Assessment on interoceptive awareness on alcohol use and gambling disorders reveals dissociable interoceptive abilities linked to external and internal dependencies: Practical use of Body Perception Questionnaire Very Short Form (BPQ‐VSF) in clinical settings

Abstract

Interoception is one of the pivotal cognitive functions for mechanisms of our body awareness, and malfunction of the interoceptive network is thought to be associated with mental illness, including addiction. Within addictive disorders, substance‐based and non‐substance‐based addictions are known to hold dissociable reward systems. However, little is known about how interoceptive awareness between these addiction sub‐types would differ. Subjective interoceptive awareness was assessed among patients with alcohol use disorder (n = 50) who were subsequently hospitalized or remained out‐patient and gambling addiction (n = 41) by the Body Awareness component of the Japanese version of the Body Perception Questionnaire (BPQ‐VSFBA‐J) and compared them against healthy control (n = 809). Both addiction groups showed significantly lower BPQ than the control, with no substantial differences between inpatients and outpatients for alcohol samples. Notably, BPQ scores for gambling patients were significantly lower than those for the alcohol group. This evidence may suggest a putative role of interoceptive ability on the severity of behavioral addiction over substance‐based addiction.

INTRODUCTION

Interoception is the ability to perceive and interpret body signals such as reflexes, drives, cravings, and emotional experiences. Some of these are included but not limited to hunger cues, pain, and arousal drive changes. A homeostatic measure by the mind and body interplay, interoception, is reportedly a key function in the study of addictive behaviors and disorders. The changes in interoceptive sensitivity are profound among mental disorders.¹ To date, different methods have been proposed to assess this interoceptive awareness. Measurements of interoception make up different dimensions of its perception. As an index for interoceptive awareness, interoceptive sensitivity reflects an individual's ability to accurately perceive and interpret the sensations occurring within their body.² However, theoretical representations of interoception go beyond the basis of emotion and extend to reward-seeking decision-making, sense of self, cognitive contribution to emotional experience, and even learning processes.²

Neural underpinnings of interoception

Interoceptive processes involve several cortical and subcortical areas, so-called interoceptive networks, such as the thalamus, anterior cingulate, orbitofrontal, and medial prefrontal cortices.^3,4 Among the widely spread network, the insula works largely with the anterior cingulate cortex to pass along salient stimuli and limbic affective information between the default mode and salience networks; the stronger the network connection, the more accurate information can be identified.⁵ Not only functions of the network but also cortical anatomy centered around the insula are also associated with interoceptive awareness⁶ in line with hierarchical architectural formation within the insula cortex.⁷ When altered due to substances, such as alcohol, increased activity happens within these networks – notably the salience network – including the insular and cingulate cortices and the striatum.⁵ When tested on animals to ascertain discriminatory interoceptive effects, researchers found that alcohol specifically inhibits excitatory neurons (glutamate) and potentiates inhibitory neurons (GABA), with serotonin receptors also being implicated in interoceptive sensitivity.⁵ The insula also plays a role in reward-seeking decision-making such that patients with focal insular lesions were less affected by the degree of uncertainty while participating in gambling tasks.⁸ Nevertheless, the insula is vital to processing physiological cues and plays a fundamental role in interpreting subjective emotional experiences and higher cognitive functions such as emotional² (Murch & Clark, 2016).⁸

Interoception on mental health

Over chronic substance use, the insular cortex can be physically altered, and as it contains overlapping neural circuitry with control, salience assessment, and reward processing, it makes a prime subject for studying addictive behavior and thought.⁹ According to the Genetically Informed Neurobiology of Addiction model (GINA), addicted individuals experience three separate stages of addiction as neurological changes occur in the corticostriatal and corticolimbic circuitry due to chronic substance abuse.¹⁰ These are the binge-intoxication stage, the withdrawal-negative affect stage, and the preoccupation-anticipation stage. During binge intoxication, consumption of the substance leads to large releases of dopamine in the nucleus accumbens, positively reinforcing the substance use's physiological feeling and mimicking reward signals.¹⁰ The anterior system of the insula also contributes to memory and predictive reward cues surrounding substance use,¹¹ internalizing both external and internal cues regarding substance use and the circumstances surrounding it. However, aversive physiological and psychological withdrawal symptoms lead to stronger negative reinforcement of substance use to alleviate symptoms and reinstate homeostasis within the body, therefore setting the neural framework to adapt the influenced state as the homeostatic baseline.¹⁰

