Ambulatory heart rate changes in patients with panic attacks

Ambulatory monitoring of panic patients during regular activity: a preliminary report

Ten patients with panic disorder and 10 matched control subjects were compared as to their blood pressure and heart rate during regular daily activity. Physiological responses were monitored by ambulatory recorder, and subjective reports of mood were collected. Data were analyzed controlling for activity and stress level of the subjects. Diastolic blood pressure emerged as a possible discriminatory factor between the groups. A trend for higher heart rate occurred in the panic group. In behavioral terms, panic patients tended to avoid anxiety-provoking situations, resulting in anxiety ratings comparable to those of the control group. Thus, recorded physiological differences between the groups may reflect heightened baseline autonomic activity in panic patients.

Spells: in search of a cause

OBJECTIVE

To determine the cause of spells, present clinical features, and discuss diagnostic approaches.

DESIGN

Relevant medical literature is reviewed, and three illustrative cases are presented.

RESULTS

Spells are a sudden onset of a symptom or symptoms that are stereotypic, self-limited, and recurrent. A spell involves both subjective perceptions and objective findings. In the assessment of patients who have spells, use of a systematic approach is important in determining the cause. The causes of spells include endocrine, cardiovascular, psychologic, pharmacologic, neurologic, and other miscellaneous disorders. A comprehensive history, physical examination, and basic laboratory studies are important in the initial assessment. Specialized testing is usually needed and directed by clinical suspicion based on the spell "phenotype" (for example, a pheochromocytoma, carcinoid syndrome, or mast cell disease) and the type of facial flush or pallor.

CONCLUSION

In the assessment of the patient who has spells, the clinician should cast a wide but defensible diagnostic net. Initial studies should be directed by the clues obtained from the history and physical examination.

Differential effects of methylphenidate on working memory in ADHD children with and without comorbid anxiety

OBJECTIVE

To examine the effects of methylphenidate (MPH) on working memory and behavior in anxious and nonanxious children with attention-deficit hyperactivity disorder (ADHD).

METHOD

A total of 40 ADHD children (22 nonanxious, 18 anxious) completed a randomized, double-blind, placebo-controlled, crossover trial with three doses (0.3, 0.6, 0.9 mg/kg) of MPH. A serial addition task was used to assess working memory; direct observation of motor activity indexed behavior.

RESULTS

MPH improved working memory in the nonanxious ADHD group but not in the comorbidity anxious group. By contrast, MPH reduced activity level in both groups. The presence of concurrent learning disabilities did not influence stimulant response.

CONCLUSIONS

The presence of comorbid anxiety in children with ADHD predicts a less robust response to stimulant treatment and suggests that ADHD with anxiety may constitute a distinct and clinically meaningful subtype of ADHD.

The 35% CO2 challenge in panic disorder: optimization by receiver operating characteristic (ROC) analysis

To test the power of the 35% CO2 test as a challenge for panic disorder (PD), and to set an ideal threshold of discrimination between patients and controls, we analysed by receiver operating characteristic (ROC) analysis the responses of 91 out-patients with PD and 46 controls who inhaled a 35% CO2/65% O2 gas mixture. ROC analysis confirmed that the CO2 challenge discriminates well between PD patients and controls, with 86% probability to classify them correctly on the basis of subjective anxiety after the test. A relatively modest increment in subjective anxiety (i.e. an absolute increment of 20 units, or a relative increment of 26% of subjective anxiety) proved to be the ideal threshold to separate the two groups of our sample.

