Vasopressin response to lactate infusion in normals and patients with panic disorder

Infusions of sodium lactate evoke panic symptoms in patients with panic disorder but not in normal subjects. Although plasma vasopressin (AVP) is known to rise in response to other forms of stress, its response during this maneuver has not previously been reported. We measured plasma AVP in double-blind infusions of sodium lactate in 5 normal subjects, 6 patients with panic disorder, and, again in 4 patients after chronic alprazolam. In all groups administered lactate, AVP rose significantly above baseline values (p less than 0.05) though no change was seen in a control group of patients during D5NS infusion. No difference in AVP response to lactate was apparent between untreated patients (who experienced panic) and normals or chronically treated patients (who had minimal symptoms). Thus, the presence of panic symptoms induced by lactate is insufficient to provoke an abnormal pattern of AVP release.

Neuroendocrine correlates of lactate-induced anxiety and their response to chronic alprazolam therapy

Lactate infusions are anxiogenic in patients with panic disorder or agoraphobia with panic attacks, but few neuroendocrine profiles of this effect have appeared. The authors measured the number and intensity of panic symptoms and blood hormone levels during double-blind lactate infusions in 25 patients and 10 normal subjects and during placebo infusions in another five patients. Each patient was rechallenged with an identical infusate after chronic double-blind outpatient treatment with alprazolam or placebo. The results confirm the effectiveness of lactate infusions in evoking anxiety, extend previous hormone profiles of this maneuver, and indicate that chronic alprazolam treatment minimizes the neuroendocrine response to lactate challenges in patients with panic disorder or agoraphobia with panic attacks.

Thyroid indices in panic disorder

Eighty-two patients suffering from panic attacks with or without phobias were examined for evidence of thyroid disease. None of the patients had abnormal total T4 or T3 resin uptake measurements, regardless of whether they were nonmedicated or treated with one of three antipanic drugs: alprazolam, phenelzine, or imipramine. A higher than expected incidence of undetectable TSH levels (22% overall) appeared in all groups. The clinical relevance of this finding is currently uncertain.

Lactate infusion in anxiety research: its evolution and practice

The unpredictability of spontaneous unexpected panic attacks has inhibited the controlled study of this phenomenon. Previous studies demonstrated that an increase in blood lactic acid occurred concomitant with symptoms of anxiety in anxiety-prone patients who underwent standard physical exercise. The question of whether these patients had an excessive sensitivity to lactate led to the development of the lactate infusion model, in which anxiety is induced in a controlled environment. The history and current application of the lactate infusion model in the study of neurochemical correlates of panic are described, and a methodology for lactate infusion procedures is outlined.

Monoamine oxidase inhibitors and alprazolam in the treatment of panic disorder and agoraphobia

This article reviews the evidence on the efficacy of monoamine oxidase inhibitors (MAOIs) and of alprazolam in the treatment of panic disorder and agoraphobia. It also presents guidelines to the clinician on how to implement these treatments in practice.

Panic anxiety: a new biological model

Previously unrecognized similarities among metabolic responses to various maneuvers used to evoke anxiety in patients with panic disorder are described. On the basis of these observations, a new biological model is proposed for panic disorder, in which the primary defect--which is neuroendocrine rather than psychiatric--is operationally placed within the redox-regulating apparatus of the brain stem. This model is consistent with many clinical features of panic disorder and also provides a theoretical framework for further studies of the pathophysiology of this and related conditions (e.g., hyperventilation syndrome).

Delineation of anxiety and phobic disorders responsive to monoamine oxidase inhibitors: implications for classification

Studies of the treatment of panic anxiety and various other states with monoamine oxidase (MAO) inhibitors are critically reviewed. It is concluded that MAOIs have differential effects on several dimensions of pathologic anxiety. The association between depression and anxiety states is also reviewed; it is observed that MAOIs effectively treat severe anxiety and phobic disorders without operating strictly via their antidepressant mechanism. In addition, it is proposed that biologic depression and biologic anxiety should be considered to have some independence from one another. Guidelines for the clinical delineation of anxiety disorders are provided, and the clinical and research implications of the proposal for revision of DSM-III anxiety and phobic disorders section, are outlined in detail. It is suggested that anxiety and phobic disorders be classified into endogenous (disease) and exogenous (nondisease) types.

