Online gaming has become a staple of our daily lives, serving as a popular form of entertainment. However, excessive gaming can lead to impairment in academic performance, work responsibilities, and both physical and mental well-being. In 2013, Internet Gaming Disorder (IGD) was included in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), as a condition that requires further evaluation [1]. The DSM-5 recommended nine tentative diagnosis criteria for IGD, including: 1) preoccupation, 2) withdrawal, 3) tolerance, 4) loss of control, 5) give up other activities, 6) persistence, 7) deception, 8) escape, and 9) negative outcomes. A diagnosis of IGD requires the endorsement of at least five of these nine criteria.

The DSM-5 criteria have been widely adopted in research and clinical practices [2-4]. Many instruments have been developed based on these criteria. For example, the Ten-Item Internet Gaming Disorder Test (IGDT-10) [5], the 9-item Internet Gaming Disorder Scale Short-Form (IGDS9-SF) [6], the Internet Gaming Disorder Scale (IGDS) [7], 7-item Game Addiction Scale (GAS) [8], and the Chinese IGD Scale (C-IGDS) [9]. The DSM-5 standard is currently the most influential diagnostic standard for IGD, which has undoubtedly greatly promoted research in IGD-related fields.

However, the DSM-5 criteria have also faced considerable criticism. Firstly, the diagnostic criteria for IGD were mainly drawn from those of gambling and substance use disorder [10]. Yet, the theoretical rationality of this approach has been questioned by some researchers. For instance, Pies [11] claims that some well-established features of substance use disorders, such as withdrawal and tolerance, can be difficult to define in the context of IGD as it does not involve chemical consumption. Likewise, some criticisms suggest that give up other activities lacks a clear connection to functional impairment and can also be a symptom of depression (which is highly comorbid with IGD) [12]. Secondly, empirical studies have demonstrated low diagnostic accuracy for certain criteria for IGD. Research by Ko et al. [13] highlighted concerns about the reliability of deception and escape, while other studies, including those by Ko et al. [14] and Lemmens et al. [7], have noted similar issues with the escape criterion. These findings suggest that the current diagnostic criteria may not effectively capture the complexities of gaming behaviours, raising questions about the overall validity of these criteria in diagnosing IGD.

Item response theory (IRT) is a commonly adopted psychometric model that aims to determine the relationship between latent traits (e.g., IGD severity) and responses [15]. IRT enables precise measurement of difficulty, discrimination, and item information of each item, and allows direct comparison of these features between items [16]. IRT has been frequently adopted in studies of IGD [5,17-19]. For example, Király et al. [5] carried out an IRT analysis on the IGDT-10 and found that IGD manifests through a different set of symptoms depending on the severity level. Specifically, persistence, preoccupation, negative outcomes, and escape were associated with lower severity of IGD, while tolerance, loss of control, give up other activities, and deception were associated with more severe levels. They also found that preoccupation and escape provided very little information to estimate IGD severity, related to other criteria. Likewise, Gomez et al. [17] applied the IRT to the items of IGDS9-SF and found that escape had a relatively lower discrimination compared to the other eight criteria. It also showed low reliability at all trait levels. However, these studies were all conducted with a single scale, and the conclusions are limited to the given scale rather than the diagnostic criteria themselves. As a result, it remains unclear whether these findings, for example, the low discrimination in escape, were due to the definition of symptoms per se or the wording of the scales.

The study aimed to examine the psychometric properties of the nine DSM-5 criteria of IGD by conducting IRT analyses on four commonly used DSM-5-based self-report scales: GAS, IGDT-10, IGDS9-SF, and IGDS. Based on previous studies, we hypothesize that escape may have lower IRT parameters (discrimination, difficulty, and item information) compared to other diagnostic criteria.