As the body adjusts to substance consumption over time, the amount needed to achieve desired pleasure or homeostasis increases, and more neurological damage occurs.¹¹ As damage to the insula occurs, the accuracy of both physiological and psychological interoceptive cues (such as alexithymia in cases of Alcohol Use Disorder, AUD) diminish, further leading to increased cravings for the substance and enabling frequent substance use.¹² In the case of gambling disorder, damage to the insula, along with the posterior parietal cortex, resulted in riskier betting behavior through changing bet size in order to achieve greater feelings of reward (Clark & Murch, 2016), further displaying the adjustment of reward and motivational cues outside of a substance-based addiction setting.

Alcohol use disorder

AUD is one of the major addictive disorders that are dependent on a substance, alcohol. Direct linkage between interoceptive abilities and the heart-brain regulatory system plays a large part in the interoceptive ability within those with AUD and those with the disorder scored higher on interoceptive sensitivity than they did with interoceptive accuracy in regard to physiological heart functioning tracking.⁹ As alcohol interrupts heart function on the physiological level, it also interrupts the interoceptive processes and modulates their functionality.¹³ The physiological effects of alcohol can be discriminatory in accordance with usage and subsequent tolerance levels, such as slurring words, losing balance, lethargy, etc.⁵ These stimuli later translate into interoceptive ability and changes within the insular cortex due to larger amounts of consumption to achieve homeostasis. Physiologically, negative and positive interoceptive states can affect the consumption habits of those with AUD, making consumption habits largely indiscriminate but tied to reducing negative affect and boosting positive affect.⁵ These states are the underlying motivation for those with AUD. Among AUD, interoception also plays a role in emotion recognition and perception.¹⁴

Gambling disorder

GD is a form of behavioral addiction; patients with GD depend on the behavioral process. Gambling's addictive effects differ from those of substances in the absence of actual physical consumption. Rather, it is entirely based on the effects of actual behavior-derived chemical reactions. Yet, gambling holds pathological similarities to those of substance use disorders and has neurobiological overlap.¹⁵ A large component of gambling is risky behavior, specifically within that decision-making between any choice and predicting its possible outcome. With gambling behaviors come their own distinctive psychological and cognitive models, one example of which is gambler's fallacy: a bias in the processing of random sequences and expected outcomes of certain events, most prominently displayed within the casino environment as well as within the stock market tracking.^16,17 This, as well as the illusion of control distortion, allows gamblers to feel in control of their addiction psychologically, while neurochemical reactions work in tandem in order to reinforce the addictive behavior.¹⁵ When understanding the neurobehavioral and neurochemical components of gambling and risk-taking behaviors, one area of the brain and one chemical are the most prominently featured: the prefrontal cortex (and specifically its connectivity with the striatum) and dopamine.

Specifically, within pathological gamblers, greater dopamine releases were found within the dorsal striatum, with the amount of dopamine release being correlated with both levels of excitement and gambling severity.¹⁵ Dopamine, when used as a natural “reward,” targets a system within the brain referred to as the reward system, which includes the prefrontal cortex, dopaminergic midbrain, ventral striatum (which is most prominent in the outcome of reward-based decisions), amygdala, and insula.⁸ This system works in tandem to code associations of high emotional experiences – such as winning a bet or gambling – with physiological responses.⁸ By doing this, the brain then uses the physiological effects of high-intensity risk-taking as both reward and motivation, further perpetuating this behavior, a large reason pathological gamblers are compared to those with substance abuse disorders. The insula plays a large role in processing not just the physiological stimuli associated with gambling and risk-taking behavior but also the processing of the emotional high results of partaking in it.⁸

The purpose of this study was to gain a greater understanding of how interoception is affected with those who have substance-based alcohol addiction while also discriminating between patient populations (those who sought inpatient treatment and those who did not), and furthering research of non-substance-based addiction of gambling disorder (GD) and its effects on interoception. By comparing GD individuals with AUD individuals, we also gain a greater understanding of the differences in functioning in substance-based versus behavior-based addictions. Albeit neural underpinnings of interoception and basic clinical implications across patients with addiction disorders are to be revealed, little is known about how their subjective evaluation of interoceptive awareness of these patients among the Japanese population and whether psychological interoceptive awareness would differ between sub-categories of alcohol and gambling. Preliminary assumptions made were that those with alcohol addictions would have lower interoceptive abilities than those with gambling addictions and that both addicted populations would have lower interoceptive abilities in comparison to the control group.