Cholecystokinin and anxiety in normal volunteers: an investigation of the anxiogenic properties of pentagastrin and reversal by the cholecystokinin receptor subtype B antagonist L-365,260

1. Two studies were undertaken to develop a model of experimentally induced anxiety in normal volunteers based on cholecystokinin (CCK) receptor agonism/antagonism. 2. In Study 1 rapid intravenous injections of the CCK receptor subtype B (CCKB) agonist pentagastrin (0.15, 0.3 and 0.6 micrograms kg-1) were found to produce dose-related increases in subjective ratings of anxiety compared with placebo. 3. In Study 2 the effects of pre-treatment with two doses of the CCKB receptor antagonist L-365,260 (10 mg, 50 mg p.o.) on the anxiety induced by pentagastrin 0.3 micrograms kg-1 i.v. were investigated. Detailed measurements of blood pressure and pulse rate were also undertaken. Pentagastrin produced changes in blood pressure and pulse rate which had a similar time course to that observed for subjective anxiety ratings. L-365,260 reversed both the autonomic and anxiogenic effects of pentagastrin. 4. The pentagastrin model would appear to be a useful tool for investigating potential anxiolytics in normal volunteers.

The role of negative self-statements during exposure in vivo. A process study of eight panic disorder patients with agoraphobia

The purpose of this study was to evaluate the pattern of cognitive change, and in particular the role of negative self-statements, in relation to improvement during an in vivo exposure treatment. Eight panic disordered patients with agoraphobia, of whom 4 were most and 4 were least improved on a composite measure, were exposed to standardized agoraphobic situations. During the exposure, heart rate, self-statements, and subjective anxiety were registered throughout the sessions. Fixed criteria were set for habituation of heart rate and reduction of subjective anxiety within a session. Results showed that the total frequency of negative self-statements at the start, during, as well as at the end of treatment differentiated best between the most and least improved patients. These results suggest that it may be therapeutically wise to continue exposure therapy not only until habituation of anxiety (subjectively and physiologically) is achieved, but also until the frequency of negative self-statements is reduced until zero.

Continuous monitoring of panic

Data on naturally occurring panic attacks were gathered through continuous self-monitoring for 94 patients suffering from panic disorder with agoraphobia. A total of 1276 panic attacks were collected. In this article various aspects of panic attacks, including severity, duration and time of onset and situations in which panic occurs are addressed. In addition, the symptoms of panic were investigated, examining the (in)variability of attacks within each patient and the patterning of symptoms in the entire group of patients. The most important findings were as follows: attacks occurred predominantly in nonphobic situations; nocturnal panic attacks were generally more severe than attacks during the day; symptom patterns across various attacks, stemming from the same patient, were rather variable; and finally, a substantial number of the attacks (40%) did not meet the DSM-III-R criteria for number of symptoms.

Sleep in panic disorders

Panic disorder is a common anxiety disorder, which has relatively often its onset during adolescence. Besides panic attacks and avoidance behavior the patients often have sleep disturbances. They suffer from insomnia, nocturnal panic attacks, fear of going to bed or falling asleep and drug- or alcohol-related symptoms such as withdrawal phenomena.

Testing the suffocation false alarm theory of panic disorder

The need for hypotheses concerning the nature of those functions that have been impaired in stereotyped psychiatric syndromes is emphasized. With regard to panic disorder, the key role of the spontaneous panic attack became apparent from several viewpoints. However, panics seem to be a type of misreleased fear, which guided the thinking concerning the nature of possible psychological or physiological malfunctions. We indicate that spontaneous panic cannot be fear, but must represent some other malfunction and suggest that the spontaneous panic is a suffocation false alarm. The development of this idea is outlined, and attempts to develop tests of this hypothesis are indicated. In particular, studies of children with congenital central hypoventilation syndrome, patients with Chronic Obstructive Pulmonary Disease, dyspnea, field measures of panic, pregnancy, childbirth and the postpartum period, as well as the premenstrual syndrome afford pointed opportunities, new information and potential tests of the theory. A recent challenge to the theory from acetazolamide infusion is discussed. Developing a possible antecedent for the pathologically depressed threshold for the suffocation alarm, in the form of a phasic endorphinergic deficiency, is presented.

