Heart rate and QT interval variability: abnormal alpha-2 adrenergic function in patients with panic disorder

Effect of a Biofeedback Intervention on Heart Rate Variability in Individuals With Panic Disorder: A Randomized Controlled Trial

OBJECTIVE

Some individuals with panic disorder (PD) display reduced heart rate variability (HRV), which may result in an increased risk of cardiovascular mortality. Heart rate variability-biofeedback (HRV-BF) training has been shown to improve the modulation of the autonomic activity. Therefore, this randomized controlled trial was conducted to investigate the effect of a 4-week HRV-BF intervention in individuals with PD. HRV-BF training improved the modulation of the autonomic activity. Therefore, with this randomized controlled trial, we aimed to investigate the effect of a 4-week HRV-BF intervention in people with PD.

METHODS

Thirty-six women and 16 men with PD (mean age = 35.85 [15.60] years) were randomly allocated either to HRV-BF with 0.1-Hz breathing as intervention group or to HRV-Sham-BF as active control group. HRV-BF was performed for 4 weeks, whereas HRV was measured both during a short-term resting condition and during a paced breathing condition before and after intervention.

RESULTS

HRV-BF with 0.1-Hz breathing increased HRV and reduced panic symptoms in individuals with PD. HRV-BF with 0.1-Hz breathing demonstrated an increase in the time and frequency domain parameters of HRV during the short-term resting condition (ΔPost-Pre root mean square successive differences: 5.87 [14.03] milliseconds; ΔPost-Pre standard deviation of all NN intervals: 11.63 [17.06] milliseconds; ΔPost-Pre total power: 464.88 [1825.47] milliseconds2; ΔPost-Pre power in low-frequency range 0.04-0.15 Hz: 312.73 [592.71] milliseconds2), a decrease in the heart rate during the paced breathing condition (ΔPost-Pre: -5.87 [9.14] beats/min), and a decrease in the Panic and Agoraphobia Scale (ΔPost-Pre: -3.64 [6.30]). There was no intervention effect in the HRV-Sham-BF group.

CONCLUSIONS

HRV-BF as a noninvasive and nonpharmacological treatment seems to be an important intervention option to improve reduced HRV and decrease panic symptoms in individuals with PD. Future studies are needed to establish whether these effects translate to reductions in the risk of cardiovascular disease in PD.

The effect of physical activity on anxiety in children and young people: a systematic review and meta-analysis

BACKGROUND

There is emerging evidence that physical activity can have beneficial effects on anxiety. A comprehensive synthesis of the evidence of the anxiolytic effects of physical activity from randomised controlled trials (RCTs) in children and young people (CYP) is warranted.

METHODS

A search of 13 databases was conducted to identify RCTs testing the effects of physical activity on anxiety symptoms in children and young people (up to 25 years). Screening, data extraction and risk of bias assessment (using the Cochrane Collaboration tool for assessing risk of bias) were independently undertaken by two study authors. The primary analysis used a random effects model to compare the effect of physical activity interventions to no intervention or minimal intervention control conditions on state anxiety, assessed using validated, self-report measures.

RESULTS

Of the 3590 articles retrieved, 22 RCTs were included, with nine included in the primary meta-analysis. The overall standardised mean difference was 0.54 (95% CI -0.796, -0.28), representing a moderate improvement in state anxiety, compared to no intervention or minimal intervention control conditions. Physical activity was also found to produce significantly superior effects on state anxiety when compared to a time and attention-controlled group.

LIMITATIONS

The studies are of low quality overall, and there are a limited number of studies included in the meta-analyses therefore limiting the precision of results.

CONCLUSIONS

Physical activity may be a useful approach to addressing anxiety symptoms in children and young people, however, further trials of clinical populations are required to determine the effectiveness of physical activity as a treatment of anxiety disorders.

Ventricular Repolarization is Associated with Cognitive Function, but Not with Cognitive Decline and Brain Magnetic Resonance Imaging (MRI) Measurements in Older Adults

We aimed to investigate the cross-sectional and longitudinal associations of electrocardiogram (ECG)-based QT, QTc, JT, JTc, and QRS intervals with cognitive function and brain magnetic resonance imaging (MRI) measurements in a cohort of older individuals at increased risk for cardiovascular disease, but free of known arrhythmias. We studied 4627 participants (54% female, mean age 75 years) enrolled in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). Ten-second ECGs were conducted at baseline. Cognitive function was tested at baseline and repeated during a mean follow-up time of 3.2 years. Structural MRIs were conducted in a subgroup of 535 participants. Analyses were performed with multivariable (repeated) linear regression models and adjusted for cardiovascular risk-factors, co-morbidities, and cardiovascular drug use. At baseline, longer QT, JT, JTc—but not QTc and QRS intervals—were associated with a worse cognitive performance. Most notably, on the Stroop Test, participants performed 3.02 (95% CI 0.31; 5.73) seconds worse per standard deviation higher QT interval, independent of cardiovascular risk factors and medication use. There was no association between longer ventricular de- or repolarization and structural brain measurements. Therefore, specifically ventricular repolarization was associated with worse cognitive performance in older individuals at baseline but not during follow-up.