METHODS

Participants

This study consisted of three groups: healthy control (C), patients with alcohol use disorder (AUD), and patients with gambling disorder (GD). The control sample (n = 809) was acquired from a previous study (Kobayashi et al., 2021).¹⁸ Alcohol use disorder (n = 50) and gambling disorder (n = 41) samples were diagnosed according to the fifth edition of the DSM (DSM-5) and recruited at two clinics at the Senogawa Hospital and the Yokogawa Ekimae Clinic in Hiroshima, Japan. As for the patient group, data were collected at the time of admittance to their hospital prior to clinical examination. As for the control group, data were collected online instead of offline at the clinics or hospitals due to an apparent reason for difficulty recruiting healthy volunteers at clinics or the hospital. As described below, the self-report healthy control participants did not complete either SOGS or AUDIT screening (see Table 1).

TABLE 1 Descriptive summary of groups on number of samples (N), followed by age, AUDIT score, SOGS score, and BPQ scores (M ± SD followed by range [minimum to maximum]) for each measure.

	Control	AUD	GD
Overall	Inpatient	Outpatient
N (females: males)	809 (406: 403)	50 (10: 40)	24 (3: 21)	26 (7: 19)	41 (3: 38)
Age	38.38 ± 9.80 (18–70)	53.20 ± 12.42 (27–76)	55.67 ± 12.52 (30–76)	50.92 ± 12.13 (27–72)	36.68 ± 9.98 (20–58)
AUDIT	n/a	25.06 ± 7.25 (11–40)	26.46 ± 6.27 (14–36)	23.77 ± 7.96 (11–40)	n/a
SOGS	n/a	n/a	n/a	n/a	11.41 ± 2.40 (7–18)
BPQ-BAVSF-J	27.28 ± 8.07 (12–60)	21.84 ± 6.69 (12–39)	22.79 ± 6.83 (12–39)	20.96 ± 6.57 (13–37)	20.39 ± 5.41 (12–35)

Additionally, the AUD sample was further subsequently differentiated into subgroups of treatment status – inpatient treatment (n = 24) and outpatient treatment (n = 26). The treatment status was determined on the visit to one of the clinics after administering the questionnaire. Of the inpatient AUD group, 11 cases at the Senogawa Hospital had been out-patient and then diagnosed as inpatients whose questionnaires were acquired on the day of hospitalization. All patients agreed and signed a consent form approved by a local ethical committee (the Senogawa Medical Corporation Ethical Committee). See Table 1 for a descriptive summary.

Measures

Assessment of interoceptive sensitivity

The BPQ was originally developed in English by Porges.¹⁹ The BPQ-VSF is a very short version of the BPQ's Body Awareness subscale, consisting of 12 items measuring sensitivity to internal bodily sensations and functions (dry mouth, breathing, swelling, muscle tension, goosebumps, gastrointestinal pain, stomach distension, tremor in lips, feeling of skin inversion, feeling of spitting, swallowing, and heartbeat). It is a 5-Likert scale from “Never” to “Always.” All participants completed the Japanese version of the Body Perception Questionnaire Body Awareness Very Short Form (BPQ-BAVSF-J; Kobayashi et al., 2021).¹⁸ Scores range from 12 to 60, with higher values indicating hypersensitivity and lower values indicating hyposensitivity. For the sake of simplicity, we refer to the BPQ-BAVSF-J score as the “BPQ score” in this manuscript.

BPQ scores in the control group (816 samples: 406 females, 403 males, and 7 not-reported cases) were acquired from Kobayashi et al. (2021).¹⁸ For the sake of gender matching purposes, 7 cases were rejected for subsequent analyses. A total of 809 cases were included as the control group in this study. See Appendix S1 and S2 for cumulative percentile in the Japanese population compared against US samples (retrieved from the BPQ Manual).

To note, sex differences on the BPQ score were not considered for the subsequent analysis because the effect of sex differences within the control samples (females: 27.9 ± 7.77; males: 26.57 ± 8.31) was significant yet considerably negligible with a very small effect (F(1,807) = 6.119; p = 0.014; η_p² = 0.008).