Autonomic characteristics of nonclinical panic and blood phobia

Autonomic characteristics of nonclinical panic and blood phobia were compared using spectral analysis of the electrocardiogram (EKG), as well as more conventional cardiovascular measures. The cardiovascular responses of 11 subjects who reported recent occurrence of frequent severe panic attacks, and 10 subjects who reported intense somatic reactions to the sight of blood (including episodes of syncope) were recorded during a variety of laboratory tasks (quiet rest, reaction time/shock avoidance, face immersion, and combined reaction time/face immersion). Results suggest distinct autonomic patterns in the groups. Panickers showed (a) higher heart rate and reduced heart-rate variability (b) aberrant associations among cardiovascular measures, and (c) dominant sympathetic control of heart rate coupled with diminished vagal tone. Blood phobics generally displayed an opposite pattern. The relevance of these findings to the etiology of panic and blood phobia, as well as to biological models of anxiety disorders in general, is discussed.

Cardiac vagal tone in generalised anxiety disorder

The aim of the present study was twofold: firstly, to determine cardiac vagal tone in subjects with generalised anxiety disorder directly, using an invasive pharmacological method; and secondly, to test whether the non-invasive method of measuring the amplitude of respiratory sinus arrhythmia (RSA) gives a reliable estimate of cardiac vagal tone in this form of anxiety disorder. Comparison of baseline physiological measures of anxious and control subjects revealed that cardiac vagal tone and heart rate were not different in the two groups of subjects, whereas length of the respiratory cycle and amplitude of respiratory sinus arrhythmia were reduced in the former group. Because of the higher respiratory rates of anxious subjects, the RSA method was found to underestimate cardiac vagal tone in generalised anxiety disorder.

Attention and memory for threat in panic disorder

Recently, information processing paradigms have been utilized to explore the role of attentional and memory processes in the maintenance of clinical anxiety disorders. The present study extended these data using a dual-task paradigm to assess attentional vigilance and a cued recognition task to evaluate short-term memory effects in Panic Disorder (PD). Twenty PD patients and 20 normal controls completed a computerized task wherein they read aloud one of a pair of rapidly presented words (primary task) while simultaneously attempting to detect a small probe that appeared adjacent to one of the words (secondary task). Eighty stimulus words were chosen to represent four categories: physical panic-related threat, social threat, positive-emotional, and neutral. Reaction time and accuracy in detecting the probe were assessed, as well as psychophysiological responding (heart rate, skin conductance, EMG). Following task completion, a cued recognition task was administered to examine short-term memory of task stimuli. Results indicated that PD patients exhibited slower reaction times relative to normal controls during presentation of physical panic-related threat and positive-emotional stimuli. A similar trend emerged for social threat stimuli, although the PD and control samples responded similarly to neutral stimuli. No group differences were found on the cued recognition measure or psychophysiological responding during task performance. The data are discussed in terms of possible implications for cognitive models of PD.

Continuous physiological changes and subjective reports in panic patients: a preliminary methodological report

Six panic disorder patients and six matched control subjects were studied using a new technique allowing continuous and simultaneous monitoring of physiological responses (blood pressure, heart rate, respiration) and subjective reports of anxiety and panic. This was done before, during, and after CO2 inhalation. Panic patients had significantly higher variability in their heart rate, blood pressure, and breathing rate than the control subjects. They also had irregular breathing patterns with frequent pauses. We identified three different patterns of response to CO2 inhalation in the panic patients. Some patients who panicked on CO2 showed a definite association between changes in physiological responses that preceded their subjective ratings of anxiety; however, others did not show this pattern. The possibility of different physiological mechanisms of panic in different patients is discussed.

General activity in baboons measured with a computerized, lightweight piezoelectric motion sensor: effects of drugs

A small, 1-oz activity-monitoring device is described for measuring motor activity continuously for periods of up to 42 days. The monitor employs a piezoelectric sensor that detects extremely small accelerations induced by movements. The monitor can be placed on collars or harnesses (e.g., for rabbits, cats, dogs, nonhuman primates, etc.). The use of the monitor is described within numerous laboratories studying the behavioral pharmacology of drugs in individually caged laboratory baboons. Patterns of daily activity were reliably recorded over periods of several months, and reflected the normal activity patterns of animals. The activity monitor recorded reliable, drug-induced changes in general activity that paralleled the known effects of the same drugs on learned behaviors. Low doses of the stimulants cocaine and d-amphetamine both increased general activity. Marked reductions in general activity were observed following both the administration of delta-9-tetrahydrocannabinol and an antihypertensive drug combination of diuretic and verapamil.

