Psychometric Assessment of Clinical Factors in Burning Mouth Syndrome Progression

Abstract

Objective

This study employed psychometric tools to assess the impact of factors such as age, symptom location, and duration on the improvement in burning mouth syndrome (BMS).

Materials and Methods

A total of 86 women with BMS were divided into 4 groups: laser plus clonazepam (n = 24), sham laser placebo (n = 20), laser only (n = 22), and clonazepam only (n = 20). Symptom severity was measured using the Visual Analog Scale (VAS), while depression and anxiety were evaluated using the Hospital Anxiety and Depression Scale (HADS). Stress levels were assessed using the Perceived Stress Scale (PSS) and somnolence with the Epworth Somnolence Scale (ESS). Questionnaires were completed at baseline, 1 month post-treatment, and at 3 months of follow-up.

Results

Symptom intensity significantly decreased from baseline to study end (P < .001), with minor increases during follow-up. Stress levels also significantly declined (P = .016), while anxiety, depression, and somnolence showed no significant changes (P > .05). Symptom intensity correlated with age (P < .001), and initial anxiety correlated with disease duration (P = .027).

Conclusion

Age, disease duration, and symptom location did not significantly influence symptom improvement, psychological state, or somnolence. Further multidisciplinary research is needed.

Introduction

According to the International Headache Society (IHS), burning mouth syndrome (BMS) is a complex chronic orofacial pain disorder characterised by an intraoral dysesthesia, or burning sensation, that lasts for more than 2 hours every day for at least 3 months without any objective proof, such as mucosal lesions or test results.^1,2 The burning sensation usually manifests in several areas of the mouth, including the lips, gums, and, more often, the tongue.³ These patients usually have a lower quality of life and higher levels of psychological stress.⁴

Based on a recent meta-analysis study, 0.1%-3.9% of the general population has BMS,⁵ and it appears to affect women more often than men (1.15% versus 0.38%),⁶ particularly among postmenopausal women aged 50 to 70.⁷

Currently, its etiopathogenesis is still a challenge for health professionals, as it is not very precise. A multifactorial etiological character has been proposed that includes the participation of local, systemic, and psychological factors.⁸ As a result, different hypotheses have been proposed. The first suggests that BMS is neuropathogenic, indicating a dysfunction of the central and peripheral nervous system pathways.⁹ The second refers to the hormonal factor, given that this syndrome is strongly present in menopausal and postmenopausal women.¹⁰ The third considers psychological factors, with some studies associating a state of psychological alteration with an exacerbation in the intensity of symptoms in chronic pain conditions.¹¹ Numerous studies have examined the influence of psychological aspects, demonstrating that BMS has an impact on patients' quality of life¹² because they often experience depression, anxiety,¹³ and stress,¹⁴ and their state of somnolence is also altered.¹⁵

With respect to the treatment of patients with BMS, no global guidelines exist. Its pathogenesis is not very well understood, with an inconsistent and limited response to diverse treatments observed.¹⁶ In addition, it has a prevalence of spontaneous remission that is extremely low, from 3% to 4%, 5 to 6 years after the initial diagnosis.^17,18 Therefore, when patients are not able to find efficient treatments, they start to feel desperate with respect to the management of pain, resulting in a state of anxiety/depression.¹⁹

What seems to be clear is the need for a multifactorial treatment that considers all the previously mentioned factors, as well as the characteristics of each patient,²⁰ and contains an extensive medical history; a neurological, cardiovascular and psychiatric/psychological assessment; and an oral cavity examination with an emphasis on the oral mucosa and dental issues.¹

This current study is based on a prior investigation that evaluated the effectiveness of clonazepam and low-intensity laser therapy for BMS.²¹ Specific aspects are addressed that were not previously explored, such as the impact of clinical factors (age, location, and time progression) on the improvement of symptoms. Thus, this study provides a complementary approach to understanding BMS. The aim of this study was to analyse the influence of clinical factors such as age, duration of symptoms, and location of the burning sensation on the progression of pain, perceived stress, depression, and somnolence of patients with BMS during treatment and at 3-month follow-up, using validated psychometric tools.