Assessment of gambling behavior

In addition to the BPQ, gambling disorder patients completed the Japanese version of the South Oaks Gambling Screen (SOGS; Kido & Shimazaki, 2007).²⁰ The SOGS consists of 20 items measuring gambling history, frequency, and experience of gambling-related impacts on one's life. Scores range from 0 to 20, with a score of 5 or more indicating a high likelihood of gambling disorder.²¹ Neither the AUD nor control groups completed the SOGS as a part of screening procedures.

Assessment of alcohol misuse

In addition to the BPQ, alcohol use disorder patients completed the Japanese version of self-report Alcohol Use Disorders Identification Test (AUDIT²²). The AUDIT is a screening tool consisting of 10 items measuring the severity of alcohol consumption, dependence, and experience of alcohol-related harm. Scores range from 0 to 40, with higher scores indicating greater alcohol misuse severity. Neither the GD nor control groups completed the AUDIT as a part of screening procedures.

Data analysis

We performed an analysis of covariance to analyze differences in BPQ scores between the control, alcohol misuse, and gambling disorder groups. The BPQ values were not normally distributed across the groups (Kolmogorov–Smirnov tests corrected by Lilliefors were significant <0.001 for control, <0.05 for GD but not significant for AUD 0.20). A bivariate Spearman correlation revealed a weak yet significant correlation between Age and BPQ score in the Control sample (Spearman's ρ₈₀₉ = − 0.207, p < 0.001). Figure 1A shows the BPQ scores as a function of age. In addition, the effect of sex differences within the control samples was also weak yet significant such that females (27.9 ± 7.77) had slightly higher BPQ scores than males (26.57 ± 8.31) with a small effect (Mann–Whitney U test: Z = 2.845; p = 0.004; Cohen's d = 0.17; Figure 1B). Therefore, age and sex were used as a covariate of no interest (a.k.a., “nuisance variable”) for the subsequent analyses. A nonparametric (Quade's) ANCOVA was conducted to determine statistical differences in BPQ scores across the groups while controlling for sex and age.²³ The IBM SPSS Statistics Version 28.0.1.1 was used for all the analyses. Table S1 provides quartile criteria for the BPQ based on the data retrieved from Kobayashi et al. (2021).¹⁸

[IMAGE OMITTED. SEE PDF]

RESULTS

The summary of descriptive statistics is shown in Table 1.

Comparison within AUD group

There were also no differences in BPQ scores between first-visit patients (AUD-I-1st and AUD-O-1st) and re-examined (AUD-I-Re) patients (F(1,48) = 0.014; p = 0.907, n.s.). Compared all three sub-groups, there were no differences among the three AUD patient sub-groups who were subsequently diagnosed for hospitalization regardless of first visit (“AUD-I-1^st”) or not (“AUD-I-Re”), and diagnosed as outpatient (“AUD-O-1^st”) groups (F(2,47) = 0.856; p = 0.431, n.s., not significant). There were no significant differences between the two inpatient sub-groups (“AUD-I-1^st” and “AUD-I-Re”: F(1,35) = 0.044; p = 0.835, n.s.). Given these results, we included all AUD samples for the following analyses unless specified otherwise.

Comparison across control, gambling addiction, and alcohol addiction groups

The mean and SD of the BPQ scores on all groups (namely, Control, AUD, and GD groups) are summarized in Table 1. See Table 2 for the summary of the results of this ANCOVA. See Figure 2A–C for AUD v.s. Control, GD v.s. Control, and AUD v.s. GD, respectively. The Quade's ANCOVA comparing mean BPQ score controlling for age and sex as covariates revealed a significant effect of group factor on BPQ score (F(2,897) = 18.093; p < 0.001). Individual pairwise comparisons revealed that the BPQ score of the control group was significantly higher than that of the GD group with a large effect (t = 5.410, p < 0.001, d = 0.87; Figure 2B), as well as that of the AUD group with a small to medium effect (t = 2.912, p = 0.004, d = 0.42; Figure 2A). Notably, BPQ score of the GD group was significantly lower than that of the AUD group with a small to medium effect (t = −2.097, p < 0.001, d = 0.87; Figure 2C).