Non-linear Heart Rate Variability as a Discriminator of Internalizing Psychopathology and Negative Affect in Children With Internalizing Problems and Healthy Controls

Background: Internalizing psychopathology and dysregulated negative affect are characterized by dysregulation in the autonomic nervous system and reduced heart rate variability (HRV) due to increases in sympathetic activity alongside reduced vagal tone. The neurovisceral system is however, a complex nonlinear system, and nonlinear indices related to psychopathology are so far less studied in children. Essential nonlinear properties of a system can be found in two main domains: the informational domain and the invariant domain. sample entropy (SampEn) is a much-used method from the informational domain, while detrended fluctuation analysis (DFA) represents a widely-used method from the invariant domain. To see if nonlinear HRV can provide information beyond linear indices of autonomic activation, this study investigated SampEn and DFA as discriminators of internalizing psychopathology and negative affect alongside measures of vagally-mediated HRV and sympathetic activation. Material and Methods: Thirty-Two children with internalizing difficulties and 25 healthy controls (aged 9-13) were assessed with the Child Behavior Checklist and the Early Adolescent Temperament Questionnaire, Revised, giving an estimate of internalizing psychopathology, negative affect and effortful control, a protective factor against psychopathology. Five minute electrocardiogram and impedance cardiography recordings were collected during a resting baseline, giving estimates of SampEn, DFA short-term scaling exponent α1, root mean square of successive differences (RMSSD), and pre-ejection period (PEP). Between-group differences and correlations were assessed with parametric and non-parametric tests, and the relationships between cardiac variables, psychopathology and negative affect were assessed using generalized linear modeling. Results: SampEn and DFA were not significantly different between the groups. SampEn was weakly negatively related to heart rate (HR) in the controls, while DFA was moderately negatively related to RMSSD in both groups, and moderately positively related to HR in the clinical sample. SampEn was significantly associated with internalizing psychopathology and negative affect. DFA was significantly related to internalizing psychopathology. Conclusions: Higher invariant self-similarity was linked to less psychopathology. Higher informational entropy was related to less psychopathology and less negative affect, and may provide an index of the organizational flexibility of the neurovisceral system.

Energy Drinks and the Risk of Cardiovascular Disease: A Review of Current Literature

Energy drinks (EDs) are commonly used as a dietary supplement by young adolescents and adults. They are often used as a source of energy in order to enhance physical and mental performance. EDs contain a variety of substances, but caffeine is the main component. Safety has been the biggest concern associated with consuming EDs. Case reports, observational studies, and meta-analyses have been done in order to determine the effects of EDs on cardiovascular changes. The detrimental effects of EDs are cardiac arrhythmias, myocardial infarction, prolonged QT interval, aortic dissection, and death. In this article, we review case reports, observational studies, and meta-analyses of EDs and the risk of cardiovascular events and mortality. We also review active ingredients, pharmacokinetics, and the mechanism of action of EDs.

Arrhythmogenic effects of energy drinks

Energy drinks (ED) are increasingly popular, especially among adolescents and young adults. They are marketed as enhancers of energy, alertness, and physical performance. ED contain high doses of caffeine and other active ingredients. Their safety has come under question due to reports temporally linking ED consumption with serious cardiovascular events, including arrhythmias and sudden cardiac death. In this article, we report 2 cases of life-threatening ventricular arrhythmias in young patients after consuming ED. We also review the ingredients of ED, the physiologic effects on the cardiovascular system, and the available evidence suggesting arrhythmogenecity.

Executive Cognitive Functioning and Cardiovascular Autonomic Regulation in a Population-Based Sample of Working Adults