The present study aimed to examine the psychometric properties of the nine criteria of IGD through IRT analyses of DSM-5-based scales. All nine DSM-5 criteria demonstrated high discrimination, providing substantial item information for diagnosing IGD. The used scales, despite varying in wording and scoring methods, exhibited strong correlations in total scores (r≥0.502, p<0.001) and high consistency (Kendall’s W ≥0.656, p<0.05) concerning the fitted IRT parameters. Among the nine criteria, escape showed the lowest cross-scale discrimination, item information, and difficulty. In contrast, withdrawal showed the highest item information and discrimination, and the second highest difficulty. Additionally, there was no evidence of DIF related to sex or age (adolescents vs. adults) across nearly all scale items. Refers to the accuracy of the criterion in different latent traits [27].

All item discrimination values exceeded 1.35 (1.38-3.72), indicating very high to perfect discrimination according to Baker’s standard [16]. This finding indicates that all nine criteria, despite variation in difficulty and item information, can correctly distinguish respondents with and without IGD [5,17]. Moreover, our DIF analyses suggest that these criteria can be applied fairly in different sex and age groups. Together, our results seem to support validating the nine DSM-5 criteria of IGD.

Importantly, we found that despite variations in wording and scoring methods, these scales exhibited high consistency in the fitted IRT parameters (Kendall’s W ≥0.656). These results seem to indicate that each diagnostic criterion could possess a certain degree of tolerance. In other words, what is measured does not have to align precisely with the core pathological changes described by the symptoms, but rather with related variations. This consistency among scales also suggests that, at least for these nine symptoms, their relative importance, in relation to the “core” pathological changes of IGD, may be essentially stable. For instance, the distance of escape from the “core” of IGD could be greater than that of withdrawal. This may be more intuitively illustrated through network analysis [40]. Moreover, all four scales met the unidimensionality assumption, which not only indicates suitability for IRT analysis but also suggests that IGD likely has only one “core” pathological change. This conclusion is consistent with existing research on individual scales [5,8,17,25]. Therefore, our results seem to indicate that IGD has a singular core pathological change, encompassing the aspects described by the nine symptoms, and the relative importance of these symptoms according to the core pathological change is likely stable across scales.

The escape criterion exhibited the lowest discrimination, difficulty, and item information among all nine diagnostic criteria for IGD. These results align with multiple previous IRT studies, which found that escape was less effective than other criteria in distinguishing between individuals with IGD and those who are healthy [5,17,41]. Our results expanded these findings by demonstrating that the escape performs poorly across different scales with varying wording and scoring methods, i.e., IGDS9-SF, IGDT-10, IGDS, and GAS, suggesting a cross-scale generalization of this finding. Indeed, studies using different instruments or methods have also reported low diagnosis accuracy of the escape criterion. For example, Ko et al. [13] evaluated the diagnostic validity of the nine DSM-5 criteria and the criteria of craving and irritability based on the Diagnostic Criteria of Internet Addiction for College Students, and found that, except for the deception and escape criteria, all DSM-5 criteria had diagnostic accuracy. This finding was reiterated in a study conducted in 2020 [14]. Likewise, in a Delphi study, 29 international experts on IGD rated the escape and tolerance as inadequate to distinguish problematic from normal gaming [42]. Additionally, a factorial analysis on data based on the Compulsive Internet Use Scale indicated that the item on escape had no association with the other items [43], a finding echoed in a recent IGDS factor analysis [44]. Together with these findings, our results suggest that the underperformance of escape in IRT is likely to be due to the definition of this criterion itself, rather than to differences in the wording of different questionnaires. The escape could be controversial for several reasons. Firstly, escape is one of the main motivations of game-playing in general gamers, but not just addicted ones [41,45]. A systematic review suggested that escapism and avoidance coping represent both a motivational factor mostly associated with disordered gaming [46]. Secondly, IGD is often co-morbid with depression [47], and escapism may also occur under a depressed mood. Existing studies have demonstrated that depressed mood may be a mediator between IGD and other psychological factors, such as mood control [48] and causality orientations [49]. Kim et al. [50] found that escape was the only significant item associated with depression among symptoms of IGD, and underscored this connection. However, it should be stressed that the escape criterion demonstrated acceptable levels of discrimination, difficulty, and item information in diagnosing IGD, suggesting its relevance to addiction-related pathological changes. In line with this perspective, mood modification (including “high” and “escape”) was considered one of the core components of addiction [51]. In summary, although the escape criterion met the minimum statistical threshold for acceptability on some metrics, its consistently inferior performance relative to all other criteria across four different instruments raises significant concerns about its utility and validity.

