Introduction

Gaming is one of the most popular recreational activities worldwide. However, excessive gaming may impair daily life functions among vulnerable gamers [1•]. Because mounting empirical studies demonstrated that IGD causes clinically significant harm, internet gaming disorder is proposed and listed in the “Conditions for Further Study” chapter of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) [2, 3]. The inclusion of IGD in DSM-5 [4] sparked debate about its positive and potential adverse effects on diagnosed individuals [5]. It contributes to promoting research and enabling the provision of treatment to patients with IGD [3]. However, scholars raise the concern that it might stigmatize the patient or over-pathologize healthy gamers [5]. The longitudinal complication, the prevalence in regions over the world, clinical treatment demands, and public mental health impact have driven the need to have practical criteria to make a reliable diagnosis for treatment and prevention [6]. Subsequently, the International Classification of Diseases, 11th Revision (ICD-11) has included gaming disorder (GD) as an official diagnosis in the section entitled “Disorders due to substance use or addictive behaviours” [7]. However, the IGD and GD criteria differ between these two diagnostic systems. Accordingly, this narrative review focuses on the difference between the two diagnostic systems and compares the DSM-5 criteria for IGD (DSM-5-IGD) and ICD-11 criteria for GD (ICD-11-GD).

DSM-5 Criteria for IGD

The DSM system provides reliable diagnostic criteria for mental disorders for facilitating patient care and scientific research [8]. It emphasizes distinguishing between psychopathology and normality and providing criteria to define the disorder [10]. DSM-5 also states that psychiatric disorders, including clinically significant distress or disability, reflect an underlying psychological dysfunction. These features are not merely an expected response to common stressors or a result of social deviance. Criteria for psychiatric disorders should demonstrate evidence-based validity and clinical utility [8]. The DSM-5 Substance Use Disorder Work Group reviewed over 250 publications for IGD and reported that the validators, such as prevalence, course, treatment, and biomarkers, were inconclusive and that the clinical utility, such as the natural course, comorbidities, and intervention, was limited in evidence-based data. They recruited the IGD criteria in section III, but not an official diagnosis, of DSM-5 to provide a definite feature to foster research in internet gaming disorder, such as prevalence or cross-culture comparison [10, 11].

In DSM-5, IGD is defined as persistent and recurrent gaming that leads to significant impairment or distress. Five or more of the following criteria should be met within 12 months before individuals can be diagnosed with IGD: preoccupation with gaming, withdrawal, tolerance, unsuccessful attempts to control, psychosocial problems, deceiving, escape, and impairment of function. Two diagnostic studies on adults [12] and adolescents [13] have supported the validity of the DSM-5 criteria for IGD. However, one of the studies reported lower diagnostic accuracy for deception and escapism [12]. Castro-Calvo et al. demonstrated an agreement among experts that tolerance and escape have lower value in diagnostic validity and clinical utility [14••]. Valid and reliable screen tools have been developed for evaluating each of the nine DSM-5 criteria for IGD; examples of these tools are the 10-item Internet Gaming Disorder Test (IGDT-10) [15] and the Internet Gaming Disorder Scale–Short Form (IGDS-SF) [16]. These tools may assist medical experts in identifying individuals with harmful gaming habits. Since the gaming-caused functional impairment is difficult to be evaluated in the self-report questionnaire, a diagnostic interview is required to confirm the diagnosis among screen-positive people.

ICD-11 Criteria for Substance Use Disorder or Addictive Behavior

Unlike DSM-5, public health utility is the highest priority of ICD-11 to contribute to clinical applications, research, teaching and training, health statistics, and public health [17]. Thus, ICD-11 represents addictive behavior on a spectrum in various levels and patterns to enable clinical experts to recognize symptoms early and target prevention [18]. Thus, the ICD-11 coding reflects the severity and stages of substance use disorder [18], such as hazardous alcohol use, episodic harmful alcohol use, harmful patterns of alcohol use, and alcohol dependency [19]. The spectrum approach can reduce the treatment gap for individuals who benefit from early intervention [18].

Comparing Approaches and Characteristics of DSM-5 Criteria for IGD and ICD-11 Criteria for GD and Hazardous Gaming (Table 1 and Fig. 1)

Table 1 Comparison of approaches and characteristics of DSM-5 criteria for IGD and ICD-11 criteria for GD
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Fig. 1
figure 1

The difference in approach between the International Classification of Diseases, 11th Revision (ICD-11) criteria for gaming disorder (GD) and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for internet gaming disorder (IGD). Footnote: HG, hazardous gaming

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Similar to the criteria for other addictive behaviors, ICD-11 provides a set of criteria for identifying GD and hazardous gaming. The ICD-11 criteria can assist clinical professionals in treating patients with severe dependency problems and preventing further development during the early stages of GD [7]. GD is defined as a pattern of gaming behavior where the individual exhibits (1) impaired control over gaming; (2) increasing priority given to gaming behavior; and (3) gaming despite negative consequences. These behavioral patterns are required to result in significant distress or functional impairment over an extended period (e.g., 12 months).