Materials and methods

Study design and patient selection

The present study was conducted with 90 patients (95.56% women and 4.44% men) who attended the University Clinical Hospital Morales Meseguer, located in the Region of Murcia (Murcia, Spain), to be treated at the Department of Oral Medicine during the 2021-2023 period. The patients were divided into four randomly selected groups, and each group received a different treatment. All the participants were informed about the study and provided their consent to participate in it after approval from the Ethics and Biosafety Committee of the University of Murcia, Spain (ID: 407/2021). The study follows the Helsinki Declaration from the World Medical Association (WMA).

The inclusion criteria were the following: patients older than 18 years of age diagnosed with BMS according to the IHS definition² with symptoms of continuous burning and stinging sensations without a justified cause for at least 6 months bilaterally in the oral cavity and without clinical alterations in the oral mucosa. Patients were excluded if they needed changes in any of the systemic medications, as were patients who were taking antidepressants, antipsychotics, or antiepileptics, as well as pregnant or lactating patients, oncology patients, or patients with pre-existing diagnosed psychiatric comorbidities. To control for the hormonal factor, a decision was made to not include the small group of men (n = 4). This was done to make the sample more uniform.

Patient assignment to each group was performed on a blind basis using a random sequence-generating program (https://www.randomizer.org). The sealed and numbered envelopes containing group assignments were prepared by a team member not involved in patient enrollment or treatment. The envelopes were opened sequentially only after each patient was registered in the study. The following is how the patients were being treated in various groups:

• -Group 1 (n = 24): patients received 0.25 mg of clonazepam (for 1 month, 1 dose per day, taken at night by dissolving the tablet in the mouth for 1 minute and spitting it out without ingesting) and, simultaneously, a low-intensity diode laser treatment once a week for a month. For low-level light therapy (LLLT), the Helbo Theralite Laser 3D Pocket Probe (Bredent Medical GmbH & Co) was used, following the manufacturer’s instructions, to treat each zone of the oral cavity that presented symptoms, allowing it to act for 30 seconds per light spot (active surface area 19 mm²; energy density = 30 s × 200 mW/cm² = 6 J/cm²).
• -Group 2 (n = 20): patients received the same laser treatment but as a placebo (once weekly for a month); the laser tip was not activated.
• -Group 3 (n = 22): patients received simple laser treatment (LLLT) once a week for a month.
• -Group 4 (n = 20): for a month, once a day, patients received only 0.25 mg of clonazepam, which they took at night by dissolving the tablet in their mouth for 1 minute and spitting it out without swallowing.

A follow-up was performed with all subjects after the treatment, which consisted of 2 follow-up appointments. The first appointment took place 1 month after the treatment, and the second appointment took place 3 months after the treatment. During each session, patients were once again asked to complete questionnaires to assess the intensity of the burning sensation, stress, anxiety, depression, and somnolence. The four groups that formed the structure of the study were unknown to the patients. The evaluator, although not blinded, did not influence the patients' responses to the various questionnaires.

Data collection

A single qualified professional (AGM) evaluated the participants and took a thorough clinical history of each patient, including sociodemographic information and clinical data (age, diseases, medication, and the first signs of BMS symptoms). Each patient had an extraoral and intraoral examination to determine the areas where they displayed BMS symptoms. They were also given a schematic picture to help them point to and record the area more precisely.

At each of the appointments, the following questionnaires were provided (Figure 1):

• -Visual Analog Scale (VAS): a 10-point scale to determine the intensity of the symptoms, with 0 meaning the absence of pain and 10 meaning maximum pain possible. This scale is fundamental for objectively qualifying the increase or decrease of the symptoms.²² The patients indicated their level of intensity before receiving the treatment, after ending the treatment sessions, and at 3-month follow-up.
• -Hospital Anxiety and Depression Scale (HADS): a self-completed questionnaire of 14 items with 2 subscales, one that refers to depression (D) and another to anxiety (A), with 7 items each.²³ The range of scores for each subscale is 0 to 21 points. A higher score indicates a higher level of depression and anxiety. For each subscale, scores >8 are considered pathological.²⁴ The patients indicated their state of anxiety and depression at the first appointment, 1 month after finishing the treatment, and at 3-month follow-up.
• -Perceived Stress Scale (PSS): a self-report instrument that assesses the level of stress perceived in the past month.²⁵ It is composed of 14 items with a 5-point Likert scale (0 = never, 1 = almost never, 2 = sometimes, 3 = often, and 4 = very often). The total PSS score is obtained by inverting the scores of items 4, 5, 6, 7, 9, 10, and 13 (in the following manner: 0 = 4, 1 = 3, 2 = 2, 3 = 1, and 4 = 0) and adding the scores for all 14 items. A higher score corresponds to a higher level of perceived stress.²⁶ The patients answered this questionnaire at the first appointment, 1 month after the treatment ended, and at 3-month follow-up.
• -Epworth Somnolence Scale (ESS): a scale composed of 8 questions with 4 answers for each question and scored from 0 to 3 points. The total score can range between 0 to 24 points, and the results are defined as follows: 1-6 = normal sleep, 7-8 = medium somnolence, and 9-24 = anomalous somnolence. This test was also answered by the patients at the first appointment, 1 month after finishing the treatment, and 3 months post-treatment²⁷ (Figure 1).