TABLE 2 Quade's ANCOVA comparing control, gambling disorder, and alcohol use disorder groups, controlling for age and sex.

Comparisons	t	p	d
Control	AUD	5.410	<0.001	0.87
Control	GD	2.912	0.004	0.42
AUD	GD	2.097	0.036	0.44

[IMAGE OMITTED. SEE PDF]

Comparison across all groups splitting the AUD samples into in- and out-patients

Another ANCOVA controlling for age and sex was conducted, this time with the AUD group further split into inpatient and outpatient groups: Control, Gambling Addiction (GD), Alcohol Addiction Inpatient (AUD-I), and Alcohol Addiction Outpatient (AUD-O). This Quade's ANCOVA comparing mean BPQ score controlling for age and sex as covariates revealed a significant effect of group factor on BPQ score (F(3,896) = 12.511; p < 0.001). Results indicated that Control BPQ scores were significantly higher than that of the AUD-O group with a medium to large effect (t = 2.918, p = 0.004, d = 0.58). It was also indicated that the BPQ scores of the GD group were significantly lower than that of the AUD-I group with a medium to large effect (t = −2.380, p = 0.018, d = 0.61). There were no significant differences in BPQ score between the AUD-O and AUD-I groups (Z = −1.146, p = 0.252) even after controlling for age and sex (t = 1.155, p = 0.249, d = 0.33). All other comparisons remained nonsignificant (see Table 3 for a summary of the results of this ANCOVA).

TABLE 3 Quade's ANCOVA comparing control, gambling disorder, alcohol use disorder inpatient, and alcohol use disorder outpatient groups, controlling for age and sex.

Comparisons	t	p	d
Control	GD	5.411	<0.001	0.87
Control	AUD-I	1.229	0.219	0.25
Control	AUD-O	2.918	0.004	0.58
GD	AUD-I	−2.38	0.018	0.61
GD	AUD-O	−1.137	0.256	0.29
AUD-I	AUD-O	1.155	0.249	0.33

DISCUSSION

Awareness of our bodily signals is pivotal to our daily life, and accumulating research suggests clinical relation to mental disorders. Of many mental disorders, addiction is thought to be associated with insensitivity to their target substance or addictive behavior. In this study, we assessed subjective ratings on body awareness using the BPQ-BAVSF-J (BPQ) as a measure of interoceptive sensibilities among two different types of addictive disorder population groups (AUD and GD) in order to gain a greater understanding of how alcohol addiction and gambling disorder relates to addictive behaviors and metacognition of their interoception. The two patient groups were compared against a healthy control population.

Body awareness in addiction samples

As previously predicted, BPQ scores were found to be lower within the addicted populations as compared to the scores of their healthy counterparts. With the highest BPQ-BAVSF-J scores belonging to the C group, both AUD and GD groups had lower BPQ scores than the C group. Interoceptive sensibilities may be affected within addicted populations due to damage to the insular cortex,¹¹ which leads to increased impulsivity, damage to emotional regulatory processes, inability to accurately perceive and track physical sensations, etc.² (Clark & Murch, 2016).

Body awareness in gambling disorder

Within the addiction group, those in the GD sub-group had lower BPQ scores than those within the AUD subgroup. Gambling disorder highlights key neurobiological effects of addiction solely through maladaptive behavioral processes, with the absence of substance-driven urges.²⁴ Frontostriatal function is hypothesized to have a primary role in action selection or reinforcement learning.¹⁵ A study performed on primates found that the lateral prefrontal cortex (LPFC; caudal area 46) had a large portion of neurons involved in selected actions and also had equal involvement in reinforcement actions when being compared to the dorsal striatum (primarily the anterior caudate nucleus).²⁵ Dopamine, similarly involved in substance abuse disorders and reward-driven behaviors, is frequently investigated in line with reward-driven motivation with gambling and with the physiological and psychological effects of dopamine release itself.¹⁵ In combination with higher levels of noradrenaline and lower levels of serotonin,²⁴ this leads to a chronic lack of impulse control, which progressively deteriorates throughout a number of stages over the course of the disorder.²⁶

