Auricular Acupressure Improves Habit Reversal Treatment for Nail Biting

Abstract

Objective:

Nail biting leads to a variety of health issues. Habit reversal treatment is a major approach to cease nail biting, but is often ineffective since patients continue to suffer from anxiety, a major trigger. This study investigated whether the potential anxiety relief provided by auricular acupressure could improve the efficacy of habit reversal treatment, as evidenced by improved stomatological and other outcomes.

Methods:

In a pragmatic, randomized, crossover, pilot clinical trial, 83 nail biters (8–12 years old) received habit reversal treatment in combination with either auricular acupressure intended to reduce anxiety (Method A) or placebo auricular acupressure (Method B). The alternative protocol was employed after a two-month washout period. The primary outcome measured was the 41-item child self-reported version of the Screen for Child Anxiety Related Emotional Disorders, while the secondary outcomes were the nail growth status (NS), which represented the fingernail growth of each finger during habit reversal treatment, simplified plaque index (SPI), and the simplified gingival index (SGI) as measures of oral health. A paired sample t-test was used to assess the differences between Methods A and B, and the differences in the anxiety scores, NS, SGI, and SPI between the baseline and each time point.

Results:

Forty-one children successfully completed both arms of the treatments and attended all appointments. There were significant differences in the efficacy of habit reversal treatment, the anxiety score, the nail status, and the SGI in favor of Method A (p < 0.001).

Conclusion:

Auricular acupressure appears to improve the efficacy of habit reversal treatment, likely by reducing anxiety.

Introduction

Nail biting is a common, but difficult to resolve behavior. Children who bite their nails can suffer from various acute and chronic injuries, such as loss of the nail bed, unilateral chewing, dental abrasions, gingival inflammation and injury, temporomandibular dysfunction, and even severe malocclusion.¹ Secondary oral or respiratory infections are also possible complications because of the high levels of bacteria present under fingernails.²

Various treatments are used for nail biting, including punishment, encouragement, psychotherapy, habit reversal treatment or training (HRT), and pharmacological therapy. HRT is efficacious for a variety of maladaptive behaviors.³ However, it has some limitations, including the fact that not all patients respond. HRT has sometimes been viewed as an inadequate intervention because it fails to address an individual's emotional status and anxiety level.³ Therefore, it has been suggested that HRT should be reinforced by other treatment(s) that target the underlying psychological causes and effects of nail biting.

Boredom, frustration, and anxiety are commonly cited reasons why people bite their nails.^4,5 Although nail biting is known to be a pernicious habit,⁶ it serves an adaptive function to obtain pleasure and subdue anxiety symptoms, so patients may persist in the behavior despite knowledge of its potential for harm. We wondered whether relieving anxiety during conventional HRT would improve the outcome of treatment.

Acupuncture and acupressure have been used as traditional medicine to address a variety of disorders. Several studies have demonstrated that auricular acupuncture or acupressure can reduce anxiety.^7

–14 We therefore assessed the outcomes of using auricular acupressure to reduce anxiety in combination with HRT. In this study, auricular acupressure intended to reduce anxiety^7

–12 was applied in combination with HRT. We compared the outcome of this treatment to that of patients treated with the same HRT procedure in combination with “placebo” acupressure without any expected effects on anxiety, and then switched the treatments after a brief washout period. We determined the nail growth status (NS), the simplified plaque index (SPI), the simplified gingival index (SGI), and the Screen for Child Anxiety Related Emotional Disorders (SCARED) score to evaluate the efficacy of the treatments.

Methods

Ethics

The ethics committee of the First Affiliated Hospital of Xinjiang Medical University approved this randomized, pragmatic, controlled, blinded, and crossover pilot trial (No. 20160226-03), which complied with the 2008 Declaration of Helsinki. Only students whose parents provided written informed consent were included in the study.