Fig. 1.

Diagram of data collection using questionnaires.

Finally, to study the improvements observed during the treatment, once the scores from each questionnaire were recorded (initial, final, and after 3 months), the improvements were calculated as differences in the following manner:

• -Improvement at the end: the difference between the final value (1 month after the treatment) and the initial value (at the start of the treatment).
• -Improvement at follow-up: the difference between the follow-up value (after 3 months) and the initial value (at the start of the treatment).

Statistical analysis

The program used for the statistical analysis was IBM SPSS statistics (version 19, 2010). The variables were described with frequencies (n) and percentages (%), or with mean values (M) and standard deviations (SD). The normality criteria used were Shapiro-Wilk (W). The relationships between the parametric variables were analyzed with Pearson’s test (r) and the comparison between means with Student’s t-test (t) or with ANOVA. Non-parametric variables were analyzed with Spearman’s test (p, Rho) and the comparison between means with the Mann-Whitney test (U) or with the Kruskal-Wallis test (H). The relational analysis between ordinal and qualitative values was performed with Pearson’s chi-square test (χ²). In all cases, a risk of 5% (α = .05) was considered.

Results

Table 1 shows the age, disease progression time, and location of the symptoms in the patients. The most common location of the symptoms pointed out by the patients was the tongue (90.7%).

Table 1.

Main study variables.

MAIN STUDY VARIABLES
Age (years) m ± SD		63.0 ± 10.7
Mean duration of the diseases (years) ± SD		4.9 ± 3.1
Location of symptoms
Tongue n (%)			Palate n (%)
No	8 (9.3)		No	44 (51.2)
Yes	78 (90.7)		Yes	42 (48.8)
Lips n (%)			Gums n (%)
No	40 (46.5)		No	55( 64.0)
Yes	46 (53.5)		Yes	31 (36.0)

%, percentage; m ± sd, mean ± standard deviation; n, frequency.

Table 2 shows the answers to the different questionnaires, showing that the levels of symptoms intensity perceived (VAS) at the start of the treatment were high, gradually decreasing at the 1-month review. However, at 3 months, a slight increase was observed. The intensities reported at the several post-treatment appointments showed a significant difference (P < .001) when the means were compared.

Table 2.

Responses to questionnaires on symptom intensity (VAS), anxiety/depression (HAD), stress (PSS) and somnolence (ESS) during the study.

ANSWERS TO THE QUESTIONNAIRES
Variables	Initial (m ± SD)	Final (m ± SD)	Follow-up at 3 months (m ± SD)	P
Intensity (VAS)	8.1 ± 1.5	5.7 ± 2.9	6.0 ± 2.9	< .001
Anxiety (HAD)	7.2 ± 5.5	7.2 ± 5.9	6.6 ± 5.6	.489
Depression (HAD)	10.0 ± 4.2	9.8 ± 5.0	9.9 ± 5.6	.454
Stress (PSS)	28.8 ± 9.3	26.7 ± 10.4	26.2 ± 11.0	.016
Somnolence (ESS)	6.4 ± 4.7	6.4 ± 4.5	6.0 ± 4.4	.891

m ± SD, mean ± standard deviation; P, significance value (bold values indicate significant differences).

There was a significant difference (P = .016) between the 3 periods of evaluation for the stress perceived (PSS), with improvements seen in the assessments at the end of the therapy and the follow-up phase after 3 months.

The findings of the correlation analysis among the main study variables (MSVs) are displayed in Table 3. These come from a joint study, without differentiating between treatments. It was found that Age and Progression time were more related to the perceived pain intensity (VAS) compared to other variables. Anxiety is significantly influenced by the Progression time; a longer duration may be associated with lower initial and 3-month anxiety levels.

