International Journal ofEnvironmental Researchand Public HealthArticleThe Comorbidity of Gambling Disorder amongMacao Adult Residents and the Moderating Role ofResilience and Life PurposeJuliet Honglei Chen 1, Kwok Kit Tong 1 , Anise M. S. Wu 1,* , Joseph T. F. Lau 2 andMeng Xuan Zhang 11 Department of Psychology, Faculty of Social Sciences, University of Macau, Avenida da Universidade,Taipa, Macao, China; juliethchen@outlook.com (J.H.C.); kktong@um.edu.mo (K.K.T.);yb77304@connect.um.edu.mo (M.X.Z.)2 The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong,Hong Kong, China; jlau@cuhk.edu.hk* Correspondence: anisewu@um.edu.mo; Tel.: +853-8822-8377; Fax: +853-8822-2337Received: 11 November 2018; Accepted: 3 December 2018; Published: 7 December 2018Abstract: Macao, China’s only city with legalized casinos, has maintained a high prevalence ofgambling participation and gambling disorder (GD) over the past decade. The mental healthrisks associated with such high levels have been overlooked. In order to estimate the comorbidprevalence of GD with depression, anxiety, and Internet gaming disorder (IGD) and to explorethe potential buffering effect of psychological resilience and purpose in life, this study obtaineda representative adult Chinese sample (N = 1000, 44% male, aged 18–97 years) from a telephonesurvey conducted between October and November of 2016. As hypothesized, the highest psychiatriccomorbid prevalence was observed in the GD subgroup (n = 19, 21.1% probable IGD, 26.3% probabledepression, and 37.0% probable anxiety). All these mental health problems could increase one’sproclivity to GD, and vice versa. Psychological resilience was found to buffer the association betweenanxiety symptoms and probable GD (χ2(1) = 4.30, p = 0.04/GD symptoms, Fchange (1,162) = 6.29,p = 0.01), whereas purpose in life did not display any hypothesized moderating effect. These resultsindicate the usefulness of mental health screening for GD, taking into consideration its associatedrisks, and of fostering psychological resilience in prevention and treatment programs.Keywords: gambling disorder; Internet gaming disorder; depression; anxiety; comorbidity;prevalence; psychological resilience; purpose in life; Chinese; adults1. IntroductionMacao, with its reputation as the Las Vegas in the East and with its over 170 years of gamblingindustry history, is the only city in the greater China territory with legalized casino gambling since itssovereignty was returned to China, from Portugal, in 1999 [1,2]. Over the past 10 years, an estimated49.5% to 55.9% (N = 1963 to 2158) of its residents (≥ 15 years old) have participated in at least onegambling activity, of which 0.7% to 1.3% were identified as probable DSM-IV pathological gamblersin earlier years and 2.5% were identified as probable DSM-5 disordered gamblers in 2016 [3–6].Similar prevalence has been reported in other local studies, such as 5.6% probable pathologicalgambling in 2010 (N = 2011) [7] and 2.1% probable disordered gambling in 2014 (N = 1018) [8].These estimated percentages are considerably higher than those in other regions that have legalizedcasino gambling, such as a low 0.1% probable disordered gambling in Singapore (N = 3000) [9].The current study sought to make use of Macao’s solid residential gambling participation and toInt. J. Environ. Res. Public Health 2018, 15, 2774; doi:10.3390/ijerph15122774 www.mdpi.com/journal/ijerph
Int. J. Environ. Res. Public Health 2018, 15, 2774 2 of 13respond to an elevated call from the community to examine the risks associated with the high rates ofgambling disorder (GD), as well as to look for potential buffers.Other than demographic risks, such as male, younger, and with lower education levels [7,8,10], previous research has identified depression and anxiety as the two most frequently reportedforms of mental distress associated with being a gambler rather than a non-gambler [11–13]. In arecent systematic review of 11 general populations (N = 2417 to 43,093), an average comorbidity of37.9% for mood disorders (including major depression and bipolar disorder/manic episodes) and37.4% for anxiety were found to have gambling problems, including both problem gambling andpathological gambling [14]. Depression and anxiety in disordered gamblers were found to increasethe likelihood of health problems such as sleep disturbances [15], which are associated with riskbehaviors including substance use and lethal suicide attempts [16,17]. In another retrospective study(N = 9282), prior DSM-IV mood and anxiety disorders were found to predict the onset and persistenceof pathological gambling; 74.3% of the pathological gamblers with another lifetime mental disorderhad an earlier onset of at least one such disorder that preceded pathological gambling [10]. However,the local comorbidity of GD and emotional distress remains unstudied in Macao, hence, the potentialrisk of GD to the community’s mental health, and vice versa, is highly likely to be underestimated.The first objective of the present study was to estimate the comorbidity between GD and its two mostcommon forms of emotional distress (i.e., depression and anxiety) to provide more accurate statisticsfor clinical practice and community health promotion.When exploring the relationship between GD and other types of behavioral addictions, similaritiesbetween GD and Internet gaming disorder (IGD) were speculated and examined [18], with the