Contrary to escape, withdrawal showed the highest discrimination and item information, and the second highest difficulty among the nine criteria. These results were similar to several previous IRT studies, highlighting the significant role of withdrawal in diagnosing IGD [19,41]. Indeed, multiple studies have demonstrated that withdrawal is a core presentation in IGD [52,53]. A recent network analysis of IGD symptoms suggested that withdrawal, together with loss of control, persistence, and tolerance, may form the core of the network [40]. Our results align with these studies, suggesting that withdrawal could reflect the core pathology of IGD, which can provide more information, better discrimination, and, with high reliability, distinguish between IGD and healthy individuals. Withdrawal may be central to addiction for two reasons: 1) Withdrawal is a diagnostic symptom in all existing addictive disorders, including substance use disorder, gambling disorder, and IGD [1], highlighting its commonality in addiction. 2) The significance of withdrawal is emphasized in the negative reinforcement theory of addiction [54], which suggests that negative reinforcement driven by withdrawal symptoms plays a crucial role in the development and maintenance of addiction. While some debate whether withdrawal exclusively drives addiction [55], few studies dispute its importance. Thus, withdrawal may represent a core symptom of IGD. Importantly, the significant role of withdrawal in IGD contributes to ongoing discussions about the relevance of substance-use criteria in behavioural addictions [11], suggesting that chemical consumption—and related physical discomfort—might not be central to withdrawal symptoms. The typical withdrawal symptoms in IGD are irritability, restlessness, boredom, anhedonia, and gaming craving [52,56]; physical withdrawal symptoms are rarely reported [57]. However, this does not mean that IGD can be easily quiet. In fact, the irritability, anxiety, and boredom resulting from forced abstinence are precisely the reasons many individuals with IGD seek treatment. Most participants (84%) of IGD indicated that they had to play games because of these withdrawal symptoms [52]. However, despite its widespread recognition, there is a lack of qualitative studies providing detailed clinical descriptions of this symptom.56 Further studies with more specific qualitative descriptions, maybe with more objective measurements such as heart rate, neuroimaging techniques, are warranted [52].

In addition to withdrawal, tolerance and loss of control also showed high item information and discrimination. In line with our results, an IRT study of IGDS-SF, where withdrawal, tolerance, and persistence, along with preoccupation, were identified as the strongest discrimination items [41]. Our results also align with the findings of Gomez et al. [40], which suggested that withdrawal, persistence, tolerance, and loss of control form the core of the network of IGD symptoms. In sum, our results indicate that withdrawal, tolerance, and loss of control could play a significant role in distinguishing between individuals with IGD and those who are healthy.

This study has some limitations. First, our sample covered a small age interval of 11-30 years old, given that most IGD occurs during adolescence and early adulthood. This sample does not allow for generalization to another age interval, such as the middle-aged. Secondly, our data were derived from self-report scales, while DSM-5 diagnoses are typically administered through clinical interviews. Future studies directly assessing the DSM-5 criteria using data from clinical interviews or evaluation scales (e.g., the Chinese IGD scale) may provide more information on the diagnostic efficacy of these criteria. Thirdly, to facilitate cross-scale comparisons of IRT parameters, we combined items 9 and 10 of the IGDT-10 by taking the maximum score of these two items. Additional IRT analyses with items 9 and 10 combined and treated separately demonstrated good fit for both methods (Supplementary Tables 3 and 4). Furthermore, the combined item exhibited comparable discrimination and item information, but slightly lower difficulty (ranges of b value changed from 0.659-2.685 to 0.554-2.010) (Supplementary Table 5). This combination could make the criterion of negative outcome easier to endorse in the IGDT-10.