Table 3.

Results of the analysis of the relationship between the main study variables and the age of the participants, time of evolution and number of affected areas.

Main Study Variables	Age ρ (P)	Progression Time ρ (P)	Number of Areas Affected ρ (P)
VAS, Session 1	.45 <.001	.25 .026	.06 .597
VAS, 1-month follow-up	.29 .009	.32 .005	-.02 .860
VAS, 3-month follow-up	.35 .002	.35 .002	-.01 .930
Initial anxiety (HAD)	−.06 .576	−.25 .027	.05 .636
Final anxiety (HAD)	−.08 .461	−.21 .062	<.01 .994
Anxiety at 3-month follow-up (HAD)	−.03 .775	−.24 .042	−.02 .857
Initial depression (HAD)	<-.01 .970	−.17 .128	.04 .724
Final depression (HAD)	−.05 .656	−.12 .279	.07 .534
Depression at 3-month follow-up (HAD)	.02 .876	−.10 .395	03 .824
Initial stress (PSS)	−.15 .170	−.19 .089	.09 .424
Final stress (PSS)	−.17 . 134	−.15 .204	.08 .503
Stress at 3-month follow-up (PSS)	−.14 .233	−.15 .215	.01 .955
Initial somnolence (ESS)	−.08 .453	.02 .831	.16 .138
Final somnolence (ESS)	−.05 .663	.04 .756	.17 .140
Somnolence at 3-month follow-up (ESS)	−.07 .536	.07 .554	.15 .191

α Risk = .05. ρ, Spearman’s Correlation Index; P, significance value (values in bold indicate significant differences).

It appears that none of the variables being measured are significantly impacted by the number of affected locations.

Table 4 presents the analysis of potential differences in MSV improvement based on age. Two age groups were created using the median as the cut-off point.

Table 4.

Comparisons of improvements in the MSV based on ages, progression time, and number of affected areas (according to the final improvement and improvement at follow-up).

Main Study Variables	Age				Progression Time				Number of Areas Affected
	Levels	M	SD	U (P)	Levels	m	SD	U (P)	Levels		m	SD	U (P)
Final VAS improvement	≤64 years old	−1.94	2.28	615.00 .740	≤ 4 years old	−2.13	2.42	547.00 .483	≤2 affected areas	−2.00		2.35	574.00 .734
	>64 years old	−1.82	2.28		>4 years old	−1.72	2.19		>2 affected areas	−1.75		2.17
Improvement in VAS at follow-up	≤64 years old	−2.00	2.29	578.00 .348	≤ 4 years old	−2.26	2.39	495.00 .135	≤2 affected areas	−1.74		2.33	606.50 .841
	>64 years old	−1.55	2.24		>4 years old	−1.48	2.11		>2 affected areas	−1.83		2.21
Final Anxiety improvement (HAD)	≤64 years old	−0.15	1.87	828.50 .925	≤ 4 years old	−0.24	2.13	694.50 .477	≤2 affected areas	−0.06		1.80	800.00 .878
	>64 years old	0.14	1.98		>4 years old	0.07	1.76		>2 affected areas	0.06		2.12
Improvement in Anxiety at follow-up (HAD)	≤64 years old	<0.01	2.25	713.50 .821	≤ 4 years old	−0.32	1.92	651.00 .861	≤2 affected areas	−0.28		2.13	627.50 .361
	>64 years old	0.02	2.20		>4 years old	<0.01	2.12		>2 affected areas	0.45		2.29
Final Depression improvement (HAD)	≤64 years old	0.00	1.76	743.50 .369	≤ 4 years old	−0.29	1.84	731.00 .732	≤2 affected areas	−0.46		1.68	672.00 .168
	>64 years old	−0.30	1.99		>4 years old	−0.09	1.99		>2 affected areas	0.21		2.13
Improvement in Depression at follow-up (HAD)	≤64 years old	0.06	2.90	0.27* .788	≤ 4 years old	−0.26	3.09	−0.42* .677	≤2 affected areas	−0.19		2.44	−0.49* .627
	>64 years old	−0.12	2.80		>4 years old	0.02	2.70		>2 affected areas	0.13		3.36
Final Stress improvement (PSS)	≤64 years old	−1.69	3.75	732.50 322	≤ 4 years old	−2.97	4.25	597.00 .095	≤2 affected areas	−2.46		4.36	715.50 .342
	>64 years old	−2.42	4.42		>4 years old	−1.58	3.98		>2 affected areas	−1.47		3.74
Improvement in Stress at follow-up (PSS)	≤64 years old	−1.94	4.41	−0.68* .496	≤ 4 years old	−2.84	4.94	−1.08* .286	≤2 affected areas	−2.15		4.97	−0.32* .753
	>64 years old	−2.05	4.94		>4 years old	−1.66	4.49		>2 affected areas	−1.81		4.23
Final Somnolence improvement (ESS)	≤64 years old	0.03	.78	733.00 .245	≤ 4 years old	0.21	0.91	715.00 .562	≤2 affected areas	0.10		0.93	789.00 .763
	>64 years old	0.23	1.04		>4 years old	0.09	0.97		>2 affected areas	0.18		0.94
Improvement in Somnolence at follow-up (ESS)	≤64 years old	−0.08	.97	732.00 .765	≤ 4 years old	−0.06	1.15	634.50 .531	≤2 affected areas	−0.06		1.01	681.00 .547
	>64 years old	0.07	1.07		>4 years old	0.05	0.96		>2 affected areas	0.10		1.04