lattereven being called a “nonfinancial form of gambling” (p.54) [19]. Although a positive relationshipbetween the two has been consistent [20,21], the comorbidity of the two appears to be an understudiedarea of inquiry. The only relevant study examined the comorbidity of video gaming dependenceand DSM-IV pathological gambling, which identified 15% of 193 treatment-seeking pathologicalgamblers as having video dependence [22]. On the other hand, Dowling and Brown, using anAustralian college sample (N = 173), reported that there was no overlap between problem gamblingand Internet dependence [23]. It is not clear whether the inconsistency in these findings is due to thedifferent samples or to the different diagnostic tools used. To fill the gaps in the existing literatureregarding DSM-5-based comorbidity between GD and IGD, our second objective was to examine thehypothesized co-occurrence between the two disorders in order to provide more empirical data forfurther comparisons by behavioral addiction scientists and practitioners.Our third objective was to explore the potential buffering effects of two personal strengthconstructs (i.e., psychological resilience and purpose in life) on the relationship between GD andits comorbidities to improve public health promotion and policy design efforts. Although no existingempirical studies have directly evaluated the moderating effects of these two, indirect evidenceindicates that resilience may play a protective role against problem gambling in the general populationand among adolescents [24,25]. Resilience has also been found to have a negative association withboth emotional distress and addictive behaviors, such as substance use [26]. In a grounded-theorystudy, Holdsworth reported that unlike recreational gamblers, problem gamblers appeared to lackthe resilience necessary to deal with life events and psychological comorbidities, which hints at thepossible protective role of resilience against GD and its comorbidities [27]. Purpose in life couldpotentially perform a similar buffering role, which was found indirectly from its negative correlationwith addictive behaviors, including problem gaming [28], Internet addiction [29], and smoking [30].To the best of our knowledge, no study has tested or documented the moderating effect of eitherpsychological resilience or purpose in life on the association between disordered gambling and othermental problems, such as emotional distress and IGD.Altogether, the present study hypothesized (a) the co-occurrence of GD with depression, anxiety,and IGD in the general population of Macao, and (b) the buffering effect of psychological resilienceand purpose in life on the relationship between GD and its comorbidities in Macao adult residents.
Int. J. Environ. Res. Public Health 2018, 15, 2774 3 of 13Our findings would (a) set the groundwork for subsequent DSM-5-based comorbidity studies of GD,(b) highlight the potentially increased risks of GD to draw the public’s attention to the need for earlyprevention and treatment, and (c) identify protective buffers that may alleviate the impact of comorbidpsychiatric symptoms (if any) of GD for practitioners and policy advocates.2. Materials and Methods2.1. Respondents and ProceduresBetween October and November of 2016, we conducted a random sampling telephone surveyamong Chinese Macao residents based upon the 2015 Macao residential phonebook. Both male andfemale Chinese Macao residents who were 18 years old or above were included. We adopted a two-stepstratified random sampling method of phone poll studies. We randomly selected eligible residentialunits in the first step, following which we selected a household member based on the last birthday rule.In the end, 1000 respondents voluntarily participated in and completed the approximate 12-minutephone survey without any monetary incentives, which incurred an overall 61.8% cooperation rate bythe standard of American Association for Public Opinion Research [31].The overall sample had more females (56%; 95% CI [52.9%, 59.1]), than males (44%; 95% CI [40.9%,47.1]), and a mean age of 40.0 years (SD = 15.3; ranging from 18 to 97), which was similar in sex and agedistribution to the population parameters of 2016 as reported by the census of Macao [32]. The sampleconsisted of 68.0% secondary or tertiary graduates, 66.9% full-time or part-time workers, and 11.9%casino employees. A total of 183 respondents who had engaged in gambling in the past 12 monthswere classified as “recent gamblers”.This study was part of a research project that had obtained approval from the ethics committee ofthe affiliated university of the corresponding author (MYRG2015-00213-FSS). Using the same dataset,the findings about prevalence and correlates of problematic adult gaming in Macao was reported inanother published paper [33].2.2. Measures SectionFor probable GD, consistent with previous studies [7,8,34], we used the nine DSM-5 diagnosticcriteria for GD to assess illness symptoms and identify probable disordered gamblers [35]. Onlyrespondents with past-year gambling experience (n = 183) answered whether each of the symptoms(e.g., preoccupation with gambling) described their own condition within the last year (0 = no, 1 = yes).Internal consistency (KR-20) of these items was 0.81 for the current sample. A total sum of the scalescore corresponded to the GD symptom variables (ranging from 0 to 9). A cutoff of 3/4 was used,in accordance