Similar to the features of gambling disorder, the physiological features of substance dependency or IGD, such as withdrawal and tolerance, are not included in the criteria for GD. Because gaming does not produce a pharmacological effect, determining tolerance based on dosage or withdrawal symptoms based on half-life is impossible. Further, experts agree that tolerance has a lower diagnostic validity, clinical utility, and prognostic value [14••]. Withdrawal symptoms have been reported to be experienced predominantly through affective or urge symptoms rather than a physiological response [20, 21]. A prospective evaluation revealed that the only reported physiological symptom of GD is a mildly increased heart rate [21].

Withdrawal symptoms vary considerably, including affective, anhedonia, and gaming urge symptoms [21]. Furthermore, they decline rapidly in the first 24 h after abstinence from gaming [20, 21]. Moreover, cognitive and motivational mechanisms affect how tolerance relates to gaming time [22]. The exclusion of withdrawal symptoms and gaming tolerance from the criteria obviates the necessity of pharmacological measurements for determining these features, such as half-life or dosage, which are challenging.

Gaming tolerance and withdrawal-like symptoms, such as engaging in more intense gameplay [1•] or irritability from gaming abstinence [21], are clinically helpful in understanding a loss of control by gaming. ICD-11 lists and rewords these additional features to fit their clinical presentation without mentioning withdrawal or tolerance (Table 1). Previous empirical studies have reported these presentations, such as emotional responses from gaming abstinence [20, 21] which may affect GD assessments and diagnostic consistency.

Escapism is an essential motivating factor contributing to GD and should be included in clinical assessments. However, escapism is common among highly engaged, healthy gamers [23]. Thus, escapism has a lower diagnostic validity (69.6%) in identifying individuals with IGD [1•, 12]. Deception is also a criterion of gambling disorder in DSM-5 [2]. Only 44% of adults with GD deceive their parents or partner because most gaming patterns are chronic and well known by family members. Three other diagnostic studies have also reported the diagnostic validity of deception to be low [1•, 12, 24]. Further, experts agree that these two criteria have low importance in diagnostic validity and clinical utility and should be excluded from the criteria [14••]. Thus, ICD-11-GD criteria do not include deception and escapism.

Preoccupation with gaming is a DSM-5 criterion for IGD and is revised from the gambling disorder criteria in DSM-5 [2]. “The loss of interest in previous entertainment as a result of internet gaming” was listed in DSM-5-IGD based on Tao’s study [25]. ICD-11 does not include them in the criteria of GD. However, “the increasing priority given to gaming that gaming takes precedence over other life interests and daily activities” covers the concept of both preoccupation and loss of interest. The criteria might represent the progressive alteration in “motivation” for gaming and daily life. However, the agreements of experts on the importance of the criteria in clinical utility and prognostic value are relatively lower (< 80%) than other criteria in ICD-11 [14••]. Thus, the validity and utility of the new ICD-11-GD criteria should be evaluated, particularly in differentiating addiction from a healthy passion, in future studies [26].

Keeping gaming despite negative consequences is a crucial indicator of addiction and is listed in DSM-5-IGD and ICD-11-GD criteria. This criterion comprises two components: (1) negative consequences that result from excessive gaming and (2) continuing gaming despite negative consequences. The ICD-11-GD criteria include gaming despite negative consequences as a required criterion, but the DSM-5-IGD criteria do not. In addition to the psychological problems listed in the DSM-5-IGD criteria, unhealthy behavioral effects engendered by excessive gaming, including immobilization, inadequate sleep, disrupted circadian rhythms, lack of exercise, irregular diet, and obesity, have been reported to be frequent among individuals with GD [1•, 27••]. Thus, the ICD-11-GD criteria include adverse effects on health as one consequence. Moreover, the “substantial disruptions in diet, sleep, exercise and other health-related behaviours” are listed among the clinical features demonstrating gaming-related health problems.