Some biochemical correlates of panic attacks with agoraphobia and their response to a new treatment

Thirty-two patients with chronic debilitating agoraphobia and panic attacks participated in a comparative study of the triazolobenzodiazepine alprazolam and the anti-inflammatory agent ibuprofen. After a 2-week placebo washout period, patients were randomly assigned to 8 weeks of treatment with alprazolam (2 to 6 mg/day) or ibuprofen (0.8 to 2.4 g/day). Medication was identically packaged and patients were blind to the treatment condition, but investigators were aware of which medication was dispensed. Alprazolam recipients (mean daily dose: 5.4 mg) improved markedly with respect to physician and patient global rating of disease severity, frequency and severity of panic attacks, and phobic anxiety target symptoms on the 90-Item Hopkins Symptom Check List. Ibuprofen recipients (mean daily dose: 2.13 g) experienced significantly less clinical improvement than patients on alprazolam. After 8 weeks of treatment, ibuprofen patients were crossed over to alprazolam, while the original alprazolam group continued on that drug. The daily dosage ceiling was increased to 10 mg. In the ensuing 4 weeks (mean daily alprazolam dose: 6.3 mg), all patients achieved comparably marked clinical improvement relative to baseline. Pretreatment plasma concentrations of platelet factor 4 and beta-thromboglobulin--two measures of platelet turnover and release--were significantly elevated in patients relative to normal controls. The elevated platelet factor 4 and beta-thromboglobulin normalized during treatment with both drugs. Alprazolam appears to produce rapid and specific clinical improvement in patients with severe agoraphobia and panic attacks and deserves further evaluation under double-blind conditions.

Panic attacks and the dexamethasone suppression test

Of 51 patients with panic attacks, 11.8% (7.8% with a correction factor) had a positive dexamethasone suppression test. This is significantly lower than the rate for melancholia. This difference suggests that panic attacks and major depression may be associated with different biological mechanisms.

Panic disorder in genotypic HLA identical sibling pairs

The authors describe two HLA identical sibling pairs with panic disorder. To their knowledge, this is the first report of histocompatibility testing in patients with anxiety disorders.

The diagnosis and drug treatment of anxiety disorders

Anxiety, phobic and related neurotic disorders lend themselves to diagnostic confusion because of the large and variable array of symptoms associated with them. This has complicated attempts at coherent classification. This paper examines the problems in diagnosis and classification and the diversity of causal models of these disorders. It offers an alternative integrated perspective that may have heurestic merit in guiding clinicians to a practical choice of treatment and in delineating a useful starting point for the biological investigation of these disorders.

The classification of anxiety and hysterical states. Part II. Toward a more heuristic classification

In the historical review and empirical delineation of the classification of anxiety and hysterical states (Part I), it was concluded that the existing classifications are unsatisfactory and require some reconceptualization if they are to be useful clinically and empirically. In keeping with more recent developments in the genetic, behavioral, pharmacological, biochemical, and psychophysiological investigation of these disorders, a new classification is proposed. The two major categories of anxiety and hysterical disorders have a different clinical presentation and course, a different mean age of onset, distribution of age of onset, sex distribution, response to treatment modalities, and habituation response on galvanic skin response. Empirical evidence supporting this proposal is cited. This classification has heuristic merit in guiding research efforts and discussions and in directing clinicians to a simple and practical solution to their patients' anxiety disorders.

