Evidence for fear of restriction and fear of suffocation as components of claustrophobia

Abstract

Recent investigations of the aetiology and treatment of specific phobias have focussed on clarifying the concerns underlying phobic anxiety. It has been proposed that claustrophobic fear is comprised of separable confinement and suffocation components. This paper presents data from 78 general medical outpatients undergoing magnetic resonance imaging (MRI) scans in two major teaching hospitals. The findings support the two factor structure of claustrophobia, in that exposure to confinement reduced confinement subscale scores, but did not influence suffocation scores.

Introduction

Recent approaches to understanding claustrophobia have proposed that the fear is comprised of two separable components, fear of suffocation and fear of confinement (Rachman, 1997). Support for this view derives largely from factor analytic investigations of questionnaire responses. For example, Rachman and Taylor (1993)identified two separable rationally derived subscales from their claustrophobia questionnaire. Responses from a sample of university students subjected to a principal components analysis supported the existence of the two scales of the claustrophobia questionnaire. In addition, responses to behavioral tests concerned with confinement and suffocation confirmed the two factor structure. Similarly, Valentiner et al., (1996)developed a questionnaire to measure suffocation concerns and entrapment concerns. These authors used exploratory and confirmatory factor analyses of student responses to demonstrate the existence of scales predominantly reflecting entrapment and suffocation concerns.

The most direct evidence bearing on the separate contribution of fear of confinement and of suffocation to claustrophobic fears comes from demonstrations that procedures impacting on fear of confinement or suffocation alone reduce fear of confinement or suffocation respectively, but do not impact on the concerns that were not targeted. Such a methodology is proposed by Rachman (1997)for demonstrating the importance of suffocation concerns to claustrophobic fear. Arguably, successful completion of a MRI scan provides a powerful exposure to the experience of confinement without the possibility of suffocation. In contrast, most chambers used in the investigation of claustrophobic fear in the past have incorporated both restriction, in terms of size, and the possibility of suffocation, in that they are enclosed (e.g. Rachman & Levitt, 1988). Patients undergoing MRI scans lie inside a narrow cylindrical chamber. While the chamber is restrictive, dark and noisy, it is not sealed and patients can literally see the light at the end of the tunnel. Kilborn and Labbe (1990)examined fear reactions associated with MRI scans in a sample of 108 patients, 62 of whom provided information immediately before the scan and one month after the scan. Kilborn and Labbe reported scores from the Speilberger state-trait anxiety inventory (STAI) and the fear survey schedule (FSS) prior to the scan and at one month follow-up for those who (a) did and (b) did not complete the scan. Importantly for the present discussion, an examination of Kilborn and Labbe's results suggests that scores for state anxiety, FSS total and FSS item `enclosed places' increased from prescan levels to follow-up among people who failed to complete the scan but decreased among those who did complete the scan. Successful completion of the scan may be regarded as providing an exposure trial leading to reduced fear at follow-up.

The present study examines the impact of successful completion of a magnetic resonance imaging (MRI) scan on fear scores derived from Rachman and Taylor (1993)suffocation and confinement subscales. If fear of confinement and fear of suffocation are separable fears, it would be predicted that patients successfully completing MRI scans would show a decrease in their confinement scores in the absence of any change in suffocation scores.