Specific phobia of vomiting (SPOV, also known as emetophobia) is still unknown among 29.7% of eating disorder specialists [1
]. The rate of clinical practitioners who have never heard about SPOV may even be higher and research on the topic is extremely scarce in the scientific community. Consequently, it is not unreasonable to assume that patients with SPOV may often be misdiagnosed.
SPOV typically begins in childhood and leads to considerable impairment [2
]. Patients with SPOV avoid situations which may increase their risk of vomiting themselves (e.g., eating certain food, traveling, going to an amusement park, meeting ill people, pregnancy...), seeing someone vomiting (e.g., events where guests drink alcohol, meeting pregnant women, places where children play...) [2
] or vomiting in the presence of others [4
]. Hence, patients avoid situations with a high perceived threat value of vomiting. Vomiting cues lead to imagination of worst-case scenarios and activation of autobiographical memories, which in turn maintain the fear of vomiting [5
]. By consistently avoiding these situations, such biased and catastrophical scenarios about the threat-value of a situation remain uncorrected.
Moreover, avoidance behavior related to these worst-case scenarios may complicate matters for clinicians in the diagnostic process. A common avoidance behavior in SPOV is food restriction [7
], which could potentially lead to misdiagnoses of anorexia [8
] or phagophobia [9
]. Avoidance behavior of social meeting places (i.e.
, restaurants) due to a fear of vomiting in the vicinity of others, may lead to misdiagnoses of social phobia or agoraphobia [10
It is therefore important to find distinguishing characteristics of SPOV. An important and potentially distinctive feature of SPOV which could support accurate diagnoses is the occurrence of nausea. Nausea is defined as a discomforting and unpleasant sensation related to the gastrointestinal system. Prior research shows that nausea is indeed regarded as a troublesome symptom in patients which gravely impacts the patients quality of life (e.g., [11
]). Interestingly, approximately 10% of the cases which report to (Australian) physicians with complaints of nausea remain undiagnosed [12
]. Klonoff et al.
] already provided a description of fear of nausea which was closely related to current definitions of fear of vomiting, in line with the idea that nausea may be particularly relevant to the etiological processes in SPOV. Further, nausea correlates with anxiety [14
] and gastrointestinal complaints appear to be significantly associated with a number of anxiety disorders [15
]. In addition, while nausea or gastrointestinal symptoms are acknowledged as secondary symptoms in social phobia [15
] they could play a more crucial and central role in the development of SPOV. Recent work showed that patients with SPOV demonstrate higher levels of disgust propensity (i.e.
, tendency to experience disgust) and disgust sensitivity (i.e.
, tendency to evaluate the experience of disgust as a negative experience) compared to a control group without SPOV-complaints [17
]. Hence, SPOV could be interpreted as fear of highly aversive, physical cues (i.e.
, nausea) which are identified as a potential precursor of the catastrophic scenario of vomiting.
If nausea is indeed relevant for the development of SPOV, nausea could be the predominant symptom perceived by patients with SPOV. According to Boschen [18
] nausea in SPOV is due to an increased vulnerability to gastrointestinal anxiety symptoms. Davidson et al.
] reports a higher scoring on the Internal Locus of Control Scale with regard to both general and health-related issues in patients with SPOV. Thus, patients regard nausea and vomiting as being within their influence and try to control these circumstances by rigorous avoidance behavior. Ironically, the more they pay attention to gastrointestinal symptoms, the more likely it becomes that they may perceive nausea. Fearing nausea as a precursor of vomiting leads to selective attention and hypervigilance to gastrointestinal symptoms. Boschen [18
] described these cognitive aspects of SPOV. Minimal signs of digestion activity can be catastrophically misinterpreted as indicator for an upcoming nausea, leading to increased anxiety which, in turn, leads to nausea per se [20
]. These self-fulfilling fears are not only easily triggered, but also occur in a vicious circle. The more nausea the patient experiences, the more fear raises. Indeed, fear leads to increased hypervigilance and, thus, to stronger feelings of nausea.
Because nausea is possibly a very important symptom in SPOV, the major aim of this study was to further describe and delineate the role of nausea in fear of vomiting and to investigate whether nausea is indeed a core symptom. Hence, we addressed the following research questions:
First, we examined whether fear of vomiting was associated with increased levels (and/or a history) of nausea. Therefore, we asked whether participants experienced nausea, asked about the frequency and duration of nausea attacks and asked specific questions to establish how disturbing nausea actually was to the participants. Second, we examined the role of nausea in the course of development of fear of vomiting. Thus, we investigated the onset of nausea in relation to the onset of fear of vomiting. Additionally, we explored whether nausea was associated with core features of the fear, such as locus of fear, intensity of fear, and duration of fear. Third, we were interested in how participants handled nausea, whether they consulted a physician and whether they had any theories about the causes of nausea. Finally, the fourth aim of the study was to investigate whether nausea may complicate the diagnostic process. Therefore, we examined whether higher nausea levels were associated with body weight and eating behavior. This could potentially lead to misdiagnoses of anorexia, for example. At the very least, it would indicate the great difficulty in establishing proper diagnoses when not taking SPOV into account when nausea is a predominant feature in the clinical image of a patient.