The classification of anxiety and hysterical states. Part I. Historical review and empirical delineation

The history of the classification of anxiety, hysterical, and hypochondriacal disorders is reviewed. Problems in the ability of current classification schemes to predict, control, and describe the relationship between the symptoms and other phenomena are outlined. Existing classification schemes failed the first test of a good classification model--that of providing categories that are mutually exclusive. The independence of these diagnostic categories from each other does not appear to hold up on empirical testing. In the absence of inherently mutually exclusive categories, further empirical investigation of these classes is obstructed since statistically valid analysis of the nominal data and any useful multivariate analysis would be difficult if not impossible. It is concluded that the existing classifications are unsatisfactory and require some fundamental reconceptualization.

The classification of phobic disorders

The history of classification of phobic disorders is reviewed. Problems in the ability of current classification schemes to predict, control and describe the relationship between the symptoms and other phenomena are outlined. A new classification of phobic disorders is proposed based on the presence or absence of an endogenous anxiety syndrome with the phobias. The two categories of phobic disorder have a different clinical presentation and course, a different mean age of onset, distribution of age of onset, sex distribution, response to treatment modalities, GSR testing and habituation response. Empirical evidence supporting this proposal is cited. This classification has heuristic merit in guiding research efforts and discussions and in directing the clinician to a simple and practical solution of his patient's phobic disorder.

Psychosocial predictors of accident/error rates in nursing studies: a prospective study

A prospective study of accident/error rates was carried out on thirty-one nursing students. Recent life changes and stresses, social support available to cope with this stress, depression, illness rate, and coping skills were measured at baseline. Five weeks later students recorded accidents suffered and errors made over a week long period. The number of life changes in the previous two years made over a week long period. The number of life changes in the previous two years and the amount of adjustment required to cope with these changes, together with the social support available to help cope with these events were the most powerful predictors of accident/error rate. Together they accounted for 70 per cent of the variance. Multiple regression equations for the outcome variables were calculated to study the best linear predictor combination. Depression and coping skills had poor predictor power. The implications of the findings for health care personnel are discussed. Steps to lower the accident/error rate in those at risk are outlined.

Treatment of endogenous anxiety with phobic, hysterical, and hypochondriacal symptoms

Endogenous anxiety (anxiety hysteria, agoraphobia with panic attacks) is characterized by sudden, spontaneous panic attacks accompanied by multiple autonomic symptoms, overwhelming fear, a flight response, and polyphobic behavior. Psychotherapy, behavior therapy, and tranquillizers have been of limited success in treating this syndrome. Fifty-seven patients severely disabled by the syndrome for a mean period of 13 years completed the three-month study. Randomly assigned in a double-blind, placebo-controlled design to imipramine hydrochloride, pheneizine sulfate, or placebo, they were seen in supportive group therapy every two weeks. Patients in the pheneizine and imipramine cells showed significant improvement ovehe persistent trend for pheneizine to be superior to imipramine achieved significance only on the Work and Social Disability Scale and the Sympton Severity and Phobic Avoidance Scale. The implications for classification and theory are discussed.

Monoamine oxidase inhibitors: prescription and patient management

The historical roots of the current avoidance of MAOIs are reviewed. A practical approach to the careful prescription of MAOIs is outlined. Medical contraindications, side effects and their management and drug and food interactions with MAOIs are discussed. With careful patient selection, adequate caution by the physican, and appropriate preparation of the patient, MAOIs are often uniquely effective (as in endogenous anxiety) and have an acceptably low potential for serious toxicity.

The relationship between response qualities of life change events and future illness rates

A prospective study over three months explored whether measures of response "qualities" of life change events (e.g., whether the event was positive or negative in its subjective impact) enhance the ability of a simple counting of recent life change events to predict near future illness rates. Thirty-four nursing students were studied. Results confirm previous reports that future illness rates increase positively and significantly in direct relationship to the accumulation of recent past life change events. A simple count of the number of untimely or unexpected life stresses (31% of total life changes) or a simple count of the number of negative life events (53.8%) were as potent predictors as the total count of recent life changes. The total number of times each event occurred did not add to the predictive power of a count of the number of events experienced. Anticipated life events were poor predictors of future illness rates. The subjective life change unit scaling system (SLCU) did not add to the predictive power of a simple count of the number of events. Social support availability did not significantly lower illness rates.