Bert Garssen

Agoraphobia and the hyperventilation syndrome

Abstract One of the causes of agoraphobic complaints is the fear of having an attack of physical complaints in public places. The Hyperventilation Syndrome (HVS) with its diverse symptoms seems to fit well in this model. Hyperventilation symptoms are threatening, because for most subjects they occur unexpectedly and without a clear reason. An investigation was made into how often the HVS and the agoraphobic syndrome appeared together and into the causal relationship between both syndromes. About 60% of the agoraphobic patients suffered from hyperventilation complaints and about 60% of the HVS patients were agoraphobic. Most patients mentioned the fear of having an attack as an important reason for their agoraphobic complaints, and this applied especially in the case of the HVS.

Comorbidity among the anxiety disorders

This paper reports on the diagnoses of 120 consecutive referrals to an outpatient research program on anxiety disorders. Patients were diagnosed according to DSM-III-R criteria using a structured interview. Patterns of comorbidity among disorders were examined using two diagnostic procedures. One procedure was based on the temporal sequence of disorders, the other on the relative interference with patient functioning. The two procedures rendered different findings, with simple and social phobia more often assigned as primary diagnosis in the temporal procedure, and panic disorder with agoraphobia most often assigned as primary interference diagnosis. Comparison of comorbidity patterns for panic disorders patients with findings from an American sample revealed no significant differences. Findings from this study are discussed in terms of their implications for assessment and research. It is suggested that the diagnostic criteria for simple phobia are somewhat problematic.

Breathing retraining, exposure and a combination of both, in the treatment of panic disorder with agoraphobia

The present study investigates the differential effectiveness of three treatment packages for agoraphobia. Patients suffering from panic disorder with agoraphobia (DSM-III-R) received one of three treatments: Breathing Retraining with Cognitive Restructuring (BRCR), graded self-exposure in vivo (EXP), or a combination of BRCR and EXP. Treatments consisted of 8 sessions. Assessment consisted of self-report measures for panic, phobic anxiety and avoidance, depression, general anxiety, somatic complaints and fear of body sensations, and of two respiratory measures (respiratory rate and alveolar pCO2). The treatments resulted in a reduction in symptomatology on all self-report measures, except panic frequency, and in a decrease in respiratory rate. There was no evidence for a differential efficacy for any of the treatments on any of the variables. Contrary to expectation, and at odds with findings from earlier studies, BRCR had no significant effect on panic frequency. A detailed comparison of sample characteristics of patients in our study and previous studies, did not yield insight into possible causes for the failure to replicate earlier results. The limited effectiveness of breathing retraining in reducing panic, as observed in the present study, leads us to conclude that the role of hyperventilation in panic is less important than previously thought.

Breathing retraining: A rational placebo?

Breathing retraining of patients with Hyperventilation Syndrome (HVS) and/or panic disorder is discussed to evaluate its clinical effectiveness and to examine the mechanism that mediates its effect. In relation to this theoretical question, the validity of HVS as a scientific model is discussed and is deemed insufficient. It is concluded that breathing retraining and related procedures are therapeutically effective, but probably due to principles other than originally proposed, namely decreasing the tendency to hyperventilate. An alternative principle is the induction of a relaxation response, presenting a credible explanation for the threatening symptoms, giving a distracting task to practice when panic may occur, and promoting a feeling of control.

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.

Voluntary hyperventilation: the influence of duration and depth on the development of symptoms

Hyperventilation is considered an important factor in the development of somatic symptoms or even panic attacks, though its role has recently been disputed. Arguments are often based on findings from the so-called Hyperventilation Provocation Test (HVPT), which is a procedure consisting of voluntarily overbreathing. The HVPT has been widely used for diagnosing Hyperventilation Syndrome and for experimentally eliciting panic attacks. Almost no attention, however, has been paid to standardizing the test and determining critical values with respect to depth and duration of hyperventilation. In the present study, symptom development was examined in 16 healthy subjects who underwent four HVPTs that differed in depth of hyperventilation (end-tidal PCO2 < 2.4 kPa or < 1.9 kPa), as well as duration of hyperventilation (2 or 5 min). Both depth and duration appeared to have an independent effect on the development of symptoms. In the 5-min condition, symptoms appeared mainly within the first 3 min. To be sure that the HVPT is long enough and deep enough to elicit symptoms in most people, a minimum duration of 3 min is advised, with end-tidal PCO2 decreasing to at least 1.9 kPa or dropping well over 50% of baseline.

THE HYPERVENTILATION SYNDROME IN PANIC DISORDER, AGORAPHOBIA AND GENERALIZED ANXIETY DISORDER*

The symptom complex of panic disorder and generalized anxiety disorder suggests an etiological role for hyperventilation. The present study investigates the overlap between DSM-III-R panic disorder, panic disorder with agoraphobia and generalized anxiety disorder with hyperventilation syndrome (HVS). The anxiety disorder diagnoses were based on a structured interview, and HVS syndrome (HVS). The anxiety disorder diagnoses were based on a structured interview, and HVS determined by the so-called hyperventilation provocation test (a brief period of voluntary hyperventilation with recognition of symptoms). The overlap rates with HVS were: 48% for panic disorder, 83% for panic disorder with agoraphobia and 82% for generalized anxiety disorder. However, a pilot study on transcutaneous monitoring of carbon dioxide tension leads us to question the validity of the voluntary hyperventilation method that we used to determine HVS-status. It is unclear whether hyperventilation plays an important role in panic and general anxiety, as our overlap findings suggest. For patients who recognize the symptoms induced by voluntary hyperventilation, the hyperventilation provocation procedure provides a therapeutic means of exposure to feared bodily sensations.

Clinical Aspects and Treatment of the Hyperventilation Syndrome

The Hyperventilation Syndrome is a common disorder and clinical psychologists will be regularly confronted with it, because the syndrome is closely interwoven with psychological problems. The literature is reviewed with respect to pathophysiology of the complaints, aetiology of the syndrome and treatment. A new developmental model is presented and directions for future research are proposed.

THE LOW SPECIFICITY OF THE HYPERVENTILATION PROVOCATION TEST

The Hyperventilation Provocation Test (HVPT) has become a routine procedure in the diagnosis of hyperventilation syndrome (HVS). During an HVPT the patient voluntarily overbreathes for several minutes to produce hypocapnia. The test is considered positive if the induced symptoms are recognized by the patient as similar to those experienced in daily life. The present study tests the assumption that hypocapnia is the primary trigger for symptoms during an HVPT. In a randomized double-blind crossover design. 115 patients suspected of HVS and 40 healthy controls performed an HVPT and a placebo test (PT, isocapnic overbreathing). The HVPT induced more symptoms than the PT, especially more neuromuscular symptoms, cerebral symptoms, paresthesias, and temperature sensations. However, the absolute difference between the number of symptoms induced by the HVPT and PT was small. In patients, the PT induced 66% of symptoms induced by the HVPT. In the control group this percentage was 60%. The low specificity of the HVPT implies that symptom recognition during the HVPT is invalid as a diagnostic criterion for HVS.

A follow-up study on short-term treatment of agoraphobia

The differential effectiveness of three treatment packages for agoraphobia was tested. Patients received one of three short-term treatments: Breathing Retraining and Cognitive Restructuring, graded Self-Exposure in vivo, or a combination of both. No differential effects were found between the treatment conditions at posttest and at an 18 months follow-up. Improvement at follow-up assessment was associated with whether patients had further treatment during the follow-up period. No relationship was found between further improvement and demographic variables, pre- and posttest scores on psychological questionnaires or the use of medication at follow-up. Implications of these findings are examined.