Objective: Executive cognitive functioning is essential in private and working life and is sensitive to stress and aging. Cardiovascular (CV) health factors are related to cognitive decline and dementia, but there is relatively few studies of the role of CV autonomic regulation, a key component in stress responses and risk factor for cardiovascular disease (CVD), and executive processes. An emerging pattern of results from previous studies suggest that different executive processes may be differentially associated with CV autonomic regulation. The aim was thus to study the associations between multiple measures of CV autonomic regulation and measures of different executive cognitive processes. Method: Participants were 119 healthy working adults (79% women), from the Swedish Longitudinal Occupational Survey of Health. Electrocardiogram was sampled for analysis of heart rate variability (HRV) measures, including the Standard Deviation of NN, here heart beats (SDNN), root of the mean squares of successive differences (RMSSD), high frequency (HF) power band from spectral analyses, and QT variability index (QTVI), a measure of myocardial repolarization patterns. Executive cognitive functioning was measured by seven neuropsychological tests. The relationships between CV autonomic regulation measures and executive cognitive measures were tested with bivariate and partial correlational analyses, controlling for demographic variables, and mental health symptoms. Results: Higher SDNN and RMSSD and lower QTVI were significantly associated with better performance on cognitive tests tapping inhibition, updating, shifting, and psychomotor speed. After adjustments for demographic factors however (age being the greatest confounder), only QTVI was clearly associated with these executive tests. No such associations were seen for working memory capacity. Conclusion: Poorer CV autonomic regulation in terms of lower SDNN and RMSSD and higher QTVI was associated with poorer executive cognitive functioning in terms of inhibition, shifting, updating, and speed in healthy working adults. Age could largely explain the associations between the executive measures and SDNN and RMSSD, while associations with QTVI remained. QTVI may be a useful measure of autonomic regulation and promising as an early indicator of risk among otherwise healthy adults, compared to traditional HRV measures, as associations between QTVI and executive functioning was not affected by age.

Cardiac autonomic function and vascular profile in subclinical hypothyroidism: Increased beat-to-beat QT variability

BACKGROUND

Patients with subclinical hypothyroidism (SH) may have higher incidence of coronary heart disease and autonomic dysfunction.

DESIGN OF THE STUDY

Prospective case control study.

AIM AND OBJECTIVES

To evaluate beat-to-beat QT variability and vascular stiffness in patients with SH compared to normal controls.

MATERIALS AND METHODS

We compared linear and nonlinear measures of cardiac repolarization liability using beat-to-beat QT intervals derived from the surface electrocardiogram during supine posture and vascular indices including pulse wave velocity and ankle-brachial index (ABI) during supine posture between female patients with SH and age- and sex-matched normal controls. Spectral analysis was done at very low frequency (LF) (0.003-0.04 Hz), Low frequency (LF) (0.04-0.15 Hz), and high frequency (HF) (0.15-0.4 Hz). The HF represents vagal regulation (parasympathetic) and LF represents both parasympathetic and sympathetic regulation.

RESULTS

We recruited 58 women with a mean age of 31.83 ± 8.9 years and 49 controls with mean age of 32.4 ± 9.9 years (P = NS). QT variability index (QTvi) was higher in cases compared to controls (P = 0.01). The ratio of LF/HF of R-R interval which is an index of sympathovagal tone was significantly more in cases compared to controls (P = 0.02). The difference in the left minus the right ABI was significant between cases and controls (P = 0.03).

CONCLUSIONS

The cases had lower parasympathetic activity as compared to controls, and there was a predominance of sympathetic activity in cases. QTvi may be an important noninvasive tool in this group of patients to study the risk of cardiovascular mortality.

QT interval variability in body surface ECG: measurement, physiological basis, and clinical value: position statement and consensus guidance endorsed by the European Heart Rhythm Association jointly with the ESC Working Group on Cardiac Cellular Electrophysiology

This consensus guideline discusses the electrocardiographic phenomenon of beat-to-beat QT interval variability (QTV) on surface electrocardiograms. The text covers measurement principles, physiological basis, and clinical value of QTV. Technical considerations include QT interval measurement and the relation between QTV and heart rate variability. Research frontiers of QTV include understanding of QTV physiology, systematic evaluation of the link between QTV and direct measures of neural activity, modelling of the QTV dependence on the variability of other physiological variables, distinction between QTV and general T wave shape variability, and assessing of the QTV utility for guiding therapy. Increased QTV appears to be a risk marker of arrhythmic and cardiovascular death. It remains to be established whether it can guide therapy alone or in combination with other risk factors. QT interval variability has a possible role in non-invasive assessment of tonic sympathetic activity.

Heart rate and respiratory response to doxapram in patients with panic disorder

Panic disorder (PD) is characterized by anticipatory anxiety and panic, both causing physiological arousal. We investigated the differential responses between anticipatory anxiety and panic in PD and healthy controls (HC). Subjects (15 PD and 30 HC) received an injection of a respiratory stimulant, doxapram, with a high rate of producing panic attacks in PD patients, or an injection of saline. PD subjects had significantly higher scores in anxiety and panic symptoms during both conditions. Analysis of heart rate variability (HRV) indices showed higher sympathetic activity (LF) during anticipatory anxiety and panic states, an increase in the ratio of LF/HF during the anticipatory and panic states and a decrease in parasympathetic (HF) component in PD patients. During doxapram PD subjects increased their LF/HF ratio while HC had a reduction in LF/HF. Parasympathetic component of HRV was lower during anticipatory anxiety in PD. In general, PD showed greater sympathetic and psychological responses related to anxiety and sensations of dyspnea, reduced parasympathetic responses during anticipatory and panic states, but no differences in respiratory response. This confirms previous studies showing that PD patients do not have an intrinsic respiratory abnormality (either heightened or dysregulated) at the level of the brain stem but rather an exaggerated fear response.