Panic disorder. Recognizing and managing the 'real thing'

Panic disorder is a severe anxiety disease frequently encountered in primary care. Although it is associated with potentially serious medical and psychiatric complications and is often difficult to diagnose, the condition is highly treatable. Initial pharmacotherapy may include alprazolam (Xanax), imipramine hydrochloride (Janimine, Tofranil), or phenelzine (Nardil). Correct diagnosis and treatment can alleviate much suffering and expense and promote both mental and physical health.

Psychological precursors of panic attacks

The ongoing experience of panic disorder was assessed in 20 female subjects, to determine psychological precursors to panic attacks. Measures of anxiety, threat, control, prediction of panic, and symptoms were assessed at hourly intervals during waking hours for one week. Measures were taken using a portable computerised diary which prompted for and stored responses. Patients' ratings of the prediction of panic attacks were the only significant precursors to panic attacks. This supports recent research that expectancy is important in panic onset. The data also suggested that anxiety levels follow a circadian pattern.

Anxiogenic properties of yohimbine. II. Influence of experimental set and setting

To study the pharmacological induction of stress along with psychological stress and their possible interaction, 20 mg yohimbine and placebo orally were administered to 8 panic patients on placebo treatment, 7 panic patients on alprazolam treatment and 12 controls in a double-blind crossover design. Two structured situations which can be considered as 'neutral' stressors were included: a mental arithmetic task and a continuous performance task. Mental arithmetic induced robust increases in ratings of panicky, anxiety, nervousness, heart rate and electrodermal activity, while the continuous performance task induced increases exclusively in skin conductance reaction. Patients responded to these tasks less than controls with regard to subjective ratings and electrodermal activity. Yohimbine did not potentiate the response to the tasks in the patients. In controls, heart rate during the mental arithmetic task, but not during rest, was increased after yohimbine. In contrast to other yohimbine challenge studies no panic attacks were observed. It is hypothesized that the experimental design together with an instructional set that reduces expectancy factors and the inclusion of structured and time-limited tasks in a challenge paradigm is able to reduce the anxiogenic effects of yohimbine.

Reducing heart rate reactivity to stress with feedback. Generalization across task and time

Heart rate (HR) reactions to two behavioral stressors (videogame and mental arithmetic) were measured in 8 experimental subjects who received biofeedback training and 8 matched control subjects during three assessment periods: pretraining, posttraining, and one-week follow-up. Experimental subjects exhibited significant reductions in HR following a training session in which they received ongoing HR feedback while playing a videogame. Control subjects, who played the same number of videogames without HR feedback, showed smaller HR reductions. During the training session, all subjects were instructed to reduce HR while maximizing game performance. In comparison to controls, experimental subjects (a) maintained lower HRs during videogame presentations after a one-week period and (b) generalized these HR reductions to the mental arithmetic challenge at follow-up. Performance on the videogame declined from posttraining to follow-up for experimental subjects but not for control subjects. No group difference in mental arithmetic performance was observed.

A prospective study of panic and anxiety in agoraphobia with panic disorder

The features of panic and anxiety in the natural environment were studied by prospective self-monitoring in 39 patients with chronic agoraphobia and panic disorder. Panics overlapped greatly with anxiety episodes but were more intense. Panics occurred more often in public places than did anxiety episodes, but had otherwise similar symptom profile, time of occurrence, and antecedents. Most panics surged out of a pre-existing plateau of tonic anxiety which lasted most of the day. Spontaneous panics were less frequent than situational panics and occurred more often at home but were otherwise similar. These findings do not support the sharp distinction between panic and anxiety in DSM-III-R, not its emphasis on spontaneous panic in classifying anxiety disorders. Thoughts of dying and 'going crazy'/losing control accompanied only a minority of panic/anxiety episodes and seemed to be a product of intense panic rather than a cause.