with guidelines of the DSM-5 [35], to create the probable GD variable (1 = no, 2 = yes).Depression and anxiety symptoms were independently measured with two 7-item subscales fromthe Chinese version of the 21-item Depression Anxiety Stress Scales (DASS-21) [36]. It is with a 4-pointLikert scale, in which 0 = did not apply to me at all, and 3 = applied to me very much or most of the time.A total depression score (i.e., depression symptoms) and a total anxiety score (i.e., anxiety symptoms),which both ranged from 0 to 42, were computed. Higher total depression scores indicated moredepressive symptoms (Cronbach’s α = 0.82). Consistent with previous studies [37,38], respondentswith a score of ≥14 (moderate and above) were classified as probable depressed cases. Similarly, highertotal anxiety scores represented higher levels of anxiety (Cronbach’s α = 0.79), with a cut-off of ≥10(moderate and above) to classify probable cases with anxiety [37,38].Probable IGD symptoms were measured with the nine DSM-5 diagnostic criteria for thisdisorder [35], which is in accordance with previous research [39]. Only 473 self-reported past-yeargamers were asked to respond to these items about their experience of problematic gaming (0 = no,1 = yes) in the past 12 months (KR-20 = 0.69). The total sum scale score ranged from 0 to 9,which corresponded to the variables of IGD symptoms in the subsequent analyses. Another variable,
Int. J. Environ. Res. Public Health 2018, 15, 2774 4 of 13probable IGD, was computed, with a cutoff of 4/5, to differentiate probable IGD respondents fromnon-IGD respondents [40].Psychological resilience was measured via the 10-item Chinese version of the Connor–DavidsonResilience Scale [41,42]. It is a 5-point Likert scale, in which 0 = not true at all and 4 = true nearly all thetime. Higher scale scores indicated higher resilience levels, with the Cronbach’s α = 0.90 in this study.Perceived purpose in life was assessed with the 6-item version of Crumbaugh and Maholick’sPurpose in Life Scale with a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree) [43,44]. Higherscores reflected higher levels of positivity in perceived life purpose, with the Cronbach’s α = 0.82 inthis study.The background variables reported by respondents were their age, sex, education level,employment status, and casino employment status. Regarding gambling expenses, recent gamblerswere asked to decide how much they had spent during each gambling incident.2.3. Data AnalysisAll statistical analyses were conducted with SPSS 25.0 (IBM, Armonk, NY, USA) [45]. We firstexamined the descriptive statistics and inter-correlations of all the key variables and categorizedthe overall sample into two groups of sub-samples, namely, non-gamblers versus recent gamblersand non-GD gamblers versus probable GD gamblers. Multiple between-group comparisons wereconducted to explore potentially significant characteristic differences with χ2 tests and Mann–Whitneytests for categorically scaled (e.g., working status), ordinally scaled (e.g., educational attainment),or skewed variables (e.g., age), and t-tests were conducted for continuous variables. Based upon thesub-group comparison results, we calculated the Prevalence Ratio (PR = P (with diease)P (with exposure) ) to indicate thecomorbid risk of GD with depression, anxiety, and IGD.Finally, we explored the potential moderating effects of psychological resilience and purpose in lifeon the relationship between GD (i.e., probable GD and GD symptoms) and its three co-occurring mentalhealth problems (i.e., depression, anxiety, and IGD), respectively, with six hierarchical ordinary leastsquares linear regressions for GD symptoms and six hierarchical maximum likelihood binary logisticregressions for probable GD. In each hierarchical model, two well-established risky demographicfactors, age and gender [46], were controlled for as covariates in the first step. In the second step,the focal predictive variables (i.e., one comorbid symptom variable and one personal strength variable)were entered, and in the last step, the interaction term of the focal predictive variables was entered.All of the focal predictive variables and their product terms in these moderation models weremean-centered and bootstrapping (n = 5000) was performed to reduce bias [47].3. Results Section3.1. Profiles of this SampleThe overall sample (N = 1000) was categorized into non-gamblers (n = 817) versus recent gamblers(n = 187; with 168 non-GD gamblers [89.8%] and 19 probable GD gamblers [10.2%]). Table 1 showsthat males (OR = 2.96) and lower educational levels (OR = 1.47 [Junior secondary and lower versusSenior secondary and higher]) were more likely to engage in gambling in the past year. This patternwas also observed among probable GD gamblers compared to non-GD gamblers (OR = 3.04 for males;OR = 3.43 for less educated).Probable GD gamblers, relative to non-GD gamblers, reported spending significantly more moneyon gambling (p < 0.001) and showed a significantly higher tendency to suffer from IGD (OR = 12.53) andfrom depression (OR = 4.15). A similar online gaming engagement pattern was found among past-yeargamblers, in which they were more likely to play online games than non-gamblers, χ2(1) = 17.14,p < 0.001, OR = 1.98. However, it is worth noting that working in casinos did not significantlyaffect whether the respondents gambled in the past year (p = 0.97) or show probable GD (p = 0.22).