Sample size

The sample size calculation was performed for a comparison between Method A (HRT with acupressure intended to have antianxiety effects) and Method B (HRT with acupressure of points considered to be unrelated to anxiety) with a hypothesis of superiority and a two-sided (alpha = 0.05) paired-samples t-test to provide 80% power. Based on a pilot trial, the mean difference in the NS for Method A between the pretreatment and post-treatment evaluations was 17.33%, while that for Method B was 12.70%. The standard deviation of the mean difference in the NS between the pretreatment and post-treatment evaluations in the total number of participants (Method A+ Method B) was 8.16. Accordingly, we estimated that 11 participants were needed for each group to complete the study.¹⁴ However, given the high trial dropout rates for a two-sequence, two-period crossover design, we expected that recruitment of more than 40 enrollees for each group would yield at least the above-mentioned number of completers.

Recruitment

The participants (8–12 years old) were enrolled from a primary school in Urumqi, China. Each eligible participant¹⁵ had to have been biting his or her nails for at least 8 weeks, had to bite their nails at least five times per day, and had to experience social impairment (e.g., hiding hands) because of their nail biting or have physical symptoms (e.g., nail bleeding). There were at least five fingernails affected in every individual, and the NS of all participants was less than 90% (Fig. 1). The participant's maxillary teeth (55, 21, and 26) and mandibular teeth (75, 42, and 46) were present without decay or inflammation.

FIG. 1.

The measured ratio of the fingernail to the fingertip represented the nail growth status.

Children were excluded if they had a history of local or systemic infection, analgesic medication, previous experience with acupuncture or acupressure, lesions on the external ear, acute dental inflammation, coagulation disorders, or the diagnosis of a psychiatric disorder. Those with mild temporary nail biting or who were taking medications to help stop their habit (including antianxiety medications) were also excluded. Children and parents who refused to participate or did not provide written informed consent were excluded.

Study sequence

All children and their parents provided verbal and written consent to participate in the study and the proposed treatments. The NS, SCARED anxiety score, SGI, and SPI were recorded at baseline before treatment. The HRT consisted of two parallel procedures and lasted from May to October 2016. For group I, the participants experienced Method A from May to June, and then, after a 2-month washout period (July and August), experienced Method B from September to October. For group II, the participants experienced Method B from May to June, and then, after a 2-month washout period (July and August), experienced Method A from September to October.

Method A comprised anxiety-reducing auricular acupressure plus HRT based on the Woods protocol.¹⁶ Auricular acupressure was performed using five points with demonstrated anxiety-reducing effects: the sympathetic point (MA-AH7), Sanjiao point (MA-IC4), heart point (MA-IC), Shenmen point (MA-TF1), and adrenal gland point (MA-TG).^7

–12 Method B comprised “placebo” auricular acupressure plus HRT based on the Woods protocol. The “placebo” auricular acupressure was performed at five points not considered to have anxiety-reducing effects: the heel point (MA-AH1), ankle point (MA-AH2), knee point (MA-AH3), hip point (MA-AH4), and buttock point (MA-AH5).

Randomization

The sequence of the procedures was randomized using random numbers generated from random number tables. The random numbers were sealed inside consecutive opaque envelopes numbered 1–83. Children with odd numbers were allocated to group I and those with even numbers were allocated to group II. The randomization was performed by an individual who was not directly involved in the clinical aspects of the research. Each child's envelope was opened independently by the acupuncturist (performing acupressure) before treatment.

Blinding

The participants were blinded to the type of auricular acupressure used. The psychologists, investigators, and data recorders were blinded to the sequence into which the participants were randomized to prevent them from inadvertently influencing the outcome.

Auricular acupressure

The magnetic seeds (Suzhou Gusu Acupuncture & Moxibustion Appliance Co., Ltd.; Fig. 2), which had an adhesive backing, were applied by an acupuncturist/acupressurist with more than 10 years of experience by sticking them onto one of the nail biters' ears. After 7 days, these were removed, and five new seeds were stuck on the same points of the other ear. The participants pressed the acupressure points with the seeds thrice a day for 20 seconds per time under parental supervision. The children's self-compression led to feelings of local acid/a sour taste, or mild swelling, pain, and/or a burning sensation. None of the patients stopped the treatment due to these sensations.

FIG. 2.

The magnetic seeds used for auricular acupuncture.