Body awareness in AUD

It has been reported that AUD individuals with high interoceptive sensitivity may have problems controlling their behaviors while experiencing negative emotional states.⁹ Additionally, those with AUD have deficits in facial emotional recognition, specifically surrounding incorrectly attributing anger and disgust.^14,27 It may further implicate the incorrect attribution of interoceptive processes and the psychosocial functioning of those with AUD, leading to aggressive behavior.¹⁴ Within the brain itself, individuals with AUD were found to have a variety of different changes in various areas, including smaller insular cortices, greater white matter within the insula, enlarged amygdala volume, and reduced insular gray matter in adolescent groups.^28-30 These changes correlated with marked increases in impulsivity, compulsivity, decreased BOLD signaling in some cases (while performing visual attention and cognitive control tasks), and increases in BOLD signaling in others, depending on the level of consumption.³¹

Differences between gambling versus alcohol addiction

The AUD population's BPQ score-BAVSF-J was significantly higher than their GD counterparts (both within and outside the fixed-age range set), indicating a key difference in interoceptive processes despite the two disorders' similarities and comorbid tendencies. Though AUD is based on substance consumption and gambling disorder is based on action-oriented behavior, both disorders share similarities in their diagnostic criteria and general nature due to both addictions inciting maladaptive and dependent behaviors.²⁶ As well as their criterion similarities, these two disorders are highly comorbid among certain populations; GD individuals were found to be at increased risk for AUD, and AUD individuals were at increased risk for GD.³² However, levels of severity are defined and categorized differently within the diagnosis of these disorders, with substance abuse disorders having two levels of severity (substance dependence and substance abuse) while gambling disorder only has one (gambling disorder).²⁶ Additionally, gambling disorder is primarily cognition-based, making cognition therapy and impulse control training the primary treatment styles as opposed to substance abuse, which must factor in substance consumption and the physiological effects of abstinence or gradual reduction of substances.²⁶ This begs the question of differences in addictive effects on those driven solely by behavior (such as GD populations) and those driven by substance. The AUD groups (particularly the AUD-I subgroup) were significantly higher than the GD population. It may highlight a link between interoceptive sensibility and addictive disorders due to damage within the insular cortex so that AUD individuals are dependent on a substance (alcohol in this case), while GD who are behaviorally or mentally dependent^5,11 (Jakubczyk et al., 2019).⁹ This critical trend may highlight potential functional differences between the reward systems within addictive disorder. Nevertheless, future neurophysiological assessment studies would be needed to validate the neuroanatomical underpinnings of substance-based and non-substance-based addiction.

Differences in AUD in-patient and out-patient

Another question of interest was to examine if BPQ can be a supportive diagnosis tool for the AUD population. It could be assumed that metacognitive awareness for their physiological signals may be severely impaired in inpatient participants with severe cases of AUD requiring hospitalization than in outpatients. The BPQ revealed differences in severity that the AUDIT score was insufficient in representing independently. However, the reason as to why the BPQ score of the AUD-I group – the group with a more severe case of AUD – was closer to that of the control than the AUD-O group remains unknown. While this is a topic for future research, the unexpected result may be explained by the fact that the AUD-I group was further split into patients with no previous hospitalization history and those who did. On average, the AUD-I patients with a previous history of hospitalization had an average BPQ score that was higher than that of AUD-I patients who were hospitalized for the first time, and the average BPQ of AUD-O and first-time AUD-I groups were very similar. It was not clear from this study if the BPQ score can be a diagnostic tool for AUD; however, future studies could trace the changes in the BPQ scores and associated physiological markers. Regardless, this study supported impaired interoceptive awareness among addictive patients against control, the scoring reference of BPQ (Appendix S1 and S2) may be of help in clinical settings.

Limitations

There were certain limitations in this study. First, it was a relatively small sample size for both AUD and GD populations compared to the healthy control. Second, gender differences could not be thoroughly considered due to the lack of female participants, particularly among AUD. Third, adolescents, a group primarily susceptible to addiction and with some of the greatest effects of addiction,^24,28,29,30 were not included as participants in the study. Fourth, the BPQ questionnaire measures interoception, as opposed to any other given questionnaire that may relate to interoceptive sensibility and possibly measures it better within certain dimensions of interoceptive abilities. Fifth, those within the AUD-I samples reported the BPQ when entering their inpatient treatment, putatively at the highest risk of their addictive symptoms. A follow-up of their BPQ score during or at the end of treatment would be necessary to examine the causal relation between metacognitive body awareness and addictive symptoms. Because AUD and GD are highly comorbid among populations within the United States and Canada,³² further research may be valuable in determining the correlation between these two disorders within Japanese populations, as well as comorbidity's effects on interoception in comparison to the presence of just one disorder. Additionally, while we observed a large effect of significant differences between the control and those patient groups, we lacked appropriate screening among the controls and AUD for gambling (SOGS) and controls and GD for alcohol misuse (AUDIT). One could re-examine the findings with appropriate screening procedures for completeness.

