5 Intra-Oral Injection Phobia


Intra-Oral Injection Phobia

Margrethe Vika and Maren Lillehaug Agdal

Blood-Injury-Injection Phobia

Blood-injury-injection (BII) phobia is one of five different types of simple phobias classified in the DSM-IV (American Psychiatric Association 1994). BII phobia may be considered as one of the most serious phobias since the avoidance of stimuli associated with it may lead to ­avoidance/denial of necessary dental and medical treatment (Marks 1988; Vika et al. 2008). BII phobia is characterized by extreme and excessive anxiety in connection with one or more of the following situations: seeing blood or injury to oneself or others; watching another person get an injection; receiving injections (intra-oral and/or extra-oral); and/or exposure to other invasive medical/surgical procedures.

The fear reaction associated with BII phobia and the subtype, intra-oral injection phobia, may be triggered by several stimuli related to the syringe and/or the needle: seeing the syringe/needle; experiencing the needle penetrate the gums; the feeling of being anaesthetized; the sensation of swelling gums; fear of not being adequately anaesthetized; fear of tissue damage; and fear of allergic reactions related to the injection fluid (Öst et al. Unpublished; Raadal et al. 2010). Furthermore, for specific phobias in general, most of the phobics report catastrophic thoughts regarding the consequences of facing the feared stimuli. This is also true for intra-oral injection phobics (see Catastrophic Beliefs in BII Phobics below).

Prevalence, Subtypes and Gender Differences

The lifetime prevalence of BII phobia is reported to be about 3.1–4.5 per cent of the adult population (Agras, Sylvester and Oliveau 1969; Bienvenu and Eaton 1998; Curtis et al. 1998; Depla et al. 2008; Stinson et al. 2007). These subgroups are fear of physical injuries 0.8 per ­cent; blood 0.8–1.0 per cent; and injections 1.1–1.6 per cent (Fredrikson et al. 1996). Injection phobia can be divided into two separate subgroups, namely phobia of extra-oral injections (on the skin) and phobia of intra-oral injections (in the mouth). The exact prevalence and degree of overlap is not well established, since most of the studies do not differentiate ­between the two subgroups. Differences in both diagnostic criteria and measurement methods may also cause inconsistent prevalence figures in the literature. In a sample of 1385 adolescents, 18 years of age, Vika et al. (2006) found that of the 17 per cent that reported fear of ­injections, 8.1 per cent were highly fearful of both intra- and extra-oral injections, whereas 7.7 per cent and 8.4 per cent reported high fear of extra-oral injections and intra-oral ­injections, respectively.

In general women report simple phobias more often (2:1) than men, whereas gender ratio in BII phobia varies in different studies (Fredrikson et al. 1996; Oosterink, de Jongh and Hoogstraten 2009). Two studies by Bienvenue and Eaton (1998) and Beesdo, Knappe and Pine (2009) found higher prevalence of BII phobia in females (female: 4.4–6.4 per cent; male: 1.8–3.9 per cent) whereas Fredrikson et al. (1996) found no gender differences. However, regarding the subtype injection phobia Fredrikson et al. found that 1.9 per cent of the women and 1.2 per cent of the men reported this phobia.

Catastrophic Beliefs in BII Phobics

In general, a common model for explaining the aetiology of anxiety disorders claims that it is the individual’s judgements and beliefs about possible threats in relation to the feared situations or stimuli that maintain the anxiety. Most research in this area has been in relation to panic disorder. Patients with panic disorder may interpret the normal fear reactions (e.g. increasing heart rate and respiratory frequency) as signs of serious somatic illness (Latas, Obradovic and Pantic 2009). In the literature these assumptions and interpretations are often referred to as catastrophic thoughts. The catastrophic thoughts may appear differently across the various anxiety disorders. Usually, patients carry out safety behaviours in order to prevent catastrophic beliefs from occurring (Salkovskis, Clark and Gelder 1996).

Öst et al. (unpublished data) investigated the prevalence and quality of catastrophic beliefs in a sample of patients with intra-oral injection phobia. Based on information from a diagnostic interview, the catastrophic beliefs were classified into the following categories: ‘physical’, ‘mental’ and ‘social’. Sixty-seven percent of the patients were classified with a physical catastrophic thought. The most frequent thoughts were fear of bodily harm/injury and fear of dying, with frequencies of 24 per cent and 18 per cent, respectively. The most frequent mental fears were reported to be fear of going insane and losing control (with and without ‘acting out’). Only 5 per cent of the phobics reported fears in relation to the social category.