HRT procedure

Habit reversal treatment was conducted based on the criteria formulated by Woods.¹⁷ The HRT consisted of three programs: awareness training, competing response training, and social support training. It took about 30 minutes to educate the students and parents about the program, with education conducted in a classroom. During awareness training, nail biters were trained to become aware of their nail-biting behavior and its warning signs. For competing response training, children learned actions to reduce nail biting immediately after the appearance of nail biting or one of its warning signs. For example, they were asked to clench their fists for 2 min and put their hands by their sides, or clench and grasp an object, such as holding an eraser or a pencil with their hands. Finally, during social support training, a parent was identified to support the child to improve adherence during the HRT, and to remind them about their competing response, as well as to reward their compliance. To avoid unnecessary confounding factors, only one parent was designated the support person for each child since parents may approach the treatment and support patients suffering from anxiety-related habits differently.

Assessment of the nail status

The lengths of the fingertips (in millimeters) from the base of the nail to the highest point on the tip of the fingertip, and the lengths of the individual fingernails (in millimeters) from the base of the nail to the highest point on the tip of the nail, were measured before the nails were cut and during the follow-up period (every week) throughout the entire study by the same trained research assistants. The ratio of the fingernail to the fingertip represented the nail growth status (NS) (Fig. 2), and the mean ratio was calculated across all 10 fingernails during the follow-up period.

Oral examination

Patients who bite their nails often suffer from dental abrasions and gingival inflammation and injury.¹ Therefore, we assessed several oral parameters to assess the impact of the nail-biting habit and the interventions on the patients' oral health. The gingival index¹⁸ was calculated for each patient as follows: score 0—normal gingiva; 1—mild inflammation, slight color change, slight edema, and no bleeding on probing; 2—moderate inflammation, redness, edema, and bleeding on probing; 3—severe inflammation, marked redness and edema, ulceration, and tendency to spontaneously bleed. The plaque index (PI) was also recorded for each subject according to the Silness and Loe plaque index method.^19,20 Plaque accumulation was graded as 0 = no plaque, 1 = mild plaque only disclosed with a dental probe, 2 = moderate plaque around the gingival margin seen with the naked eye, and 3 = abundant soft debris around the gingival margin.

We used the simplified GI and simplified PI,²¹ which incorporated the labial or buccal surfaces of six teeth. The teeth that were evaluated at each visit included three from the maxilla (55, 21, and 26) and three from the mandible (75, 42, and 46). The SGI and SPI for each of the six teeth were graded and recorded, and then a mean score was calculated. To rule out measurement errors, all investigators received consistency training.

Anxiety scores

Eighty-three children participated in the study and filled out the 41-item child self-reported version of the SCARED²² in the Medical Psychology Center of the First Affiliated Hospital of Xin Jiang Medical University at baseline and at every visit. The children filled out their own questionnaires under parental supervision. The SCARED includes five factors: somatic/panic (13 items; e.g., “When I feel frightened, it is hard to breathe”), generalized anxiety (9 items; e.g., “I worry about other people liking me”), separation anxiety (8 items; e.g., “I get scared if I sleep away from home”), social phobia (7 items; e.g., “I don't like to be with people I don't know well”), and school phobia (4 items; e.g., “I get headaches when I am at school”). The participants rated the items for each factor on a three-point scale (0 = not true or hardly ever true, 1 = sometimes true, and 2 = true or often true). The SCARED total score, derived by adding the responses for the 41 items, therefore ranges from 0 to 82, with higher scores indicating greater anxiety. A score ≥23 effectively discriminates between anxious and nonanxious subjects.²³

Statistical analysis

The sex, NS, anxiety scores, and SPI and SGI values were compared between the two groups using independent sample t-tests, and the chi-squared test was used to examine the differences in age. A paired sample t-test was used to assess the differences between Methods A and B, and the differences in the NS, anxiety scores, SGI, and SPI between the baseline and each time point. The data analyses were performed using SPSS for Windows (Version 16.0, IBM Corp., New York). All data are presented as the mean (±standard deviation). Two-sided p-values <0.05 were regarded as significant.

Results

As noted above, we previously performed a pilot study and estimated that 11 participants were needed for each group to complete the study.¹⁵ However, due to the two-sequence, two-period crossover design, we expected that there would be relatively high dropout rates. Therefore, we recruited a total of eighty-three students for the study, 41 of whom finally attended all visits and completed both arms of treatment. The sex, age, and clinical characteristics (NS, anxiety, SGI, and SPI) for Groups I and II showed no significant differences at baseline (Table 1).