Characteristics of panic attack subtypes: assessment of spontaneous panic, situational panic, sleep panic, and limited symptom attacks

We report the analyses of daily journal descriptions of 790 self-defined panic attacks from 59 patients meeting DSM-III criteria for panic disorder or agoraphobia with panic attacks. The DSM-III-R specified symptoms occurred with frequencies ranging from choking (17% of attacks) to palpitations (63% of attacks). The mean weekly panic attack severity correlated significantly with the number of symptoms per attack, but not their weekly frequency. Within a given person, situational and spontaneous panic attacks did not significantly differ over a number of characteristics, including severity, duration, frequency per week, diurnal distribution, and the number of symptoms per attack. Limited symptom attacks were less severe, but were otherwise similar to panic attacks. Also, panic attacks during sleep were less frequent than panic attacks in the awake state, but did not significantly differ on other descriptive characteristics. These data support the validity of the symptoms specified for panic attacks by DSM-III-R. They also suggest that within an individual, panic attacks of various subtypes may be descriptively similar, despite the differing contexts in which they arise. In addition, these data question the diagnostic significance of the limited symptom attack-panic attack distinction.

Psychophysiological response patterns in panic disorder

To determine whether panic disorder patients exhibit physiological hyperarousal during rest or during mild, non-panic-inducing stress, 18 patients who experienced frequent panic attacks were compared with nonanxious controls on a battery of physiological assessments. During baseline, patients with panic disorder exhibited higher forehead electromyographic activity, higher systolic blood pressure and higher heart rates than non-anxious volunteers. During psychological stress, heart rate and systolic blood pressure rose more in patients with panic disorder than in nonanxious controls. The skin conductance response, however, was greater and more variable in the nonanxious controls. The results suggest that panic disorder patients with frequent panic attacks exhibit heightened cardiovascular arousal and decreased electrodermal flexibility than nonanxious people, even in nonthreatening situations.

Treatment effects of alprazolam and imipramine: physiological versus subjective changes in patients with generalized anxiety disorder

The correspondence between changes in physiological activity and somatic symptom reports was assessed in generalized anxiety disorder patients treated with alprazolam or imipramine. After 6 weeks, the two medications produced comparable reductions in self-reported somatic symptoms. However, patients taking alprazolam showed decreases in systolic blood pressure, epinephrine, and norepinephrine, and patients taking imipramine showed increases in heart rate, blood pressure, electromyographic activity, and norepinephrine. Thus, though the physiological changes associated with alprazolam treatment were consistent with changes in symptom reports, treatment with imipramine produced a desynchrony: patients reported significant decreases in cardiovascular symptoms and muscle tension in spite of the fact that heart rate, blood pressure, and electromyographic activity increased. Possible explanations for this counterintuitive phenomenon are discussed.

Adrenergic status in anxiety disorders: platelet alpha 2-adrenergic receptor binding, blood pressure, pulse, and plasma catecholamines in panic and generalized anxiety disorder patients and in normal subjects

In order to evaluate adrenergic function in anxiety disorders, platelet alpha 2-adrenergic binding parameters and supine and standing blood pressure, pulse, and venous plasma epinephrine and norepinephrine were determined in patients with panic attacks or generalized anxiety disorder and in normal subjects. The maximum number of binding sites (Bmax) for the partial agonist tritiated clonidine was significantly lower for both patient groups than for normal subjects, and the Bmax for the antagonist tritiated yohimbine was significantly lower for panic patients. There were no other substantive differences across groups. Prior exposure to psychotropic drugs might account for the results for clonidine binding, but not for yohimbine. The Bmax for clonidine was correlated with norepinephrine increases upon standing and, for panic patients, with the severity of full unexpected panic attacks. These data provide further evidence of adrenergic receptor abnormalities in people with anxiety disorders.