According to DSM-5, five or more criteria should be met for 12 months before an IGD diagnosis can be made [2]. The cut-off point is a higher threshold than those established for other substance use disorders in DSM-5. In ICD-11, impaired control, prioritizing gaming, negative consequences, and functional impairment for 12 months or more are required for GD diagnosis [7]. Thus, its threshold was relatively higher than DSM-5-IGD criteria. Furthermore, the wording of ICD-11-GD criteria is analog to criteria for substance dependence in ICD-11, but not with DSM-5-IGD criteria. The wording of ICD-11-GD criteria is relatively broad and covers more individuals for potential treatment, such as “impaired control over gaming (e.g., onset, frequency, intensity, duration, termination, context).” The withdrawal-like symptoms (e.g., the inability to stop gaming) or tolerance (e.g., requiring more gaming than before) might satisfy ICD-11-GD criteria more broadly. Moreover, the broad definition might compensate for its higher threshold. A few studies have compared the thresholds for DSM-5-IGD and ICD-11-GD, as discussed subsequently.

The ICD-11-GD criteria also provide boundaries of normality to set a clinical threshold [7]. It suggests that a GD diagnosis cannot be determined based on only frequent gaming. Boundaries should be established for specific age groups, such as adolescent boys; for specific contexts, such as gaming during the holidays; for specific purposes, such as developing skills and proficiency in eSports; or for a particular peer group. In other words, the GD diagnosis should be based on the severity of clinical addiction and functional impairment, not simply the duration or frequency of gaming.

Ko et al. defined the severity of GD using a revised clinical global impression scale [28•]; the scale items are scored according to the severity of GD and the dimensions of functional impairment. In DSM-5, IGD is specified as mild, moderate, or severe, depending on the disruptions caused to daily life [2]. In ICD-11, GD is categorized based on online and offline gaming. Although most individuals with GD play online games, further research might be necessary to evaluate the clinical utility of online versus offline GD.

Moreover, ICD-11 highlights additional clinical features of GD to improve its clinical utility. For example, ICD-11 states that the duration required for diagnosing patients could shorten based on clinical severity. These clinical features include craving, impaired self-control, poor peer group dynamics, and comorbid psychiatric disorder [7].

In ICD-11-GD criteria, craving for games is an additional feature of GD [7]. Craving has been evaluated by brain imaging studies and revealed to possess clinical utility in preventive treatment [29,30,31]. Craving for games correlates with withdrawal-like symptoms, which are difficult to distinguish in clinical presentations [21]. Furthermore, individuals with GD and stronger cravings have difficulty maintaining abstinence from gaming [21]. A study suggested the inclusion of craving in the diagnostic criteria owing to its high diagnostic accuracy (88%) [12]. Listing craving in the additional features could benefit the clinical utility of the ICD-11 criteria and allow for testing its validity during diagnosis. Additionally, the ICD-11-GD criteria suggest that a craving for games can occur, while individuals are engaged in other activities [7]. However, we suggest that craving also frequently occurs under boredom. Further research is necessary to evaluate the onset of craving for games and the corresponding clinical implications.

The DSM-5-IGD criteria exclude gambling-related gaming, business work, social internet use, and sexual internet use [2]. The ICD-11-GD criteria include boundaries for hazardous gaming, gambling disorder, bipolar disorder, obsessive–compulsive disorder (OCD), and disorders due to substance use or psychoactive substance effect [7]. The core feature of compulsive behavior, experienced as inherently non-pleasurable and typically occurring in response to unwanted and generally anxiety-provoking obsessions, is well provided to differentiate itself from addictive gaming behavior [7]. Additionally, OCD is a comorbid psychiatric disorder of GD, and individuals with OCD may cope with their distress by using pleasure in gaming. However, if individuals must continue gaming to address their anxieties, such as repeatedly checking scores or items in their records, this gaming behavior should not be diagnosed as GD. Manic episodes should be excluded before GD diagnosis, as suggested by previous research [32•]. Apart from bipolar disorder, the prodromal symptoms of schizophrenia may cause adolescents to isolate themselves and continue online gaming to cope with stigmatism and psychosis [33]. Research should determine whether schizophrenia is another crucial differential diagnosis of GD among adolescents [32•].

The following disorders are comorbid psychiatric disorders listed in ICD-11-GD criteria: mood disorders, particularly depression [34]; anxiety or fear-related disorders, such as generalized anxiety disorder or social anxiety [34]; attention-deficit hyperactivity disorder [34]; OCD; and sleep–wake disorders, particularly delayed sleep phase disorder [1•]. The associations between psychiatric disorders and GD can be explained by four models: escape, negative consequence, bi-direction, and shared mechanism models [35]. For example, the escape model could explain the association between OCD and GD but not the shared mechanism model. Differential diagnoses in these disorders may prompt mental health professionals to evaluate the mechanisms of excessive gaming. It also makes them pay attention to the coexisted psychiatric disorders that require treatment simultaneously.