Int. J. Environ. Res. Public Health 2018, 15, 2774 5 of 13Non-gamblers and recent gamblers, moreover, did not have significantly different levels of probableIGD/anxiety/depression (p > 0.05).Table 1. Comparing Stratified Profiles of Overall Sample Subgroups and Gambler Subgroups.Overall Sample Subgroups Gambler SubgroupsNon-Gambler(n = 817)Recent Gambler(n = 183)Non-GD(n = 168)Probable GD(n = 19)Age U = 56297.00, z = −1.63, p = 0.10 U = 1075.50, z = −1.10, p = 0.27[M (SD)] 39.60 (15.39) 41.51 (15.11) 41.09 (14.87) 45.29 (17.13)Sex χ2(1) = 42.31, p < 0.001 χ2(1) = 3.26, p = 0.07[Male] 39.2% 65.6% 63.4% 84.2%Educational attainment U = 64558.00, z = −1.99, p = 0.05 U = 884.50, z = −2.56, p = 0.01Primary or below 13.1% 20.0% 17.7% 41.3%Junior secondary 15.1% 16.7% 16.0% 23.5%Senior secondary 28.3% 24.4% 25.2% 17.6%Tertiary 43.5% 38.9% 41.1% 17.6%Working status χ2(3) = 3.49, p = 0.32 χ2(3) = 1.39, p = 0.71Full-time 62.0% 65.2% 64.4% 72.2%Part-time 5.7% 7.7% 7.4% 11.1%Student 9.6% 6.1% 6.1% 5.6%Other 22.7% 21.0% 22.1% 11.1%Casino Employee χ2(1) = 0.002, p = 0.97 χ2(1) = 1.54, p = 0.22[Yes%] 11.6% 13.1% 13.7% 5.3%Gambling expense a − U = 671.50, z = −3.59, p < 0.001[Mdn] − $12.37–61.76 $12.37–61.76 $123.76–247.40Resilience t (996) = −0.10, p = 0.92 t (181) = 0.12, p = 0.91[M (SD)] 2.59 (0.67) 2.59 (0.68) 2.59 (0.68) 2.57 (0.70)Purpose in life t (998) = −0.90, p = 0.37 t (181) = 0.41, p = 0.69[M (SD)] 3.36 (0.64) 3.32 (0.61) 3.32 (0.60) 3.26 (0.65)Mental health problemsDepression χ2(1) = 0.48, p = 0.49 χ2(1) = 9.49, p = 0.01DASS < 14 [n (%)] 722 (88.4%) 165 (90.2%) 151 (92.1%) 14 (73.7%)DASS ≥ 14 [n (%)] 95 (11.6%) 18 (9.8%) 13 (7.9%) 5 (26.3%)Anxiety χ2(1) = 0.27, p = 0.61 χ2(1) = 2.54, p = 0.11DASS < 10 [n (%)] 648 (79.3%) 142 (77.6%) 130 (79.3%) 12 (63.2%)DASS ≥ 10 [n (%)] 169 (20.7%) 41 (22.4%) 34 (20.7%) 7 (36.8%)IGD b χ2(1) = 1.47, p = 0.23 χ2(1) = 13.44, p < 0.001DSM-5 < 5 [n (%)] 344 (96.4%) 104 (93.7%) 94 (96.9%) 10 (71.4%)DSM-5 ≥ 5 [n (%)] 13 (3.6%) 7 (6.3%) 3 (3.1%) 4 (28.6%)Note. GD—Gambling Disorder, IGD—Internet Gaming Disorder. a The gambling expense has been converted fromlocal currency to US dollars. b The total IGD sample (n = 468) includes only past-year online gamers.3.2. Comorbidity AnalysisIn the overall sample, the prevalence of probable GD, probable IGD, probable depression, andprobable anxiety was 1.9% (95% CI [1.05, 2.74]), 2.0% (95% CI [1.13, 2.87]), 11.3% (95% CI [9.34, 13.26]),and 20.1% (95% CI [17.62, 22.58]), respectively. When looking into the recent gambler subgroup(n = 183), the prevalence of all factors increased significantly, to 10.4% (95% CI [5.96, 14.80]) probableGD, 3.8% (95% CI [1.05, 6.60]) probable IGD, 9.8% (95% CI [5.52, 14.15]) probable depression, and 22.4%(95% CI [16.36, 28.45]) probable anxiety. The prevalence of these four mental health disorders peakedwithin the probable GD subgroup (n = 19), in which probable IGD was 21.1% (95% CI [2.72, 39.38]),probable depression was 26.3% (95% CI [6.52, 46.12]), and probable anxiety was 37.0% (95% CI [15.15,