For most specific phobias the onset of BII phobia is during childhood. The median age of onset is 5.5 years and the mean age of onset is about 9.4 years (Bienvenu and Eaton 1998; Lipsitz et al. 2002). In a study by Öst (1987) the age for the onset of blood and dental phobia was 8.8 and 11.7 years, respectively.

BII phobia is a specific phobia with the highest reported family prevalence. Up to 60 per cent reported that they had parents or siblings with fear or phobia of BII stimuli (Öst 1992). The reason for the high figure may also be closely related to the emotional ­sensitivity in BII phobia.

There are associative and non-associative means of becoming BII phobic (Coelho et al. 2010). Perception of a painful dental injection is an example of a common classical ­conditioning to dental injections. The sufferers may have catastrophic thoughts and/or other dysfunctional thoughts in relation to the feared situation. An elevated certainty that the events they feared ‘really’ would occur, shared with low expectancies for dealing with the phobic situations or events if they occurred, may decrease the sense of control (Logan et al. 1991). Previous studies have shown that experiences of pain increase the risk of the patient developing dental anxiety. Additionally, pain combined with lack of control multiply to a large degree the risk of the patient developing dental anxiety (Law, Logan and Baron 1994; Logan et al. 1991; Milgrom, Vignehsa and Weinstein 1992). It seems reasonable to believe that experiences of pain and lack of control will have a similar relationship in connection with fear of intra-oral injections.

Vicarious conditioning, modelling, visual observation of fear and negative information/instruction transmission may cause some to become phobic of BII stimuli (Öst 1992), without themselves having a direct negative experience. Usually children observe how their parents or siblings relate to their surroundings. Children’s observations of parents or siblings reacting with high anxiety to BII stimuli are also a risk factor for developing high BII anxiety. It is important that medical staff are aware of these conditional factors when providing medical care. In addition, one must realize that these learning processes may influence the children in a positive manner when the ‘model’ is performing a positive behaviour in the dental situation.

Most of us remember vicious rumours about medical injections. When the majority felt a bit frightened, the rumours kept others from having the injections, or they had them despite significant clinical distress. But why is it that some individuals become phobic and others remain without anxiety after a negative experience?

Furthermore, why will some become anxious after an episode of vasovagal syncope, while others seem unaffected? This may be explained by non-associative means which include psychological preparedness (Seligman 1971) or vulnerability (Beck, Emery and Greenberg 1985, Marks 1988) and a high level of general fearfulness (Öst 1987). Vulnerable patients are more cautious of the situation being dangerous, uncontrollable, unpredictable and disgusting (Armfield 2010). Some individuals are assumed to have lower thresholds for activations of the ‘fight-or-flight’ response and they may also have excessive and prolonged responses in relation to ‘false alarms’ (Barlow 1988). This may be partly explained due to innate vulnerability. Also, strong feelings of disgust and repulsion may be the cause of high anxiety in vulnerable persons. The fear, anxiety and avoidance associated with the specific object or situation are, however, not restricted to the symptoms of disorder (LeBeau et al. 2010). It seems likely that separating emotions from cognitions is highly problematic because of the interconnectedness and parallel processing in the brain (Gray, Braver and Raichle 2002).

Mowrer’s (1960) two-factor theory of avoidance is highly influential in the maintenance of anxiety. Fears develop initially via classical conditioning and then are maintained via operant conditioning with negative reinforcement (avoidance). The avoiding nature of the phobia increases the anxiety level and may also keep the patient from seeking help to overcome the anxiety.

Fainting response

Unique for BII phobia is the relatively large tendency to faint (Bienvenu and Eaton 1998; Hallam, Connolly and Marks 1976; Kleinknecht and Lenz 1989; Öst 1992) as compared to other specific phobias. Estimates of the frequency of fainting in the presence of blood, injury and injections are inconsistent and vary between 5–80 per cent or more (American Psychiatric Association 1994; Kleinknecht, Thorndike and Walls 1996; Page 1994). Consistent with the frequency of fainting in the adult population, Vika et al. (2006) found that 7.4 per cent of Norwegian adolescents had fainted during medical injections. In the dental situation the frequency of fainting was lower, while 15.9 per cent reported that they had nearly fainted during dental injections, only 1.7 per cent had actually fainted.