Abnormal Anterior Cingulate N-Acetylaspartate and Executive Functioning in Treatment-Resistant Depression After rTMS Therapy

BACKGROUND

Cognitive impairment is a key feature of treatment-resistant depression (TRD) and can be related to the anterior cingulate cortex (ACC) function. Repetitive transcranial magnetic stimulation (rTMS) as an antidepressant intervention has increasingly been investigated in the last two decades. However, no studies to date have investigated the association between neurobiochemical changes within the anterior cingulate and executive dysfunction measured in TRD being treated with rTMS.

METHODS

Thirty-two young depressed patients with treatment-resistant unipolar depression were enrolled in a double-blind, randomized study [active (n=18) vs. sham (n=14)]. ACC metabolism was investigated before and after high-frequency (15 Hz) rTMS using 3-tesla proton magnetic resonance spectroscopy (1H-MRS). The results were compared with 28 age- and gender-matched healthy controls. Executive functioning was measured with the Wisconsin Card Sorting Test (WCST) among 34 subjects with TRD and 28 healthy subjects.

RESULTS

Significant reductions in N-acetylaspartate (NAA) and choline-containing Compound levels in the left ACC were found in subjects with TRD pre-rTMS when compared with healthy controls. After successful treatment, NAA levels increased significantly in the left ACC of subjects and were not different from those of age-matched controls. In the WCST, more perseverative errors and fewer correct numbers were observed in TRD subjects at baseline. Improvements in both perseverative errors and correct numbers occurred after active rTMS. In addition, improvement of perseverative errors was positively correlated with enhancement of NAA levels in the left ACC in the active rTMS group.

CONCLUSIONS

Our results suggest that the NAA concentration in the left ACC is associated with an improvement in cognitive functioning among subjects with TRD response to active rTMS.

Molecular imaging for depressive disorders

Molecular imaging is the visualization, characterization, and measurement of biologic processes at the molecular and cellular levels in humans and other living systems. Molecular imaging techniques such as MR spectroscopy and PET have been used to explore the molecular pathophysiology of depression and assess treatment responses. MR spectroscopy is a noninvasive technique that assesses the levels of biochemical metabolites in the brain, while PET uses radioligands injected in the bloodstream that have high binding affinity for target molecules. MR spectroscopy findings suggest a role for glutamate/glutamine and gamma-aminobutyric acid in depression. PET has generally failed to find a correlation between radioligand binding potential and depression severity or treatment response, though it may offer promise in distinguishing responders and nonresponders to treatment. A major challenge for both modalities is that depression is a heterogeneous, multifactorial disorder, while MR spectroscopy and PET are limited to examining a few metabolites or a single radioligand at a time. This difference makes a comprehensive evaluation of neurochemical changes in the brain difficult.

Exploring exercise as an avenue for the treatment of anxiety disorders

Anxiety disorders constitute a significant public health problem. Current gold standard treatments are limited in their effectiveness, prompting the consideration of alternative approaches. In this review, we examine the evidence for exercise as an intervention for anxiety disorders. This evidence comes from population studies, studies of nonclinical anxiety reduction, as well as a limited number of studies of clinically anxious individuals. All of these studies provide converging evidence for consistent beneficial effects of exercise on anxiety, and are consistent with a variety of accounts of the mechanism of anxiety reduction with exercise. Further study of clinical populations is encouraged, as are studies of the mechanism of change of exercise interventions, which have the potential to help refine exercise intervention strategies. Likewise, studies that identify moderators of treatment efficacy will assist clinicians in deciding how and for whom to prescribe exercise.

Cost-effectiveness analysis of an occupational therapy-led lifestyle approach and routine general practitioner's care for panic disorder

OBJECTIVE

To assess the cost-effectiveness of an occupational therapy-led lifestyle approach to treating panic disorder in primary care compared with routine general practitioner's (GP) care. The burden of mental health disorders is considerable. Cost-effective interventions are necessary to alleviate some of these burdens. Habitual lifestyle behaviours influence mood, although to date mainly single lifestyle factor trials have been conducted to examine the effects on anxiety.

METHODS

An economic evaluation was conducted alongside an unblinded pragmatic randomised controlled trial with assessment at 5 and 10 months. Costs and consequences, as measured by the Beck anxiety inventory (BAI) and quality adjusted life years (QALYs), were compared using incremental cost-effectiveness ratios (ICERs).