Int. J. Environ. Res. Public Health 2018, 15, 2774 6 of 1358.53]). The Prevalence Ratio (PR) was further computed to depict the comorbid relationship betweenGD and the other three mental problems. Among the probable GD population, the PR of probable IGD,probable depression, and probable anxiety was 5.94, 3.27, and 2.02, respectively. Conversely, the PRof probable GD was 9.23, 3.32, and 1.78 in probable IGD, probable depression, and probable anxietysubgroups, respectively.3.3. Exploring Buffering Effects of Psychological Resilience and Purpose in LifeTable 2 presents the results of the analyses regarding the potential moderating effects ofpsychological resilience and purpose in life on the associations between GD (i.e., GD symptomsand probable GD) and each of the three comorbid disorder symptoms in the study. As shown, one setof six independent moderation models was built to assess the six product terms (i.e., depressionsymptoms × purpose, depression symptoms × resilience, anxiety symptoms × purpose, anxietysymptoms × resilience, IGD symptoms × purpose, and IGD symptoms × resilience) in moderatingbetween symptoms of depression/anxiety/IGD and GD symptoms. Similarly, another set of six modelswas examined for probable GD. The results showed no statistical significance for most of the interactionterms, with the exception of anxiety symptoms × resilience, which displayed a consistent moderatingeffect on the relationship between anxiety and GD symptoms (R2Change = 0.035, Fchange (1,162) = 6.29,p = 0.01) and between anxiety and probable GD (χ2(1) = 4.30, p = 0.04), respectively. We further probedthese moderating effects with a simple slopes analysis [48,49], and the results are presented in Figure 1.
Int. J. Environ. Res. Public Health 2018, 15, 2774 7 of 13Table 2. Exploring Potential Moderating Effects on GD Symptoms and Probable GD Models.Models GD Symptoms Probable GDModerating Effect Terms b [95% CI] a Interaction Effect OR [95% CI] a Interaction Effect1. Depression symptoms × purpose 0.04 [−0.04, 0.07] R2Change = 0.02, F (1,162) = 3.65, p = 0.06 1.08 [0.89, 1.17] χ2(1) = 3.30, p = 0.072. Depression symptoms × resilience −0.01 [−0.11, 0.03] R2Change = 0.001, F (1,162) = 0.18, p = 0.68 0.98 [0.86, 1.06] χ2(1) = 0.13, p = 0.723. Anxiety symptoms × purpose 0.03 [−0.07, 0.07] R2Change = 0.01, F (1,162) = 1.92, p = 0.17 1.06 [0.84, 1.17] χ2(1) = 1.86, p = 0.174. Anxiety symptoms × resilience −0.08 [−0.16, −0.004] R2Change = 0.035, F (1,162) = 6.29, p = 0.01 0.89 [0.79, 0.94] χ2(1) = 4.30, p = 0.045. IGD symptoms × purpose −0.01 [−0.72, 0.27] R2Change < 0.001, F (1,98) = 0.01, p = 0.92 1.29 [0.26, 2.27] χ2(1) = 1.06, p = 0.306. IGD symptoms × resilience −0.10 [−0.73, 0.16] R2Change = 0.004, F (1,98) = 0.44, p = 0.51 1.17 [0.38, 2.44] χ2(1) = 0.38, p = 0.54Note. GD—Gambling disorder, IGD—Internet Gaming Disorder. In each model, gender and age were controlled for as covariates, either GD symptoms or probable GD were tested as thedependent variable. All the focal predictive variables were mean-centered continuous variables. a Bootstrapping results were based on 5000 bootstrap samples. Biased-Corrected andaccelerated (BCa) bootstrap 95% confidence intervals (CI) were reported.