Table 1.

The Baseline Characteristics of the Subjects Allocated to Group I and Group II

	Group I	Group II	P
Sex (female:male)	12:8	13:8	0.577
Age (years)	10.2 ± 1.0	10.3 ± 1.1	0.784
Nail status (%)	71.3 ± 7.2	71.7 ± 5.3	0.836
Anxiety score	27.40 ± 4.37	28.14 ± 3.38	0.545
SGI	1.01 ± 0.18	1.01 ± 0.16	0.994
SPI	2.12 ± 0.29	2.10 ± 0.28	0.884

SGI, simplified gingival index; SPI, simplified plaque index.

The outcomes of all children recruited for the study are presented in Figure 3. At visit 1, 42 students were allocated to group I and 41 to group II. Two children failed to complete Method A, and three failed to complete Method B during the first period of the study. After a 2-month washout period, 18 students allocated to group I and 13 students allocated to group II did not meet the inclusion criteria because their NS had recovered. In addition, one student allocated to group I and two students allocated to group II dropped out. Therefore, at the next visit, the remaining 21 students allocated to group I began Method B, and 20 of them finally finished. Two of the remaining 23 students allocated to group II dropped out, so 21 students finally finished both methods in group II. A total of 41 (49%) of the 83 students recruited completed both treatment arms and attended all appointments (Fig. 3), exceeding the estimated number (11/group) needed to detect a significant difference. There were no skin symptoms or major discomfort due to auricular acupressure at any time during the study, and none of the patients dropped out because of issues with the acupressure treatment.

FIG. 3.

The participant flow throughout the study. “Dropped out” indicates children who did not show up for their treatment or changed their mind about participating.

The anxiety score and NS for all participants being treated using Methods A and B were significantly different (p < 0.001), and the SGI also showed significant differences between the two methods (p < 0.05), with more favorable effects for Method A (acupressure with anxiety-reducing effects). However, there were no significant differences in the SPI between the two methods (p = 0.685) (Table 2).

Table 2.

Comparison of the Outcomes of the Two Different Methods

Item	Method A	Method B	P
Nail status (%)	17.3 ± 7.1	11.6 ± 8.2	0.000^*
Anxiety score	7.00 ± 3.37	2.76 ± 3.38	0.000^*
SGI	0.54 ± 0.26	0.40 ± 0.22	0.023^*
SPI	0.14 ± 0.42	0.10 ± 0.36	0.685^*

p < 0.05 for comparisons of the baseline versus endpoint.

SGI, simplified gingival index; SPI, simplified plaque index.

The NS, anxiety score, SGI, and SPI for groups I and II (where the order of Methods A and B were reversed) are shown in Figure 4A–D. As in the overall comparison, there were significantly better scores for Methods A for the NS, anxiety score, and SGI compared to baseline (p < 0.001), regardless of the order in which the method was used. Again, the SPI did now show any significant difference between the baseline and endpoint for either group.

FIG. 4.

A comparison of the two groups (Group I: Method A then Method B; Group II: Method B then Method A). The data shown are for the (A) nail status, (B) anxiety score, (C) simplified gingival index, and (D) simplified plaque index.

Discussion

Although both methods could improve the status of the nail, reduce the SGI, and improve the patients' anxiety, there were significant differences between Methods A and B. This means that the use of auricular acupressure during HRT can better reduce anxiety and increase the efficacy of treatment. Of note, Method B also showed small reductions in the anxiety of nail biters. A parent was identified to support each child to improve treatment adherence during HRT, and this increased attention and support may have reduced the children's anxiety. Another possible reason was the physiologic effects of acupressure. Although the points used for the “placebo” acupressure have not been reported to reduce anxiety, their stimulation may have had soothing effects and improved the well-being of the participants, thus reducing anxiety.

The SPI did not show any significant differences between the methods, nor between the baseline and endpoints. This may be because the SPI is affected by the frequency and efficacy of tooth brushing, the hardness and viscosity of food consumed, and other factors (such as chewing gum), making it more apt to fluctuations. This high level of fluctuation likely led to the lack of significant differences. Although prohibiting candy consumption and gum chewing and requesting that patients brush their teeth every 12 hours might help to reduce the variability, it is likely that dietary differences would still lead to fluctuations in the SPI.