Engel and Romano (1947) described the fainting process as a biphasic response to the BII stimuli (see also Graham, Kabler and Lunsford 1961). Typically, when patients are exposed to BII stimuli they will first experience increased heart rate and blood pressure, which are typical physiological reactions in the anxiety response. Shortly after the sympathetic flow, there is a cardiovascular deceleration, meaning a marked drop in blood pressure and/or in heart rate (Connolly and Wieselberg 1976; Öst, Sterner and Lindahl 1984; Thyer and Curtis 1985). This deceleration is due to activation of the parasympathetic nervous system (Levenson 1992). The patient becomes pale and sweats and may experience a vasovagal syncope.

It has been discussed whether some of the individuals who faint in relation to BII stimuli may have a common genetic disposition or an underlying circulatory dysregulation that ­predisposes them to vasovagal syncope. This atypical fainting response pattern may be assumed as an appropriate response in situations where injury may cause major blood loss. One may claim that individuals who faint and thereby have decreased blood pressure may suffer from less blood loss. Furthermore, fainting may be consistent with the ‘playing dead’ mechanism as observed in many animal species in relation to specific fears (Accurso et al. 2001). The animal may then be less likely to be attacked by predators.

Disgust and disgust sensitivity in BII phobics

BII phobia differs significantly from most other specific phobias in that BII phobics may report disgust in relation to the phobic stimuli. Clinical and experimental evidence suggest that exposure to BII stimuli evokes reactions of aversion and nausea (Gross and Levenson 1993; Rachman 1990). Disgust has been identified as a basic emotion (Ekman 1992) and is characterized by well-defined and reliable physiological (e.g. nausea), expressive (e.g. facial), behavioural (rejection) and interpretive (e.g. contamination) response components (Rozin, Haidt and McCauley 1993). In contrast with the acute sympathetic nervous system reaction (e.g. cardiovascular acceleration) associated with the fear response to phobic stimuli (Ekman, Levenson and Friesen 1983; Gelder and Mathews 1968), the physiological mechanism of ­disgust reflects parasympathetic activity (nausea, dizziness and fainting) (Ekman et al. 1983). The disgust sensitivity is found to be positively associated with fainting in BII phobics and especially for the subtype blood phobia (Hepburn and Page 1999).

In contact with blood, injection or injury stimuli the disgust-mediated aversion may serve both preventative (i.e. escape and avoidance with the goal of evading physical contact and ­contamination) (Rachman 1990; Sawchuk et al. 2002) and reactive (i.e. purging and vomiting following contact or ingestion) functions. One of the theoretical models discussing the ­relationship between cognitions and emotions claims that emotional responses appear before cognitions and that acquisition of BII phobia is known to be followed by sensitivity to emotions and physiological reactions. Unlike other specific phobias, the emotional response for some BII phobic patients is the strong feeling of disgust and repulsion and not threat-induced fear (Page 1994; Sawchuk et al. 2002; Tolin et al. 1997). Research is, however, unambiguous as to whether patients who are prone to feel disgust in relation to BII stimuli are more sensitive to becoming BII phobic (De Jong and Peters 2007; Kleinknecht, Kleinknecht and Thorndike 1997; Matchett and Davey 1991; Merckelbach et al. 1999). Page (2003) suggested that the sense of disgust is highly related with fainting. The emotional response to the sense of disgust may accelerate both the anxiety and the fainting response due to previous conditioning experiences.

Regardless of the increased interest in the relationship between fainting in BII phobia and disgust, the literature remains equivocal, where some argue that the relationship between them is entirely explained by the covariance between fear and disgust, rather than disgust being a direct predictor for fainting (Kleinknecht et al. 1997; Olatunji et al. 2006; Schienle et al. 2003). Another problem with investigating the role of disgust in relation to BII phobia may be that the term disgust is not consistently defined in the different studies. In some studies the term disgust is related to nausea and dizziness (and fainting), which is a normal anxiety reaction. In other studies disgust appears as a concept describing the perception of being contaminated and infected.