Int. J. Environ. Res. Public Health 2018, 15, 2774 8 of 13Int. J. Environ. Res. Public Health 2018, 15, x 8 of 13 (a) (b) Figure 1. Moderating effects of psychological resilience on the relationship between anxiety and (a) GD symptoms and (b) probable GD. The focal variables of anxiety symptoms and resilience were mean‐centered and adopted +1SD as the high point and –1SD as the low point, respectively. 00.20.40.60.811.21.41.61.82Low Anxiety High AnxietyGD symptomsLow Resilience High Resilience00.020.040.060.080.10.120.140.160.180.2Low Anxiety High AnxietyProbability of probable GDLow Resilience High ResilienceFig re 1. oderating effects of psychological resilience on the relationship between anxiety and (a) GD sympto s and (b) probable GD. The focal variables of anxietysymptoms and resilience were mean-centered a d adopted +1SD as the high point and –1SD as the low point, respectively.
Int. J. Environ. Res. Public Health 2018, 15, 2774 9 of 134. Discussion SectionIn this study, we collected a representative adult sample of the Macao community and observed 19probable GD gamblers, representing 10.4% (95% CI [5.96, 14.80]) in our past-year gambler sub-sample(n = 187), which is higher than the prevalence reported in other larger local gambler samples,such as 7.4% out of 282 past-year gamblers [8] and 4.9% of 1030 past-year gamblers [6]. Such ahigh prevalence of probable GD, reported across studies and time both in the general and gamblersamples, shows that gambling disorder is persistent and alarming in Macao, warranting furtherresearch and clinical attention.Our findings concerning the demographic profiles among recent gamblers and probable GDgamblers, such as males with lower educational attainment, are consistent with former localstudies [7,8]. The amount of gambling expense was consistently found to be a satisfactory indicator ofprobable GD gamblers when compared to non-GD gamblers, in this study and previous studies [8].However, casino employment no longer appeared to be a risk factor for probable GD, which might beattributed to the implementation of responsible gambling training programs for casino workers andlocal residents in recent years [50,51]. In addition, non-disordered gambling did not appear to increasethe risk for IGD, depression, or anxiety, as evidenced by the lack of significant results when comparingnon-gamblers with past-year gamblers. This finding lends some empirical support to the possibilitythat responsible gambling policy may reduce the potential harm of gambling on the public’s mentalhealth. However, further resources must be allocated to screening and treatment for those with GD orthose at-risk.When comparing the prevalence of probable IGD, probable depression, and probable anxietyin the three samples (i.e., the overall, the recent gambler, and the probable GD), the prevalenceof all three forms of mental health problems peaked in the probable GD sample. To quantify theincreased risk level, we calculated PR for further comparison. As a result, compared to the non-GDgroup, people with GD were 5.94 times, 3.27 times, and 2.02 times more likely to have probableIGD, probable depression, and probable anxiety, respectively. In contrast, the risk of having probableGD would be 9.23 times more likely among probable IGD cases when compared to non-IGD cases,3.32 times more likely among probable depression cases when compared to non-probable depressioncases, and 1.78 times more likely among probable anxiety cases when compared to non-probableanxiety cases. These data confirmed the co-occurrence of these mental problems and provided extrasupport to previous studies’ claims regarding positive correlations between GD and other mentalhealth disorders [10]. They also confirmed that problem gambling could be initiated by depressionand anxiety [52].Although the mutual risks of having probable GD in emotionally distressed populations andhaving emotional distress in probable GD populations are comparable, probable IGD cases were foundto be at a much higher risk of suffering from probable GD (PR = 9.23) than probable GD cases were ofsuffering from probable IGD (PR = 5.94). In addition to the likelihood of a high co-occurrence, due tosimilar mechanisms for the development of these two types of behavioral addictions, our findings mayalso reflect the notion that IGD may be a “gateway illness” for GD development. Further empiricalevidence is needed to confirm this speculation. The findings may also be attributed to differentdeterminants involved in the development of these two behavioral addictions, which may be relatedto gambling’s essential financial elements [18], as well as to gaming pursuits placing more focus onskill [53].A statistically significant buffering effect was found only in relation to psychological resilience,which moderated the relationship between anxiety symptoms and probable GD (in both binaryand continuous forms). Specifically, even after controlling for the effects of age and gender, thebuffering effects of psychological resilience still explained 3.5% of the variance in the associationbetween anxiety and GD symptoms, and decreased the risk of having probable GD from anxietyby 0.89 times (Bias-Corrected and accelerated [BCa] bootstrap 95% CI [0.73, 0.98]). From the twosimple probing analyses in the figures, we inferred that those with higher levels of resilience had