RESULTS

The occupational therapy-led lifestyle intervention was more costly than routine GP care at both 5 and 10 months. Significant outcome improvements were evident at 5 months when using the BAI, although these were not maintained at 10 months. Small differences in mean QALYs were found. The estimated ICER was 36 pounds per BAI improvement for 5 months and 39 pounds for 10 months, and 18,905 pounds per QALY gained for 5 months and 8,283 pounds for 10 months.

CONCLUSIONS

If the maximum willingness to pay per additional QALY is 30,000 pounds, then there is an 86% chance that a lifestyle intervention may be considered to be value-for-money over 10 months.

Heart rate and blood pressure changes during autonomic nervous system challenge in panic disorder patients

OBJECTIVE

To test the hypothesis that panic disorder (PD) patients have a heightened or deregulated autonomic nervous system at rest and during autonomic challenge compared with healthy controls (HC); and to test a second hypothesis that severity of illness differentiates patients'; sympathovagal balance both at rest and during orthostatic challenge.

METHODS

Spectral analysis of heart rate (HR) and blood pressure was performed on 30 PD and 10 HC participants during an orthostatic challenge (head-up tilt).

RESULTS

PD patients presented higher HR (p < .001), lower heart rate variability (HRV) (p < .015), higher mean diastolic blood pressure (p < .006), higher low-frequency component of HR (p < .001), and a higher ratio of low-frequency to high-frequency component of HR (LF/HF) (p < .022) than HC at baseline. During tilt, PD patients responded with higher HR (p < .039), lower HRV (p < .043), increased mean diastolic blood pressure (p < .028), and a mild increase in LF/HF, whereas controls responded with a five-fold increase in LF/HF (p < .022). Patients with higher illness severity ratings (Clinical Global Impression Scale) showed higher HR (p < .002), lower HRV (p < .026), and a lower total power of systolic blood pressure (p < .02) compared with less ill patients.

CONCLUSION

These findings demonstrate a consistently higher or deregulated autonomic arousal in PD patients at rest and during orthostatic challenge compared with HC. These data also reveal a possible association between the level of anxiety illness severity and sympathovagal balance, which may imply greater cardiac risk.

Platelet serotonin transporter function and heart rate variability in patients with panic disorder

Many studies showed abnormal serotonin transporter (5-HTT) function and heart rate variability (HRV) in panic disorder patients. The present study investigated the relationship between HRV power spectral analysis findings and platelet serotonin uptake in panic disorder patients. Short-term HRV over 5 min and platelet serotonin transporter uptake parameters (V(max) and K(m)) were measured both in 45 patients with panic disorder and in 30 age-matched normal healthy control subjects. Low frequency power (LF) normalized unit (nu) and LF/high frequency power (HF) were significantly higher, whereas HF and HF nu were lower in the patient group than in the control group. V(max) and K(m) were all significantly lower (i.e., reflects decreased 5-HTT function) in patients with panic disorder than in normal controls. In the patient group, K(m) was negatively correlated with LF/HF and LF nu whereas no such correlations between them were found in the control group. By multivariate analysis based on multiple hierarchical linear regression, a low K(m) independently predicted an increased LF nu even after controlling for age, sex, and body mass index in the patient group. These results suggest that impaired 5-HTT function is closely related to dysregulation of autonomic nervous system in panic disorder.

The pNNx Heart Rate Variability Statistics: An Application to Neuroautonomic Dysfunction of Clozapine-Treated Subjects

OBJECTIVE

The percentage of successive normal cardiac interbeat intervals greater than 50 msec (pNN50) is a widely used heart rate variability measure, which is useful in identifying the neuroautonomic dysfunction of psychiatric disorders. However, pNN50 is only one member of a larger family of pNNx statistics, where x is greater than 0 msec. The potential application of the general pNNx statistics has not yet been explored in the psychiatric field. The authors examined the pNNx statistics in clozapine-treated subjects and normal controls to evaluate the usefulness of the general pNNx statistics.

METHODS

Sixty-one schizophrenic patients treated with clozapine and fifty-nine normal controls were evaluated. Probability values for the differences between the groups at each pNN value (range: pNN1-pNN100) were calculated using data obtained from a 30-minute electrocardiogram.

RESULTS

The conventional pNN50 and pNNx values with x<50 msec were all significantly lower in the patient group (p<0.05). The distinction between the two groups was more prominent at pNN values less than 50 msec than that observed at pNN50. The maximum separation between groups occurred at pNN5 (68.2+/-19.1 vs. 22.5+/-20.5, p<10(-22)).

CONCLUSION

The pNNx with x<50 msec provided more robust discrimination between the groups than the conventional pNN50, suggesting the importance of analyzing very small variations of interbeat interval in discriminating normal and pathological heart rate patterns. The results also suggest that the general pNNx statistics may be applied and useful in evaluating the neuroautonomic dysfunction in patients treated with clozapine, complementing the traditionally computed pNN50 value.