^⁎Student’s t-test (t). α Risk = .05. m, mean; P, significance value (values in bold indicate significant differences); SD, standard deviation; U, Mann-Whitney test.

Significant statistical differences were not found in any of the MSVs based on age. For the two types of improvements in the VAS (final and follow-up), age was not a significant differentiating factor. The improvements in both age groups were comparable, with a slight tendency towards greater improvement in the ≤64 years group, although it was not enough to be statistically significant.

When analysing the possible differences in the improvements of the MSV based on the disease progression time (Table 4), the length of time that the disease progressed did not significantly affect any of the MSV improvements. Lastly, when evaluating the possible differences in the improvements of the MSV based on the affected areas of the mouth (Table 4), there were no apparent differences in any of the MSV improvements related to the location of symptoms in the mouth.

Discussion

The chronic condition known as BMS mostly affects women. The treatments used have a limited response and are typically not wholly successful due to the affliction’s complex aetiology, which includes psychological, systemic, and local factors.¹⁶ It has been demonstrated that BMS is linked to anxiety, depression, and stressful life events. Addressing these conditions can lessen or enhance pain perception.²⁸

In the present study, a significant difference (P < .001) was found between the intensity of the symptoms measured with the VAS in the different appointments and the perceived stress (PSS) in the three periods of assessment. No differences were found in anxiety, depression, or somnolence during the period of study. However, the study by Tan et al. showed significant differences in the intensity of the symptoms (measured with the VAS) and in psychological factors such as stress, anxiety, or depression, with significant differences found before and after the treatment, highlighting the results found with Clonazepam and Pregabalin.¹⁶ The differences between the two studies may be attributable to various factors, such as specific characteristics of the populations studied, the methodologies used, or the duration and approach of the applied treatments.

On the other hand, age was found to be significantly and directly correlated with the severity of symptoms before therapy (P < .001), 1 month post-therapy (P = .009), and 3 months post-therapy (P = .002) in the current study. Thus, according to the results, the older the patient, the greater the intensity perceived. Okayasu et al. found that groups of women of various ages were sensitive to tongue pain, with the level of pain measured using the Numeric Rating Scale (NRS). The findings showed that younger and older women's perceptions of pain did not differ significantly.²⁹

It is still debated whether psychological factors are a primary cause or a consequence of BMS, given that chronic pain can alter a person’s psychological profile. However, the physiopathology of BMS may involve depression and anxiety. When comparing BMS patients to healthy volunteers, Schiavone et al. revealed notable disparities. The somatisation and hostility dimensions scores of BMS patients in that study were greater than those of the control group.³⁰

No significant associations were found between age and improvements in intensity, psychological variables, or somnolence throughout the course of treatment and follow-up. Although a direct correlation between age and improvement was not established in the retrospective study by Chimenos-Küstner, the findings highlight the significant impact of psychological factors and sleep quality on patient prognosis.³¹