Int. J. Environ. Res. Public Health 2018, 15, 2774 10 of 13a lower probability of suffering from GD symptoms and being a probable GD gambler, even whenanxiety levels were high. Given that similar buffering patterns were found in both GD symptoms andprobable GD, we inferred that the protective effect of resilience can work for both general gamblers andprobable GD gamblers. This finding also extended the protective function of psychological resilienceto probable GD gamblers from previously discovered recreational gamblers [27]. However, a similarbuffering effect of psychological resilience was not found in the relationship between depression andGD symptoms/probable GD. One plausible reason for lacking a buffering effect on depression isthat depression, compared to anxiety, might be non-linearly related to GD symptoms/probable GD.For example, in a two-year longitudinal study of 6067 casino employees, respondents who gambledand had severe and disabling depression (i.e., presenting dysfunctions at work or in personal life for atleast two weeks over the past six months) reported a reduced level of gambling problems about oneyear later [54]. It is possible that gamblers with serve depression may be less responsive to externalinfluences (including stressors), probably because of their low energy levels, and thus psychologicalresilience may also lose its buffering role. Further research is needed to understand the mechanismsunderlying the GD-depression relationship and to identify potential buffers in such relationship.The buffering effects of purpose in life on the relationships between GD symptoms/probable GDand any of its comorbidities were not observed. A plausible reason was that its buffering effect wascancelled out by other uncontrolled confounding variables. One possible confounding variable was theextent to which people search for meaning in life. A previous study showed that the predictive valueof meaning/purpose on anxiety and perceived health disappeared among the respondents reporting alow level of search for meaning [55]. Thus, we would call for more replication studies examining thepotential protective roles of not only purpose in life but also psychological resilience, their relationshipswith GD, and their comorbidities after considering other possible confounding variables.Although we found a co-occurrence of GD with several mental health problems and discoveredsome promising future directions, our study presented several limitations that are worth noting. First,although we found a co-occurrence of probable GD, probable IGD, probable depression, and probableanxiety, and calculated a PR for each condition, causal inferences cannot be made because we didnot have control over the precedence of any of the events or conditions in this correlational study.Longitudinal studies are strongly recommended to further explore which conditions appear to emergefirst with regard to GD and its psychiatric comorbidities. Second, collecting data in the form of atelephone survey is a double-edged sword. Although this methodology assured a representativesample, only non-clinical diagnostic tools were used in this survey and they were only able to identifyprobable cases of the concerned mental disorders. The fact that the survey was administrated overthe telephone necessarily set restrictions on length. Hence, we had to choose shorter versions of thescales and sacrificed other valuable constructs, such as search for meaning. Third, although we tried tominimize the self-report bias by assuring respondents of the anonymous nature of the survey at thebeginning of each phone interview, there may still have been some lingering effects of self-report biasin our findings, which may also occur in other survey studies using self-report methods.5. ConclusionsAs the first DSM-5 criteria comorbidity study of probable GD with probable depression/anxiety/IGD in a representative Chinese adult sample, this study underscores the increasedsusceptibility to developing other mental disorders among probable GD gamblers and thus providespractical insights for mental health screening and prevention for practitioners and policy makers.Specifically, assessment of GD, IGD, depression, and anxiety are recommended to be conductedtogether in general population screenings and in psychiatric diagnostic interviews of GD gamblers.The designers of GD intervention programs should be aware of any co-occurred psychological distressand problem gaming patterns and adopt a more integrated approach that addresses not only GD butalso its co-morbidity, simultaneously. The buffering effect of psychological resilience between anxietyand GD symptoms/probable GD sheds light on the potential usefulness of fostering psychological