Effect of medication and psychotherapy on heart rate variability in panic disorder

BACKGROUND

Panic disorder (PD) patients have been shown to have reduced heart rate variability (HRV). Low HRV has been associated with elevated risk for cardiovascular disease. Our aim was to investigate the effects of treatment on heart rate (HR) in patients with PD through a hyperventilation challenge.

METHODS

We studied 54 participants, 43 with Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) PD and 11 controls. Subjects lay supine with their heads in a plastic canopy chamber, resting for 15 min and then breathing at a rate of 30 breaths per minute for 10 min. HRV was sampled for spectral analysis. Clinical and behavioral measures of anxiety were assessed. Treatment was chosen by patients: either 12 weeks of CBT alone or CBT with sertraline.

RESULTS

All patients showed significant decrease on clinical measures from baseline and 31 were treatment responders, 8 dropped out of the study before completion of the 12-week treatment phase and 4 were deemed nonresponders after 12 weeks of treatment. Although both treatments led to significant clinical improvement, only CBT alone demonstrated a significant reduction in HR and increase in HRV.

CONCLUSIONS

Our study replicated the finding that increased HR and decreased HRV occur in PD patients. Given the evidence of cardiac risk related to HRV, CBT appears to have additional benefits beyond symptom reduction. The mechanisms of this difference between CBT and sertraline are unclear and require further study.

Influences of lifestyle and general practice (GP) care on the symptom profile of people with panic disorder

Current treatment guidelines for anxiety disorders, including panic disorder (PD), recommend either medication or cognitive behavioural therapy (CBT). There is currently a call through the Layard Report for significant investment to increase the availability of CBT resources. However, there are reported limitations to both medication and CBT in the treatment of anxiety, and it appears prudent to consider additional methods of treatment that may offer effective interventions. One such intervention is based around the evidence of altered sensitivity within a number of physiological body systems in anxiety patients (particularly those with PD), all of which are influenced in their function by habitual lifestyle behaviours. A randomised controlled trial compared a 16‐week occupational therapy‐led lifestyle intervention and routine general practice (GP) care for PD. At 20 weeks, 14 symptoms with ‘moderate’ to ‘very severe’ ratings were assessed in 36 GP and 31 lifestyle‐intervention patients. Composite symptom profiles, similar at baseline, were produced. The GP intervention produced modest improvements in most symptoms. The lifestyle intervention overall produced greater symptomatic relief (Wilcoxon signed ranks test, P= 0.008). The physiological and cognitive symptom profile also changed more with lifestyle intervention. Occupational therapists have developed their interventions based on their understanding of everyday occupation. Habitual lifestyle behaviours are characterised as being recurrent elements of everyday occupation and are, therefore, legitimate targets for occupational therapy interventions. They provide a vehicle through which to encourage patients to regain understanding and control of their own anxiety symptoms.

Exaggerated beat-to-beat R amplitude variability in patients with panic disorder after intravenous isoproterenol

BACKGROUND

Anxiety symptoms are associated with a marked increase in sudden cardiac death, suggesting an abnormality in cardiac autonomic function. Our previous studies show a relationship between R amplitude variability and sympathetic function.

METHODS

We examined the effects of beta-adrenergic stimulation on R and T amplitude variability in panic disorder patients by infusing the beta-adrenergic agonist isoproterenol in 6 panic disorder patients and 11 normal subjects. The ECG signal was analyzed before the infusion and 5 min after the infusion was started. The outcome measures were the R and T detrended variance normalized for mean amplitudes (R(vm) and T(vm)) and the R(vi) and T(vi), measures which are normalized for the inter-beat interval variability in addition.

RESULTS

Patients with panic disorder had significantly more variability in R and T amplitude than normal controls and the R amplitude variability was increased further by beta-adrenergic stimulation with isoproterenol, which was more pronounced in the patients.

CONCLUSIONS

The isoproterenol-associated increase in R amplitude variability occurred in controls in the absence of significant anxiety. However, the increase in R amplitude variability was greater in patients with panic disorder, suggesting a greater sensitivity to beta-adrenergic effects of isoproterenol or to isoproterenol-induced anxiety.

Cardiac safety of central nervous system stimulants in children and adolescents with attention-deficit/hyperactivity disorder

OBJECTIVES

Case reports have raised concerns about the risk of cardiac events associated with central nervous system stimulants for the treatment of attention-deficit/hyperactivity disorder.