Overlap between BII Phobia and High Dental Anxiety

According to DSM-IV (American Psychiatric Association 1994), dental phobia is classified as a subtype of BII phobia. Most studies report a considerable but varying, estimate of overlap between BII anxiety and dental anxiety. These variations may be explained due to differences in diagnostic criteria, levels of anxiety, different subtypes and so on. Among patients with high dental anxiety 16–56.7 per cent (De Jongh et al. 1998; Locker, Shapiro and Liddell 1997) are classified as BII phobic. On the other hand 8.2–56.7 per cent of patients with BII phobia have high dental anxiety (De Jongh et al. 1998; Öst 1992). Dental phobic patients often consider dental injections as extremely anxiety provoking. In a study from the Netherlands 39 per cent of patients with high dental anxiety reported fear of having a dental injection (De Jongh et al. 1998). A community study from Norway found that fear of dental injections is prevalent among adolescents: 5–7 per cent reported that fear of injections may lead to avoidance of necessary dental treatment (Vika et al. 2006). In particular, girls were more prone than boys at avoiding dental treatment. This is in agreement with Liddell and Locker (1997) who found that women are more anxious about the risk of painful experiences; they are more prone to avoid pain and they have lower acceptance of pain.

The close relationship between BII phobia and dental phobia is only partly described by the stimuli that the patients are anxious about. During dental treatment BII stimuli are presented as dental injections and as procedures involving blood, like extractions, periodontal treatment and surgery. Patients who have intra-oral injection phobia may avoid dental injections because of their anxiety. Consequently, they are more likely to experience pain in the dental situation. Isolated fear of pain is a predictor of dental fear (McNeil and Berryman 1989; Skaret et al. 1998) and experience of painful dental care is the most potent stimulus in classical ­conditioning for dental anxiety. Studies have found that painful dental treatment, where the patient does not perceive control of the situation, multiply the likelihood of developing dental anxiety (Milgrom et al. 1992; Skaret et al. 1999).

However, BII phobia is not synonymous with the patient developing high dental anxiety. There are differences in patients’ perception and meaning of the painful experience (Liddell and Locker 1997). If patients recognize the pain as harmful to teeth and soft tissue, they tend to respond with more anxiety. This may reflect the patients’ feeling of control. Patients’ need and desire for control is of high importance in relation to dental treatment. Patients who desire control, but do not feel control in the dental situation, are the most dentally anxious (Law et al. 1994; Locker et al. 1997). This may partly explain why some patients with BII phobia develop dental phobia, whereas others do not become dentally anxious. Women tend to have a stronger desire for control and they also tend to be more dissatisfied with the level of control they feel in the dental situation, as compared to men (Liddell and Locker 1997).

Whereas BII phobia and specifically avoidance of intra-oral injections may cause dental anxiety due to painful dental experiences, studies have shown that intra-oral injections per se is a source for dental anxiety both in adults and children (Cuthbert and Melamed 1982; Milgrom et al. 1997). The pain experienced during dental injections may be the painful dental experience leading to dental anxiety. It is therefore of utmost importance that dental staff are aware of the potential of generalizing painful dental experiences.

It has been discussed whether dental phobia should be diagnosed as a subtype of BII phobia. De Jongh et al. (1998) argue that dental phobia should be considered a specific phobia, independent of the BII subtype despite the similarities between the phobias whereas LeBeau et al. (2010) justify that dental phobia is diagnosed as a BII phobia in the review for DSM-V.

Dental Health in Intra-Oral Injection Phobics

Avoidance of and delay in seeking medical care among patients with BII phobia may have serious health consequences (Kleinknecht and Lenz 1989; Öst 1992). BII phobia may be associated with avoidance of dental treatment that involves blood, injury and particularly a fear of intra-oral injections which may keep patients from having dental injections. Consequently, this fear prevents them from being able to undergo invasive procedures like extractions, drilling, filling and so on. Other procedures may be endured resulting in painful dental experiences.

Patients with dental phobia have a poorer oral health compared with the regular population. They have more decayed teeth and more missing teeth (Agdal et al. 2008). Patients with BII phobia have oral conditions similar to i/>

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Jan 20, 2015 | Posted by in General Dentistry | Comments Off on 5 Intra-Oral Injection Phobia
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