Motor activity and tonic heart rate in panic disorder

Motor activity and tonic heart rate were monitored in 62 drug-free panic disorder patients and 40 normal control subjects. Mean daily activity, mean waking heart rate controlled for activity, and mean sleeping heart rate were determined. Panic disorder patients without phobic avoidance showed higher activity than control subjects or patients with limited or extensive avoidance. Similarly, an "inverted U", relationship between trait anxiety and activity was observed. On the other hand, neither mean waking nor sleeping heart rate showed significant differences between patients and controls, suggesting that the differences previously reported in laboratory studies result from anticipatory anxiety.

The use of a real-time computer diary for data acquisition and processing

Behavioural researchers have long relied on the use of diaries for the collection of self-report data. We discuss the characteristics of a programmable hand-held computer used to collect hourly and event generated data for 7 days on 20 subjects with panic disorder. In the application described, subjects answered a series of 19 or more questions on the hour from 0700 to 2300 or when they were having a panic attack. Subjects completed 88% of all the hourly ratings (range 64-98%). The system was well accepted by the subjects and provided relatively inexpensive data collection and management.

Cardiovascular considerations in selection of anti-panic pharmacotherapy

Patients with panic disorder may be at increased risk for cardiovascular morbidity and mortality. There is also preliminary evidence that some cardiovascular risk factors may be increased in patients with panic disorder. Since anti-panic medications can alter cardiovascular function, the cardiovascular effect of these medications should be considered, particularly when used in patients with cardiovascular disease. This article will review the cardiovascular side effects of anti-panic medications.

Symptom reporting during voluntary hyperventilation and mental load: implications for diagnosing hyperventilation syndrome

Hyperventilation is considered an important factor in the production of a variety of somatic symptoms. This complex of symptoms is called the Hyperventilation Syndrome (HVS). Recognition of symptoms during the hyperventilation provocation test (HVPT) is a widely used criterion for diagnosing HVS. The validity of this criterion is tested in the present study. Twenty-three patients suspected of HVS performed a HVPT (hyperventilation during 3 min) and a mental load task (Stroop Color Word Test; CWT). It appeared that about the same number of patients (61%) recognized symptoms during the HVPT as during the CWT (52%), despite severe hypocapnia in the first test and normocapnia in the second. Reporting of symptoms was significantly related to psychological state and trait measures (SCL-90 and STAI scores) and unrelated to the degree of hypocapnia. These data have far reaching consequences, as they not only undermine the validity of the HVPT, but also question the tenability of the concept of HVS.

Biological correlates of lactate sensitivity in panic disorder

In this pilot study, 9/9 patients with panic disorder experienced a lactate-induced panic attack as compared with 0/9 controls. Baseline measurements were significant for higher anxiety self-ratings, higher heart and respiratory rates, elevated potassium, and lower lymphocyte 3H-dihydroalprenolol (DHA) binding in the patient group. Spielberger State anxiety scores correlated with baseline mean heart rate, and Spielberger Trait anxiety scores with lymphocyte DHA binding. The lactate infusion was not found to differentially affect any physiological or biochemical measures in the two groups, though heart rate surges occurred in most patients. Intravenous propranolol reduced the panic to a negligible degree, whereas intravenous diazepam was quite effective. Neurobiological implications are discussed, and the contradictory biological findings in the lactate literature are reviewed.

An appraisal of the DSM-III system

DSM-III is a major document in the history of psychiatry. The DSM-III system is here seen as an instrument that promotes the scientific development of psychiatry and the clarity of communication among psychiatrists. However a major theme of this review is that reliability does not ensure validity. While making this point it is recognized that the major defects in the DSM-III system result from scientific inadequacies inherent in present day psychiatry. This review also may be taken as an amplification of the statement in DSM-III-R that it is not a textbook. In particular the data required to arrive at diagnoses in the DSM-III system do not provide sufficient information to arrive at a comprehensive biopsychosocial case formulation, a shortcoming that has relevance for teaching and clinical practice.