PATIENTS AND METHODS

This was a retrospective cohort study that used 10 years (July 1994 to June 2004) of Florida Medicaid claims data cross-linked to Vital Statistics Death Registry data. The cohort was composed of all youth 3 to 20 years old who were newly diagnosed with attention-deficit/hyperactivity disorder. Each month of follow-up was classified according to stimulant claims (methylphenidate, amphetamines, and pemoline) as current use (active stimulant claim), former use (time after periods of current use), or nonuse (time preceding the first stimulant claim, including follow-up of youth who were never exposed to stimulants). The study's end points were (1) cardiac death, (2) first hospital admission for cardiac causes or (3) first emergency department visit for cardiac causes. Risks were compared with time-dependent Cox regression analysis adjusting for various cardiac risk factors.

RESULTS

During 124,932 person-years of observation (n = 55,383), 73 youth died, 5 because of cardiac causes. No cardiac death occurred during 42,612 person-years of stimulant use. Hospital admissions for cardiac cause occurred for 27 children (8 during stimulant use, 11 during 35,671 person-years of former use, and 8 during 46,649 person-years of nonuse); and 1091 children visited the emergency department for cardiac causes (8.7 per 1000 person-years). Current stimulant use was associated with a 20% increase in the hazard for emergency department visits when compared with nonuse. No increased risk was found for periods of former use when compared with nonuse.

CONCLUSIONS

Incidence rates of cardiac events requiring hospitalization were small and similar to national background rates. Stimulants were associated with an increase in cardiac emergency department visits. More evidence is needed that addresses the long-term risk/benefit of the various treatment options and the effect of other cardiac risk factors and comedications.

Blood pressure, heart rate, and anxiety in schizophrenia

Anxiety may worsen outcome in psychotic disorders. We assessed anxiety in 44 acutely psychotic subjects and found a positive association with heart rate and blood pressure. Risperidone treatment reduced anxiety but increased heart rate. We concluded that anxiety may adversely affect cardiovascular status in schizophrenia, but the anxiolytic effect of risperidone is not straightforward.

A pragmatic, unblinded randomised controlled trial comparing an occupational therapy-led lifestyle approach and routine GP care for panic disorder treatment in primary care

BACKGROUND

Treated anxiety increased in the UK by over 30% since 1994. Medication and psychological treatment is most common, but outcomes are sometimes poor, with high relapse rates. Lifestyle has a potential role in treatment, but is not considered in clinical guidelines. Panic disorder is potentially influenced by lifestyle factors.

METHODS

16 week unblinded pragmatic randomised controlled trial in 15 East of England primary care practices (2 Primary Care Trusts). Participants met DSM-IV criteria for panic disorder with/without agoraphobia. Follow-up at 20 weeks and 10 months. Control arm, unrestricted routine GP care. Trial Arm, Occupational therapy-led lifestyle treatment comprising: lifestyle review of fluid intake, diet pattern, exercise, caffeine, alcohol and nicotine; negotiation of positive lifestyle changes; monitoring and review of impact of changes.

PRIMARY OUTCOME MEASURE

Beck Anxiety Inventory.

DATA ANALYSIS

Intention-to-treat analysis provided between-group comparisons using analysis of co-variance. Bonferroni method to adjust p-values.

RESULTS

From 199 referrals, 36 GP care and 31 lifestyle arm patients completed to final follow-up. Significantly lower lifestyle arm BAI scores at 20 weeks (p<0.001), non-significant (p=0.167) at 10 months after Bonferroni correction. 63.6% lifestyle arm, and 40% GP arm patients (p=0.045) panic-free at 20 weeks; 67.7% and 48.5% (p=0.123) respectively at 10 months.

LIMITATIONS

Final study size/power calls for caution in interpreting findings.

CONCLUSIONS

A lifestyle approach may provide a clinically effective intervention at least as effective as routine GP care, with significant improvements in anxiety compared with routine GP care at the end of treatment. Further study is required before suggesting practice changes.

Pharmacologic reduction of CNS noradrenergic activity in PTSD: the case for clonidine and prazosin

This article reviews the neurobiologic rationale for and presents clinical guidance concerning the use of medications that reduce central nervous system noradrenergic activity in the treatment of intrusive symptoms of posttraumatic stress disorder. The authors reviewed neurobiological studies, nonclinical studies using animal models, clinical case reports, open-label drug studies, and blinded, placebo-controlled drug studies. This review of the basic science and clinical literature, and the authors' clinical experience with culturally and demographically diverse populations, indicate that clonidine and prazosin can play a useful role in treating sleep disturbance and hyperarousal in posttraumatic stress disorder, with minimal adverse effects and low financial cost.

An autonomic flexibility–neurovisceral integration model of anxiety and cardiac vagal tone

Research on heart rate variability (HRV), cardiac vagal tone, and their relationship to anxiety is reviewed in the context of the autonomic flexibility and neurovisceral integration models of adaptive functioning. These perspectives address the qualities of response flexibility and inhibition across multiple levels, incorporating central and autonomic nervous system mechanisms of environmental engagement, as well as principles derived from non-linear dynamics. These models predict reduced HRV and vagal tone in anxiety, and the literature has generally supported this prediction, with exceptions as are noted. State, trait, and clinical expressions of anxiety are considered, along with the clinical, methodological, and theoretical implications of this research. A portrayal of anxiety as a restricted response range across biological and behavioral realms of functioning is drawn from the literature on anxiety and HRV.

