controls. After the Lowering therapy, patients had lower pCO(2) during testing. However, neither reactivity nor recovery to either test differed between patients and controls, or were affected by treatment. Although the two treatments had their intended opposite effects on baseline pCO(2), other physiological measures were not affected. We conclude that baseline respiratory abnormalities are somewhat specific to PD, but that previously reported greater reactivity and slower recovery to respiratory challenges may be absent.