Int. J. Environ. Res. Public Health 2018, 15, 2774 11 of 13resilience as part of prevention and treatment programs. In addition to testing the replicability of thecurrent findings, future studies should also investigate the underlying mechanism between GD andother mental disorders, and the effectiveness of interventions that incorporate the factors examined inthis study.Author Contributions: Conceptualization, J.H.C., K.K.T., A.M.S.W., and J.T.F.L.; data curation, J.H.C. andA.M.S.W; formal analysis, J.H.C.; funding acquisition, K.K.T., A.M.S.W., and J.T.F.L.; methodology, J.H.C., K.K.T.,and A.M.S.W.; project administration, K.K.T. and A.M.S.W.; resources, A.M.S.W.; supervision, K.K.T. and A.M.S.W.;validation, J.H.C. and K.K.T.; visualization, J.H.C. and M.X.Z.; writing—the original draft, J.H.C. and A.M.S.W.;writing—review and editing, J.H.C., K.K.T., A.M.S.W., J.T.F.L. and M.X.Z.Funding: The project was supported by a research grant from the University of Macau (Ref # MYRG2015-00213-FSS).Conflicts of Interest: The authors declare no conflicts of interest.References1. Chan, P.K.; Chan, P.C. Gaming Industry and its Opportunities for Development; Keng Vai: Macao, China, 2001.2. Wu AM, S.; Lau JT, F. Gambling in China: Socio-historical evolution and current challenges. Addiction 2015,110, 210–216. [CrossRef] [PubMed]3. Institute for the Study of Commercial Gaming (ISCG). Report on a Study of Macao People’s Participation inGambling Activities 2007; ISCG: Taipa, Macao, China, 2008.4. Institute for the Study of Commercial Gaming (ISCG). Report on a Study of Macao People’s Participation inGambling Activities 2010; ISCG: Taipa, Macao, China, 2010.5. Institute for the Study of Commercial Gaming (ISCG). Report on a Study of Macao People’s Participation inGambling Activities 2013; ISCG: Taipa, Macao, China, 2014.6. Institute for the Study of Commercial Gaming (ISCG). Report on a Study of Macao People’s Participation inGambling Activities 2016; ISCG: Taipa, Macao, China, 2016.7. Fong, D.K.-C.; Ozorio, B. Gambling participation and prevalence estimates of pathological gambling in afar-east gambling city: Macao. UNLV Gaming Res. Rev. J. 2005, 9, 15–28.8. Wu, A.M.S.; Lai, M.H.C.; Tong, K.K. Gambling disorder: Estimated prevalence rates and risk factors inMacao. Psychol. Addict. Behav. 2014, 28, 1190–1197. [CrossRef] [PubMed]9. National Council on Problem Gambling (NCPG). Report of Survey on Participation in Gambling Activities amongSingapore Residents 2017; NCPG: Singapore, 2018. Available online: https://www.ncpg.org.sg/en/pdf/Report_on_NCPG_Gambling_Participation_Survey_2017_final.pdf (accessed on 5 December 2018).10. Kessler, R.C.; Hwang, I.; LaBrie, R.; Petukhova, M.; Sampson, N.A.; Winters, K.C.; Shaffer, H.J. DSM-IVpathological gambling in the National Comorbidity Survey Replication. Psychol. Med. 2008, 38, 1351–1360.[CrossRef] [PubMed]11. Boughton, R.; Falenchuk, O. Vulnerability and comorbidity factors of female problem gambling.J. Gambl. Stud. 2007, 23, 323–334. [CrossRef] [PubMed]12. Cunningham-Williams, R.M.; Cottler, L.B.; Compton WM, I.I.I.; Spitznagel, E.L. Taking chances: Problemgamblers and mental health disorders-results from the St. Louis Epidemiologic Catchment Area Study. Am. J.Public Health 1998, 88, 1093–1096. [CrossRef] [PubMed]13. El-Guebaly, N.; Patten, S.B.; Currie, S.; Williams, J.V.A.; Beck, C.A.; Maxwell, C.J.; Wang, J.L. Epidemiologicalassociations between gambling behavior, substance use & mood and anxiety disorders. J. Gambl. Stud. 2006,22, 275–287. [CrossRef]14. Lorains, F.K.; Cowlishaw, S.; Thomas, S.A. Prevalence of comorbid disorders in problem and pathologicalgambling: Systematic review and meta-analysis of population surveys. Addiction 2011, 106, 490–498.[CrossRef]15. Parhami, I.; Siani, A.; Rosenthal, R.J.; Lin, S.; Collard, M.; Fong, T.W. Sleep and gambling severity in acommunity sample of gamblers. J. Addict. Dis. 2012, 31, 67–79. [CrossRef]16. Pompili, M.; Innamorati, M.; Forte, A.; Longo, L.; Mazzetta, C.; Erbuto, D.; Ricci, F.; Palermo, M.; Stefani, H.;Seretti, M.E.; et al. Insomnia as a predictor of high-lethality suicide attempts. Int. J. Clin. Pract. 2013, 67,1311–1316. [CrossRef]
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