Altered coordination of the neuroendocrine response during psychosocial stress in subjects with high trait anxiety

Contradicting data are available on stress responsiveness in subjects with high anxiety. In the present study we tested the hypothesis that high trait anxiety is associated with impaired coordination of the stress response, rather than global hypo- or hyper-responsiveness. The sample consisted of subjects with high (n=15) and with low (n=12) trait anxiety. Subjects with middle-range levels of anxiety were excluded from the study. After psychological characterization, the volunteers were exposed to a public speech procedure. A spectrum of neuroendocrine parameters was measured before, during and after the procedure and the results were analyzed by exploratory statistics. Psychological characterization of subjects revealed a lower preference for task-oriented but a higher one for emotion-oriented coping strategies as well as lower scores on hardiness in subjects with high trait anxiety. After the speech procedure, differences in selected mood and personality characteristics were observed, with the anxious group scoring significantly higher in scales for stress, tiredness, arousal, anxiety and depression. Factor analysis revealed that one common factor grouped blood pressure, catecholamine concentrations in blood and heart rate in non-anxious subjects, while three distinct factors separated these parameters in anxious subjects. Correlation analysis in anxious subjects showed that lower adrenocorticotropin (ACTH) and cortisol responses during stress were associated with exaggerated perception of stress and worse mental performance. Our findings indicate that subjects with high anxiety have different relationships between specific neuroendocrine parameters, subjective perception of stress and Stroop test performance.

Panic symptoms at the interface of body and mind

Panic disorder is a common illness with significant impact on function and, at times, disabling consequences. Advances over recent years have yielded potential pathophysiologic mechanisms, including neurotransmitter systems and neural substrates. This article provides an overview of various models and hypotheses regarding the etiology of panic disorder. Because its symptoms overlap with the symptoms of various medical disorders, this discussion reviews the comorbidity of panic disorder with medical conditions, especially cardiac and respiratory disorders.

Power spectrum analysis and cardiovascular morbidity in anxiety disorders

Spectral analysis of heart rate variability (HRV) and related measures has been shown to be a reliable noninvasive technique enabling quantitative assessment of cardiovascular autonomic regulatory responses to autonomic regulatory mechanisms; it provides a dynamic probe of sympathetic and parasympathetic tone, reflecting the interactions between the two. Over 20 studies reported abnormalities of HRV in anxiety, and patients with heart disease and anxiety are at increased risk for morbidity and mortality. Psychiatric drugs partly correct abnormalities of HRV and, recently, autonomic drugs (beta-blockers) have been studied in anxiety disorders. The authors call for further studies, especially in patients with co-existing anxiety disorders and heart disease, incorporating assessment of HRV.

Venlafaxine extended-release capsules in panic disorder: flexible-dose, double-blind, placebo-controlled study

BACKGROUND

Venlafaxine extended-release (ER) has proven efficacy in the treatment of anxiety symptoms in major depression, generalised anxiety disorder and social anxiety disorder.

AIMS

To evaluate the efficacy, safety and tolerability of venlafaxine ER in treating panic disorder.

METHOD

Adult out-patients (n=361) with panic disorder were randomly assigned to receive venlafaxine ER (75-225 mg/day) or placebo for up to 10 weeks in a double-blind study.

RESULTS

Venlafaxine ER was not associated with a greater proportion of patients free from full-symptom panic attacks at the final on-therapy evaluation, but was associated with lower mean panic attack frequency and a higher proportion free from limited-symptom panic attacks, higher response and remission rates, and improvements in anticipatory anxiety, fear and avoidance. Adverse events were comparable with those of the drug in depression and anxiety disorders.

CONCLUSIONS

Venlafaxine ER seems to be effective and well tolerated in the short-term treatment of panic disorder.

Anxiety and medical disorders

Anxiety symptoms and disorders are associated with a range of general medical disorders. This association may be a physiologic consequence of the general medical disorder, a psychologic reaction to the experience of having a medical illness, a side effect of treatment, or a chance occurrence. This article briefly reviews the associations of panic disorder with seizure disorder, Klüver-Bucy syndrome, mitral valve prolapse, and respiratory disorders; of generalized anxiety disorder with chronic obstructive airway disease and cardiovascular and endocrine disorders; of social anxiety disorder with Parkinson's disease; of obsessive-compulsive disorder with striatal disorders; and of posttraumatic stress disorder with head injury and pain. Such associations provide important clues for understanding the neurobiology of anxiety disorders.