The personality traits neuroticism and alexithymia have been hypothesized as predisposing factors for somatization. Stability over time is a basic assumption underlying any trait construct. Although there are considerable (and sometimes conflicting) data relevant to this issue, the stability of neuroticism and alexithymia has not been assessed in somatization. The main purpose of this study was to examine the temporal stability of neuroticism and alexithymia in patients presenting to their primary care physician with medically unexplained symptoms, and compare this to the stability of negative and positive affect, anxiety, and depression. A total number of 318 patients were assessed at baseline and at 6-months follow-up. Whereas the affective state dimensions changed significantly over the follow-up period, neuroticism and alexithymia were substantially stable.
A large number of factors have been studied to account for the phenomenon of somatization, including personality traits, considered to be risk factors for its development and persistence. One of them is neuroticism, defined as “a broad dimension of individual differences in the tendency to experience negative distressing emotions”1 (p. 301). Neuroticism has been repeatedly demonstrated to be related to somatization.1, 2, 3 and 4 Another trait dimension that has been hypothesized to play a role in the development of somatization, is alexithymia.5 This dimension, which literally means “no words for feelings,” is considered to reflect a deficit in the cognitive processing and regulation of emotions.6 The results of empirical research have demonstrated the existence of an association between alexithymia and somatization.7
Next to personality factors, the experience of psychological distress, especially anxiety and depression, has been considered to be an important factor in the development of somatization.8, 9 and 10 Empirical research has demonstrated a high degree of comorbidity between somatization, anxiety, and depression, both on a symptom and a syndrome level.11, 12 and 13 Despite the fact that anxiety and depression are closely related to positive as well as negative affect,14 the association between state positive affect and somatization has seldom been studied.15, 16 and 17
From a theoretical perspective, stability over time is a basic assumption underlying any trait construct, whereas measures of psychological distress are considered to be susceptible to changes in a person’s life situation and, as such, be state-dependent.18 and 19 From the literature it can be concluded that the stability of the personality trait neuroticism has been repeatedly confirmed, over shorter as well as longer periods of time, and measured with different questionnaires.1, 20 and 21 However, the large majority of study populations consisted of nonclinical subjects, especially students. Alexithymia was originally conceptualized as a stable personality trait, but was subsequently also defined as a state reaction, called secondary alexithymia.22 and 23 Although the stability of alexithymia has been established in nonclinical as well as clinical populations,24, 25, 26 and 27 its close association with depression,28 together with the fact that in some study samples alexithymia was found to lack temporal stability,29, 30 and 31 has led to the discussion whether alexithymia should primarily be defined as a stable personality trait or as a state-dependent measure that closely follows increases or decreases in level of psychological distress.29 and 32 To the best of my knowledge there are no data on the stability of neuroticism and alexithymia, as compared to dimensions of psychological distress, in somatization.
Somatization has been variously defined, often entailing a number of assumptions about etiology.8 For the purpose of the present study, somatization has been defined in the broadest sense, namely, as the presentation of medically unexplained symptoms or, in other words, physical symptoms that cannot be (adequately) explained by organic findings.33 and 34 This study is part of a larger longitudinal study examining the respective contribution of the personality traits neuroticism and alexithymia, negative affect (psychological distress) and positive affect to increases (decreases) in the number of symptoms reported and to the persistence of symptoms over a 6-month time period. The objective of the present study is to test the assumption that, within a population of patients presenting to their primary care physician with medically unexplained symptoms, the personality traits neuroticism and alexithymia remain stable over time, whereas the affective state dimensions change significantly over time.