Differential reactivity to lactate infusions: the relative role of biological, psychological, and conditioning variables

Nine patients with panic disorder experienced a lactate-induced panic attack, whereas nine controls did not. Higher preinfusion anxiety levels and heart rates were associated with panic disorder, and high baseline anxiety ratings were associated with atypical, severe lactate-induced panic attacks. Nevertheless, it was difficult to reconcile patients' and controls' reactivity to lactate as entirely secondary to baseline differences. Subjects differed qualitatively in the types of specific symptoms experienced and quantitatively in their anxiety and heart rate responses. In most cases, panic began with various central perceptual changes; peripheral cardiovascular and autonomic symptoms followed later. No patient rated a lactate-induced panic attack as identical to a naturally occurring attack. Not only did specific symptoms differ in their severity and order of production, but lactate-induced panic lacked the typical fears of dying, going crazy, or losing control. The results suggest that though environmental effects, expectancy biases, and baseline psychological states play salient roles in modifying the experience of a lactate-induced panic attack, they do not fully account for lactate sensitivity. The relative role that biological, psychological, and conditioning factors play in lactate-induced panic is discussed.

Dyspneic-fear and catastrophic cognitions in hyperventilatory panic attacks

The tenability of cognitive explanations of the experience of fear during panic attacks (viz. Ley's misattribution-of-symptoms hypothesis and Beck's and Clark's catastrophic-misinterpretation-of-symptoms hypotheses) is seriously questioned by findings from three independent lines of research: (a) Wolpe and Rowan's observation that catastrophic cognitions follow fear, (b) Rachman, Levitt and Lopatka's reports of panic attacks without fearful cognitions, and (c) reports of panic attacks during sleep occurring predominately during non-dreaming stages of sleep. Recognition of these findings led Ley to reject his misattribution-of-symptoms hypothesis in favor of an innate emotional-respiratory-response explanation. The revised hyperventilation theory now maintains that fear experienced during a hyperventilatory panic attack is caused by severe dyspnea in the context of little or no perceived control over the causes of the dyspnea (i.e. dyspneic-fear). Cognitions during panic attacks are discussed in terms of the cognitive deficit that results from the cerebral hypoxia produced by hyperventilation. Implications for theory and treatment are discussed.

Factors influencing drinking behavior in alcoholic panickers and non-panickers

Male alcoholics who (a) experienced panic attacks prior to abusing alcohol, (b) experienced panic attacks subsequent to abusing alcohol, and (c) had not experienced panic attacks were compared on three sets of measures: the Panic Attack Questionnaire, the Restrained Drinking Scale, and the Inventory of Drinking Situations. The results showed that two groups of Ss who experienced panic attacks were more likely than non-panickers to use drugs other than alcohol, began drinking at an earlier age, had a greater proportion of parents with panic and alcohol related problems, had higher drinking restraint scores, and drank in more situations. The Ss who experienced panic attacks prior to abusing alcohol were more likely than the other groups to drink in situations similar to those related to agoraphobic fears. It was postulated that alcoholics who experience panic attacks, especially those who experienced panic attacks prior to abusing alcohol may be using alcohol to reduce anxiety or fear related to panic attacks.

Panic attacks during relaxation and relaxation-induced anxiety: a hyperventilation interpretation

This paper explains how a hyperventilation theory of panic disorder accounts for panic attacks during relaxation and relaxation-induced anxiety. The explanation is based on the observation that chronic hyperventilators maintain a steady state of low pCO2 (arterial carbon dioxide tension) and are, therefore, sensitive to relatively small increases in ventilation when metabolism is low and to relatively sudden reductions in metabolism when ventilation is relatively constant. Thus, if minute volume of air breathed remains constant while the metabolic production of CO2 decreases, as in the case of one who sits down or lies down to relax, respiratory hypocapnea may increase in intensity until it produces the familiar sensations which mark the panic attack. Data from relevant studies of panic attacks during relaxation support the hyperventilation interpretation.