CONCLUSIONS

In this study, we assessed using the BPQ questionnaire based on a subjective assessment of their body awareness. There are several neurophysiological markers for interoception, such as heartbeat-evoked potentials³³ or neural responses for inhibitory control and error processing.³⁴ Further neurophysiological investigation and validation may be required for further understanding of neural underpinnings on interoceptive awareness in addiction. As mental illness is also highly associated with autonomic functions, in addition to the body awareness examined in this study, a short form of BPQ³⁵ that includes autonomic subscales may benefit clinical uses. As highlighted in this study, evaluation of interoceptive awareness among addictive disorders may become a usual easy-to-use tool in clinical settings and improvement of interoceptive awareness such as mindfulness or meditation^36,37 may lead to fundamental treatment for alcohol or gambling addiction disorders. The hanging fruit has been picked; the future of neuropsychological and neurophysiological assessment would uncover the complexity of these addictive disorders.

AUTHOR CONTRIBUTIONS

Giselle London: Drafting (Introduction and Conclusion), Interpretation; Hiroko Hida: Analysis (patient data), Drafting (Methods and Results), Interpretation; Ariyuki Kagaya: Conception, Supervision of Acquisition, Reviewing; Shigeto Yamawaki: Conception, Reviewing; and Maro G. Machizawa: Conception, Analysis (control data), Supervision of Analysis, Interpretation, Drafting, Reviewing.

ACKNOWLEDGMENTS

We thank Dr Ryota Kobayashi and Dr Tatsuru Honda for supplying the original data for the control group (Kobayashi et al., 2021). We also thank Ms Chika Shimohara, Dr Atsushi Shimohara, and Dr Ryotaro Tsukue for their helpful discussion.

FUNDING INFORMATION

No funding was received for conducting this study.

CONFLICT OF INTEREST STATEMENT

Author MGM also has a leadership role and owns stock of Xiberlinc Inc. Author AK has received research grants from a Health Labour Sciences Research Grant (20GC1015) and is one of the directors of the “The Japanese Society of Alcohol-Related Problems.” Author SY received consultant honoraria from Xiberlinc Inc (from April 2022 to March 2023). Authors GL, HH, and AK declare that they have no financial interests.

DATA AVAILABILITY STATEMENT

The data that support the critical findings of patients' responses are attached as Appendix S1 and S2. Please see Appendix S1 and S2 for descriptive statistics as well as the variability of the control population's BPS-BAVSF-J scores that may be relevant for clinical usage.

ETHICS STATEMENT

Approval of the Research Protocol by an Institutional Reviewer Board: This study was approved by the Senogawa Medical Corporation Ethical Committee, Approval Nos. R03-04 & R03-05-1.

Informed Consent: All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2000 (5). All informed consent was obtained from all patients to be included in the study.

Registry and the Registration No. of the study/trial: N/A.

Animal Studies: N/A.

PERMISSION TO REPRODUCE MATERIAL FROM OTHER SOURCES

We obtained permission from the original co-author of Kobayashi et al. (2021).¹⁸

References

Chen WG, Schloesser D, Arensdorf AM, Simmons JM, Cui C, Valentino R, et al. The emerging science of Interoception: sensing, integrating, interpreting, and regulating signals within the self. Trends Neurosci. 2021;44(1):3–16. [DOI: https://dx.doi.org/10.1016/j.tins.2020.10.007]

Fissler M, Winnebeck E, Schroeter T, Gummersbach M, Huntenburg JM, Gaertner M, et al. An investigation of the effects of brief mindfulness training on self‐reported interoceptive awareness, the ability to decenter, and their role in the reduction of depressive symptoms. Mind. 2016;7:1170–1181.

Hanley AW, Mehling WE, Garland EL. Holding the body in mind: interoceptive awareness, dispositional mindfulness and psychological well‐being. J Psychosom Res. 2017;99:13–20.