Furthermore, criteria related to course features, developmental presentations, and gender-related features are provided for diagnosing and treating adolescents and young adults, the two groups most susceptible to GD. In conclusion, the ICD-11-GD criteria provide much information that can help mental health professionals identify and treat individuals with GD. The information could be implemented in diagnostic studies to test their validity and utility.

Hazardous Gaming

Hazardous gaming is a “problems associated with health behaviours,” but not a disorder or disease [7]. Moreover, it is defined as “a pattern of gaming, either online or offline, that appreciably increases the risk of harmful physical or mental health consequences for the individual or others around this individual.” Similar to hazardous alcohol consumption, hazardous gaming was firstly listed in the ICD system for public health and prevention [19]. Additionally, it is considered a risky behavior requiring prevention from progression to addiction. It is not a disorder requiring treatment. The clinician should not pathologize individuals with hazardous gaming. According to the review by King et al., the government of South Korea initiated three levels of prevention (i.e., universal, selective, and indicated) for internet addiction. Non-profit organizations and private enterprises developed a prevention program for adolescents with GD [36]. The hazardous gaming criteria could facilitate identifying risky gaming behavior and implementing preventive intervention programs. Furthermore, its broad definition could compensate for the higher threshold of GD.

Comparing Diagnostic Validity and Clinical Utility of DSM-5-IGD Criteria, ICD-11-GD Criteria, and ICD-11 Criteria for Hazardous Gaming (ICD-11-HG)

A few studies have compared the validity of the DSM-5-IGD and ICD-11-GD criteria. Jo et al. (2019) evaluated adolescents and children who screened positive in screening tests, and they designed semi-structured interviews for diagnosis based on the DSM-5 criteria [37•]. They applied the ICD-11 criteria and diagnosed GD based on scores related to difficulty in self-control, decreased interest in other activities, persistent gaming despite negative consequences, and interference with role performance. Their results demonstrated that all participants who met the ICD-11-GD criteria (N = 12) also met the DSM-5-IGD criteria. However, 61 of 73 participants who met the DSM-5-IGD criteria did not meet the ICD-11-GD criteria. Therefore, the ICD-11-GD criteria had a higher threshold. Participants with ICD-11-GD had a higher rate of comorbidities associated with depressive disorder. Furthermore, participants with ICD-11-GD scored higher in all criteria except for deception and cravings. These results demonstrate that the ICD-11-GD criteria have a higher threshold and recruited patients with a higher clinical severity [37•].

Ko et al. evaluated the consistency between DSM-5-IGD and ICD-11-GD criteria among regular gamers by assessing nine DSM-5-IGD criteria involving frequency and severity thresholds [1•]. They observed that 63.8% of participants in the DSM-5-IGD group met the ICD-11-GD criteria and that 56.8% of those in the ICD-11-GD group experienced two or more dimensions of functional impairment. These results suggest that the ICD-11-GD criteria involve a higher threshold than the DSM-5-IGD criteria. The high threshold could attenuate the overdiagnosis (type I error) of GD. Furthermore, they recruited 36.2% of the participants in the DSM-5-IGD group and an additional 11 regular gamers (15.9%) to the hazardous gaming group because they experienced functional problems from gaming. Their results demonstrated that the hazardous gaming criteria might help clinical practitioners identify individuals who require preventive intervention but do not necessarily fulfill the GD criteria. Therefore, the hazardous gaming criteria can compensate for the high threshold of ICD-11-GD criteria.

In clinical settings, clinicians should diagnose GD among patients seeking treatment based on diagnostic criteria. Higuchi et al. (2021) applied the ICD-11 criteria to diagnose GD among 241 treatment-seeking patients [27••]. They observed that 78.4% and 83.0% of the treatment-seeking patients met the ICD-11-GD and DSM-5-IGD criteria, respectively. The ICD-11-GD criteria had high sensitivity (94%), specificity (97.6%), and positive predictive value (99.5%) for the DSM-5-IGD criteria. However, the negative predictive value was low (76.9%). Therefore, the ICD-11-GD has a relatively high threshold. Higuchi et al. also modified the ICD-11-GD criteria, suggesting that only two of the three criteria should be fulfilled [27••]. Consequently, the percentages of patients who met the criteria increased from 78.4 to 84.2%. Nonetheless, their study established higher consistency between the DSM-5-IGD and ICD-11-GD criteria for treatment-seeking patients with a relatively high disease severity level.