The chief complaints of the nail biters who visit the Department of Stomatology include gingival discomfort, dental caries, malocclusion, and bruxism. These are difficult to resolve when subjects continue their nail-biting habit. This is because children who bite their nails are exposed to the nails and nail fragments, which contain a variety of pathogenic bacteria, and may become lodged in or between the teeth or gums. In addition, frequent nail biting may make the mouth dry, decreasing the integrity of the oral mucosa and making it less resistant to pathogenic bacteria.²⁴ This would be accompanied by an increase in salivary viscosity and a lack of tooth surface self-cleaning, so the accumulated pathogenic bacteria would more easily cause gingivitis.²⁵ Therefore, we believe that the SGI is a good indicator of the patient's oral health and their nail-biting status.

Better habit resolution was associated with lower anxiety in the children, consistent with previous research²⁶ showing that anxiety reduction had positive effects on nail biting. Anxiety disorders are the most common psychiatric diagnosis in patients between 6 and 18 years of age.²⁷ Therefore, while some oral habits, including nail biting, are known to be harmful habits, they may serve an adaptive function to overcome anxiety.⁶ Our findings suggest that providing anxiety relief can help to rectify the nail-biting habit more effectively than HRT alone. Nevertheless, while auricular acupressure accelerated the habit correction, the habit reversal treatment was the major reason for the improvement, and we do not believe that anxiety reduction alone would be sufficient to correct a nail-biting habit.

Auricular acupressure involves the stimulation of specific acupoints of the ears to diagnose and cure physical and psychosomatic dysfunctions.²⁸ The mechanisms of action²⁹ involve the connection between the auricle and autonomic nervous system and have been described by delta reflex theory and experiences with functional magnetic resonance imaging. Its antipsychogenic effects have been suggested for the reduction of anxiety and depression. The Triple Heater (Sanjiao) area³⁰ is a major area used for diagnosing and treating stress responses related to important life events, so we adopted this point (MA-IC4), in addition to a sympathetic point (MA-AH7), heart point (MA-IC), the Shenmen point (MA-TF1), and an adrenal gland point (MA-TG), to reduce anxiety in our study. Although the stimulation of our selected points significantly reduced anxiety and improves the outcome of HRT, it is possible that there may be other combinations of points that might lead to even stronger effects, such as the Relaxation, Tranquilizer, and Master Cerebral points examined by Wang and Kain in several studies^13,14 Future studies will be needed to determine the optimal combination of auricular acupressure points.

It is also possible that a different washout period may have led to differences in the apparent efficacy of the approaches. However, two of the endpoints (gingival index and nail status) had returned almost to the baseline by the end of the washout period, and the other two showed some return toward the baseline. We therefore believe that the washout period between arms was appropriate and allowed for an adequate assessment of the efficacy of the two treatments.

There are several reasons why we chose to use magnetic seeds for our patients. First, magnetic seed acupressure is already being promulgated as a nonpharmacological and low-risk therapy for anxiety.^31,32 Second, these seeds are small, inexpensive, and easy to apply. Thus, any dentist, nurse, or parent can perform the treatment without assistance or the need for complex and costly devices. Minimal training is needed to learn the specified points to apply the treatment. Third, dentists and parents who have little or no experience in traditional Chinese medicine can learn the technology in a few hours and use it whenever indicated.

Conclusion

This study showed that both Method A and Method B helped to improve the NS and reduce the SGI of nail biters undergoing HRT, but Method A (anxiety-reducing auricular acupressure) more effectively reduced the levels of anxiety in nail biters, and showed significantly better outcomes than Method B. The reduced anxiety made it easier for the patients to cease their pernicious habit, even when they had already failed treatment with HRT plus “placebo” acupressure. Further studies are needed to determine how to best apply this treatment to provide the greatest improvements in the subjects' mental and physical health, and to determine whether the treatment results in long-term cessation of the harmful habit.

Footnotes

Acknowledgments

The authors' thank the children who took part in this study, their parents, and the staff. This work was supported by grants from the Natural Science Foundation of Xinjiang Uygur Autonomous (2018D01C208).

Author Disclosure Statement

No competing financial interests exist.

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