Objective
Somatic causal illness attributions are being considered as potential positive criteria for somatoform disorders (SFDs) in DSM-V. The aim of this study was to investigate whether patients diagnosed with SFDs tend towards a predominantly somatic attribution style.
Methods
We compared the causal illness attributions of 48 SFD and 149 non-somatoform disorder patients, in a sample of patients presenting for an allergy diagnostic work-up, and those of 47 controls hospitalised for allergen-specific venom immunotherapy. The SFD diagnosis was established by means of the Structured Clinical Interview for DSM-IV. Both spontaneous and prompted causal illness attributions were recorded through interview and by means of the causal dimension of the Revised Illness Perception Questionnaire (IPQ-R), respectively. Patients' spontaneous and prompted responses were assigned to a psychosocial, somatic, or mixed attribution style.
Results
Both in the free-response task and in their responses to the IPQ-R, SFD patients were no more likely than their nonsomatoform counterparts to focus on somatic explanations for their symptoms. They were just as likely to make psychosocial or mixed causal attributions. However, patients with SFDs were significantly more likely to find fault with medical care in the past.
Conclusion
Our data do not support the use of somatic causal illness attributions as positive criteria for SFDs. They confirm the dynamic and multidimensional nature of causal illness attributions. Clinical implications of these findings are discussed.
In view of the forthcoming Diagnostic and Statistical Manual for Mental Disorders (DSM-V) and the International Classification of Diseases (ICD-11), there is an ongoing debate about the terminology and classification of somatoform disorders (SFDs) [1], [2], [3], [4] and [5]. There have been calls to move away from the ‘negative definition’ of SFDs as ‘medically unexplained’ towards a positive one, considering, among other things, somatic causal illness attributions as potential positive criteria [3], [5], [6], [7], [8], [9], [10], [11] and [12]. Since the early 1990s, causal illness attributions have been shown to influence the development, maintenance, and management of somatoform and functional somatic syndromes [3], [5], [13], [14], [15], [16], [17], [18], [19], [20], [21] and [22]. The ICD-10 already lists the adherence to somatic causal attributions as one of the main features of SFD patients [12]. However, empirical evidence of this assumption is relatively rare. Furthermore, variation in data collection methods and instruments, in data handling, and in the population studied certainly contributes to the heterogeneity of the findings (e.g., Refs. [23] and [24]): some studies support the notion of a tendency towards somatic illness attributions among SFD patients [25], [26], [27] and [28]. More recent studies and reviews [29], [30], [31], [32], [33], [34] and [35] and, in particular, qualitative studies on doctor–patient interaction [36], [37] and [38], however, present more of a mixed picture, with SFD patients being open to both somatic and psychosocial explanations of their symptoms.
Attribution theory and research have identified three main (exclusive) dimensions of causal attribution, namely, psychosocial, organic, and normalising [25], [39] and [40]. In addition, supporting the notion that illness attribution is a multidimensional process, with patients holding coexisting explanations for one and the same symptom or illness, factor analytic approaches based on the Illness Perception Questionnaire (IPQ) and its revised version (IPQ-R) have identified a number of attribution categories: psychological, risk factors, immunity, and chance factors [41], [42], [43], [44], [45] and [46]. Quantitative measures of illness attribution include lists of predetermined causal explanations from which patients can choose the one(s) closest to their own beliefs. This method assumes that the range of beliefs that are of interest are largely known [23]. On the contrary, qualitative studies allow patients to use concepts and categories that are relevant and meaningful to them. They have assessed attribution by simply asking patients what they attribute their symptoms to [19] and [32], by means of the more elaborate explanatory model interview [21] and [30], thematic content analysis of in-depth interviews [47], or transcripts of audiotaped consultations [36] and [37]. Similar to many of the quantitative studies, most of these analyses have focused on the dichotomy of psychosocial and somatic causal attributions.
The main purpose of this article was to assess the use of somatic causal attribution as a positive criterion of SFDs, with the long-term view to provide the basis for better diagnostic and therapeutic management. In particular, we aimed to test the hypothesis that SFD patients tend towards a predominantly somatic attribution style, combining and comparing both qualitative and quantitative research measures.