Ma et al. recruited 200 adolescent gamers to be interviewed by psychiatrists based on the ICD-11-GD and DSM-5-IGD criteria [38•]. The interrater consistency coefficient was 0.545 for ICD-11-GD and 0.622 for DSM-5-IGD, and the consistency coefficient between ICD-11-GD and DSM-5-IGD was 84.7%. These results demonstrate high diagnostic consistency between the ICD-11-GD and DSM-5-IGD criteria.

Castro-Calvo et al. evaluate the expert opinion on DSM-5-IGD and ICD-11-GD criteria [14••]. In DSM-5-IGD, experts agree on the validity and utility of the criteria for unsuccessful control, negative consequences, and functional impairment. However, criteria for escapism and tolerance did not own adequate validity in distinguishing IGD from the healthy gamer, particularly for highly engaged gamers. On the other hand, most experts agree on the diagnostic validity, clinical utility, and prognostic value of ICD-11-GD criteria except for criteria 2 (increasing priority). This study supports that ICD-11-GD could well identify individuals with GD to accept treatment [14••].

These prior empirical studies show a high consistency between the DSM-5-IGD and ICD-11-GD criteria. The ICD-11-GD criteria involve a higher threshold for identifying individuals with a higher severity level. Moreover, they demonstrate functional impairment among those diagnosed based on the ICD-11-GD criteria [1•, 27••]. The hazardous gaming criteria could identify individuals with risky gaming behavior and compensate for the higher threshold of ICD-11-GD. However, these studies did not discuss additional clinical features or boundaries with other disorders described in the ICD-11-GD criteria.

Further Research on GD Diagnostic Criteria

Diagnostic studies based on the ICD-11-GD criteria are still limited. Additional empirical studies involving diagnostic interviews or assessments are required to determine the clinical validity and utility of the criteria for the diagnosis, course, prognosis, and treatment of GD. These studies should pay much attention to criteria 2 of ICD-11, increasing priority given to gaming [14••]. Although ICD-11-GD criteria have a higher threshold design, whether the criteria could differentiate GD from highly engaged gaming behavior [26] deserves further study. Moreover, future diagnostic studies are required to test the clinical utility of additional clinical features or boundaries with other disorders mentioned in ICD-11.

In addition to the ICD-11-GD and DSM-5-IGD criteria, the research domain criteria proposed by the US National Institute of Mental Health assist in evaluating psychiatric disorders based on brain impairment in six domains: negative valence, positive valence, cognitive system, social processes, arousal/regulatory system, and sensorimotor system [39]. The US National Institute on Alcohol Abuse and Alcoholism proposed the addictions neuroclinical assessment in three domains: executive function, incentive salience, and negative emotionality, based on the neurobiological framework of addiction [40]. There is a heterogeneity of GD in terms of presentation, course, and complications. A treatment model is unable to satisfy the needs of all individuals. Comprehensive approaches are vital for developing an all-encompassing GD framework for research and clinical settings. A multidimensional approach that covers mechanisms such as cognitive control, emotional regulation, or rewarding vulnerability may assist in tailoring treatment to the needs of patients.

Gaming has transitioned from computers and consoles to mobile devices. Loot boxes, which provide random rewards similar to a lottery machine, are frequently used in mobile gaming. Identifying the similarities and differences between loot boxes and traditional gambling is a potential area for future research. Furthermore, whether mobile gaming could result in harmful physical consequences, such as traffic accidents due to impaired attention, or functional impairment, such as affecting an individual’s ability to cook, requires further research. As gaming continues to evolve through virtual reality gaming or more advanced artificial intelligence, its positive and negative effects on mental health will require research attention.

Conclusion

Limited empirical evidence supports the consistency between the DSM-5-GD and ICD-11-GD criteria. DSM-5-IGD criteria provide a way to identify individuals with IGD who require treatment and stimulate research on IGD. The ICD-11 criteria for GD and hazardous gaming provide a spectrum that can evaluate individuals with excessive gaming behavior to identify symptoms and provide appropriate treatment or prevention. Moreover, the ICD-11-GD criteria emphasize public health utility for mental health professionals. The ICD-11-GD criteria involve a higher diagnostic threshold, and patients with GD subsequently demonstrate higher disease severity levels. The hazardous gaming criteria could identify gamers with risky behavior and compensate for the possible type II errors associated with the ICD-11-GD criteria. Additional studies on the ICD-11-GD criteria are required to evaluate their clinical utility in terms of diagnosis, course, prognosis, and treatment.