Panic attacks during sleep: a hyperventilation-probability model

Panic attacks during sleep are analysed in terms of a hyperventilation theory of panic disorder. The theory assumes that panic attacks during sleep are a manifestation of severe chronic hyperventilation, a dysfunctional state in which renal compensation has led to a relatively steady state of diminished bicarbonate. Reductions in respiration during deep non-REM sleep lead to respiratory acidosis which triggers hyperventilatory hypocapnea and subsequent panic. A probability model designed to predict when during sleep panic attacks are likely to occur is supported by relevant data from studies of sleep and panic attacks. Implications for treatment are discussed.

Biology of anxiety

Our understanding of the biological basis of anxiety is far from complete, although our knowledge of both the neuropharmacologic and molecular basis of anxiety has increased. This article reviews our current knowledge of the possible biological basis of generalized anxiety disorder and panic disorder.

Systemic hormonal and physiological abnormalities in anxiety disorders

Among the studies of systemic hormonal and physiological abnormalities associated with anxiety disorders, the most consistent and extensive findings suggest (a) peripheral adrenergic hyperactivity (including increases in norepinephrine but not epinephrine) and functional dysregulation, (b) increased incidence of mitral valve prolapse in panic patients, and (c) normal suppressibility of the hypothalamic-pituitary-adrenal cortical endocrine system with dexamethasone in panic patients. Other less-certain findings include (a) increased circulating concentrations of plasma ACTH and/or cortisol, and prolactin, in panic patients, (b) increased platelet monoamine oxidase activity in generalized anxiety and/or panic patients, (c) decreased gonadal axis activity in some anxious individuals, (d) decreased nighttime melatonin plasma concentrations in panic patients, and (e) peripheral alpha 2 and beta-adrenoreceptor down-regulation, with normal serotonin binding parameters. These findings, taken together, provide tentative support for dysfunction in adrenergic and GABAergic central nervous system mechanisms in people with anxiety disorders. Abnormal anxiety and normal stress both show evidence of adrenergic hyperactivity; however, there appear to be differences in hormonal profiles, especially the apparent lack of increase of epinephrine during panic attacks, as well as differences in the reactivity of the system, and in the "trigger" mechanisms which determine when the response occurs.

Neuropsychophysiological correlates of lactate-induced panic

1. One of the simplest and most direct applications of neuropsychophysiological techniques is to anxiety disorders. 2. The physiological changes accompanying the lactate induction of panic appear, for most response systems, to be similar to those found spontaneously in anxious patients and are characteristic of a state of hyperarousal. 3. Patients vulnerable to lactate-induced panic exhibit higher than normal pre-panic autonomic activity, elevated autonomic-somatic activity during lactate-induced panic and an EEG response to provoked panic which appears to be comprised of a "paradoxical" shift towards slow wave delta activity and an altered brainstem evoked response. 4. Additional studies are warranted to determine the relationship of these physiological changes to the triggering of panic and preliminary attempts in this direction are discussed.

Unrecognized prevalence of panic disorder in primary care, internal medicine and cardiology

Research over the last 25 years has delineated the syndrome of panic disorder/agoraphobia from a myriad of medical, cardiologic and psychiatric diagnoses. This syndrome is characterized by the sudden onset of episodes of panic and terror, accompanied by extreme physiologic symptoms including palpitations, tachycardia, chest pain, shortness of breath, trembling, faintness, etc. These patients become quite anxious and hypochondriacal and begin to avoid certain situations in which they feel a recurrence of a panic attack would be dangerous or embarrassing. This avoidance (agoraphobia) typically involves malls, grocery stores, churches, crowds, bridges, planes, waiting in lines, visiting dentists, highways, etc., and rarely (5%) actually confines the patient to his home. With the prevalence of 3 to 7% in the general population, evidence suggests that many of these patients are currently unrecognized in primary care, internal medicine and cardiology practices. Over 90% believe they have a physical disorder and do not present to psychiatrists but instead to neurologists (44%), cardiologists (39%) and gastroenterologists (33%). Perhaps as many as one-third of patients with atypical chest pain, particularly if results of coronary angiograms are normal, have unrecognized panic disorder. Effective treatments in most patients are now available and are described. These include medications that block the panic attacks and reduce the anxiety and phobic fears and they are generally used in combination with behavioral treatments.