On the other hand, we observed that the disease progression time was positively and directly related to the intensity of the perceived pain at the first session before the treatment (P = .026), a month after treatment (P = .005), and at 3-month follow-up (P = .002). The perceived intensity increases with the length of time the condition progresses. The authors of the study by Canfora et al. which examined the use of self-reported questionnaires to analyse the aspects of pain and correlate them with the psychological profile of patients with BMS, explained that patients with a longer progression time reported a higher perceived intensity because of the delay in the syndrome's diagnosis and the persistence of long-term pain that was either untreated or undertreated and did not improve.³²

It was also observed that there was a significant and inverse relationship between anxiety (initially measured (P = .027) and at 3-month follow-up (P = .042)) and disease duration. People who have had the disease for a longer time have less anxiety (this is referred to as the habituation phenomenon). Younger patients who have had the disease for less time consequently have less knowledge of the disease and its symptoms and, therefore, feel more anxious.³³

When correlating the progression time with the improvements found in the main study variables, there were no discernible relationships between intensity, anxiety, sadness, perceived stress or somnolence at the beginning of therapy and at the 3-month follow-up. According to a study by Adamo et al., anxiety and depression are related, and both have a major effect on sleep. However, the researchers stated that somnolence needs to be considered a separate factor because it may have started before the BMS symptoms. Furthermore, a significant difference between the BMS group and the control group was observed when somnolence was measured using the ESS. This difference was stronger in patients with the disorder.³⁴

No significant differences were observed in the number of areas in the mouth affected by the symptoms when comparisons were made. The patients reacted equally when having a higher or lower number of affected areas. Patients considered the oral cavity as a single source of symptoms, and it affected them equally with respect to the perceived intensity, anxiety, depression, stress and somnolence. The study by Ozasa et al. examined the predictive power of anxiety and depression on conditioned pain modulation, in which a painful heat stimulus was delivered to the tongue, by using the State-Trait Anxiety Inventory. According to the findings, patients with BMS had higher scores than the control group because the anxiety trait had a detrimental effect on the body's natural pain modulation mechanism.³⁵

A comparison between BMS patients with and without psychiatric issues was done in the Kim et al. With respect to age, it was observed that the group with psychological pathology was older than those who did not have this pathology. The patients with psychological problems also reported higher scores on the intensity levels in the visual analog scales. In addition, the mean progression time was longer in the group with psychological problems when compared to the group without them. Lastly, the patients with a higher number of affected mouth areas were also the group with more psychological disorders.³⁶

Forsell et al.'s article examined the relationship between a patient's psychological condition and the intensity of their symptoms by assessing them using the Pain Vigilance and Awareness Questionnaire, the Depression Scale and the Pain Anxiety Symptom Scale. The results demonstrated that patients with higher symptom intensity also reported higher levels of anxiety and depressive symptoms because of the pain, as well as higher levels of concern, compared to those with lower symptom intensity.³⁷

Both the nature of the subject and the limitations of current research methods place certain constraints on this investigation. In this study, we did not stratify the results based on treatment type. Instead, our goal was to assess the overall psychological response of patients simply from receiving professional care. As noted in the literature review by Khemiss et al., the placebo effect alone can sometimes produce benefits comparable to those of active treatments.⁷ On the other hand, the use of subjective instruments such as anxiety, depression and somnolence questionnaires or scales depends on the self-assessment of the patient, which can introduce response biases. The lack of standardisation in studies that use different methods to assess the psychological component and the pain intensity makes it difficult to compare the results. In addition, there is a lack of longitudinal studies that perform an in-depth analysis of the progression of BMS. Finally, the size of the sample and the limitations in the recruitment of patients who were committed to the follow-up appointments, even without optimum results, made statistical validity more difficult. Although the population most affected by BMS are women,³⁸ one limitation of the study was that male participants were excluded after an initial review. This was done to make the sample more uniform. However, a better approach might have been to stratify the groups by sex or match them by age. As a result, the ability to apply the findings to a wider population is limited.

Conclusion

The results suggest that age, the progression of BMS and the number of areas in the mouth with symptoms did not affect the improvement of the pain intensity, the psychological state or the somnolence perceived by the patient.

More objective tools (e.g. stress-related biomarker studies or neurophysiological investigations) and a bigger sample size are required for longitudinal research that will elucidate better the link between BMS and psychological conditions. In addition, a better study design must be sought and standardised in which the assessment and treatment of the psychological problems of patients with BMS play a fundamental role, using a multidisciplinary approach.

Funding

The authors declare that they have not received any funds, grants, or other financial support.

Conflict of interest

The authors declare no competing interests.