2. Experimental Section
The Ethics Commission Salzburg/Ethikkommission Land Salzburg was consulted. This Commission rated an internet survey as not being legally bound to be subject to approval. Therefore, the study was just submitted for the attention of the Internal Review Board of the University Clinic of Neurology, Salzburg. The study was designed and carried out according to the ethical requirements as stated in the Declaration of Helsinki.
2.2. Study Population
Participants were recruited at the German internet forum www.emetophobie.de [21
]. Therefore, the participants were german speaking and most likely resided in German-speaking countries (e.g., Germany, Austria, Switzerland, Luxembourg, and Liechtenstein). Compiled questionnaires were received from 145 subjects between October 2007 and February 2008. There were late responses from 9 subjects between March 2008 and June 2009. In this sample (N = 154), there were 6 men.
We selected subjects meeting the DSM-IV-criteria [22
] for specific phobia according to their answers in the questionnaire. Participants had to give adequate answers (in parenthesis) to the following questions:
“Are you afraid of vomiting? (yes)” AND
at least one of the following:
“Does the fear of vomiting prevent you from leading a normal life? (yes)”
“Do you think you eat normally, as other people do? (no)” AND “Why do you eat differently? (afraid of vomiting)”
“Do you abstain from certain dishes because of the emetophobia? (yes)”
AND “Are there other things that you avoid because of the fear of vomiting, apart from certain dishes? (yes).”
According to these criteria, 23 participants had to be excluded, resulting in a sample of N = 131. Criterium 2 was distributed as follows: 96.9% participants were impaired in their everyday life because of fear of vomiting, 80.4% (n.a. 26%) indicated an impaired eating behavior, and 61.3% (n.a. 1.5 %) refused eating certain dishes because of the fear of vomiting.
2.3. SPOV Survey
The questions for the survey were designed by the authors. The resulting questionnaire included 36 items and additional questions about the participants’ demographics. It was designed to measure emetophobic complaints. The questionnaire included the items used by Lipsitz et al.
]. Additionally, several new items were constructed to examine the circumstances and consequences of nausea as well as the participants’ eating behavior. A 4-point-Likert-scale (“strongly agree”, “partly agree”, “partly disagree”, “strongly disagree”) was used whenever it was applicable.
In the present manuscript, not all results on all items are reported because some of them ended up being uniformative, or would not fit thematically to the nausea-specific topic (e.g., we asked participants if they received psychotherapy). The items from which information was extracted for this manuscript were translated from German to English and are attached in the supporting information
Participants were recruited to voluntarily complete the questionnaire by advertising in the online forum and support group www.emetophobie.de [21
]. The advertisement included a link to download the questionnaire and an e-mail address indicating where to send the completed questionnaire. The survey took about 20–30 min to complete. There was no remuneration for participants. The questionnaires were processed anonymously.
Data was entered in IBM-SPSS Version 18. We report valid percent and, if applicable (> 0), the percent of participants without an answer (“no answer”, n.a.) in the respective question. That is, the valid percentage was calculated on the sample excluding the proportion of participants without an answer.
We calculated the median of the following questions: (a) “I suffer from nausea”, “You feel so nauseous... (b)...that you think you won’t stand it any longer”; (c) “...that you nearly have to vomit?”; (d) “Does this nausea interfere with your routine duties?”. This median was our composite nausea score (n.a. in 11 participants because of missing answers). Next, we grouped the sample into participants with a composite nausea score “strongly disagree” or “partly disagree” (low nausea group, N = 80) and participants with a composite nausea score “strongly agree” or “partly agree” (high nausea group, N = 40).
To examine the relationship between nausea and core features of the fear we calculated two Mann-Whitney-U tests with the nausea group (low/high) as the independent variable and (a) fear-rating and (b) duration of fear as the dependent variables. Additionally, we calculated a chi-square cross tabulation for nausea group and locus of fear (self, others, both), as well as a Kruskal-Wallis test with locus of fear as the independent variable and fear-rating as the dependent variable.
We were interested in associations between nausea levels and body weight and/or eating behavior. Therefore, we tested the relationship between food avoidance and nausea with a chi-square cross tabulation for nausea group and food avoidance (yes/no). To examine the relationship between nausea and body weight, a chi-square test was calculated with the variables nausea-group and BMI group (underweight vs. pooled normal weight + overweight; normal weight = 19–25; the overweight group consisted of 8 participants, and was therefore pooled with the normal weight group). In addition, we examined if BMI was influenced by eating-related avoidance behavior by calculating a One-way ANOVA with eating related avoidance behavior (yes, no) as the independent variable and BMI as the dependent variable.
In this study we examined the role of nausea in participants with fear of vomiting. Nausea appears to be a common and frequent symptom in people with fear of vomiting. This symptom is associated with increased levels of nausea, it impairs daily routines, is associated with duration of fear, and is thus perceived as very threatening symptom of the fear of vomit. Nausea is not necessarily a precursor or a consequence of fear of vomiting, so further investigations are needed to model the interactions of fear and nausea during the development of SPOV. Since nausea causes people to consider a physician, it is necessary to increase the awareness for SPOV among medical practitioners, especially internal specialists, to avoid misdiagnoses. This is especially important with respect to evidenced relationships between eating behavior/weight and nausea.
In summary, the role of nausea in development, maintenance, and clinical manifestation of SPOV may have been underestimated until now. As a consequence, nausea should be paid more attention when designing a treatment. Future research should examine the fear and avoidance of nausea in SPOV, because these factors could be crucial in maintaining the anxiety disorder.