COMMENTS: Unique longitudinal study. Found that pathological gambling can lead to mood disorders, PTSD, anxiety, and other addictions, 3 years later. In other words, addiction can cause mood disorders, rather than mood disorders manifesting as addiction. We must be very cautious to assume that mood and mental problems are always pre-existing.
Am J Epidemiol. 2011 Jun 1; 173(11): 1289–1297.
Published online 2011 Apr 5. doi: 10.1093/aje/kwr017
This article has been cited by other articles in PMC.
The authors’ objective in this study was to examine the role of disordered gambling as a risk factor for the subsequent occurrence of specific Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I psychiatric disorders after adjusting for medical conditions, health-related quality of life, and stressful life events. Community-dwelling respondents from nationally representative US samples (n = 33,231) were interviewed in 2000–2001 and 2004–2005.
Past-year disordered gambling at baseline was associated with the subsequent occurrence of any Axis I psychiatric disorder, any mood disorder, bipolar disorder, generalized anxiety disorder, posttraumatic stress disorder, any substance use disorder, alcohol use disorders, and alcohol dependence disorder after adjustment for sociodemographic variables.
After simultaneous adjustment for medical conditions, health-related quality of life, and recent stressful life events, disordered gambling remained significantly related to any mood disorder, generalized anxiety disorder, posttraumatic stress disorder, alcohol use disorders, and alcohol dependence. The clinical implications of these findings are that treatment providers need to screen gambling patients for mood, anxiety, and substance use problems and monitor the possible development of later comorbid conditions.
Pathologic gambling, characterized by a preoccupation with gambling, loss of control, “chasing” losses, and continued gambling, is one of the impulse control disorders in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Based on community surveys, the prevalence estimates for lifetime pathologic gambling have been reported to range from 0.4% to 4.0% in the United States (1–3). This classification typically refers to persons who meet at least 5 of the DSM-IV criteria for pathologic gambling (4). “Problem gambling” is a term used to describe gambling behavior that meets only 3 or 4 DSM-IV criteria rather than 5 criteria, indicating that the gambling behavior is problematic but falls short of a pathologic gambling diagnosis. A recent epidemiologic survey suggested that approximately 2.5% of the population in the United States and Canada would meet criteria for problem gambling (5). Both problem and pathologic gambling are associated with substantial costs for individuals, their families, and society (6, 7); therefore, from a public health perspective, it is essential to examine these 2 gambling behaviors. Thus, in this study we considered problem and pathologic gambling together (i.e., disordered gambling) as the extreme end of a behavioral continuum of gambling, which has been done in previous studies (8, 9).
Although previous studies have suggested a link between disordered gambling and DSM-IV Axis I psychiatric disorders (1, 2, 10, 11), the cross-sectional nature of the data used in those studies precluded the investigators’ ability to establish the temporal order between disordered gambling and psychiatric disorders, although one of those studies used retrospective age of onset to establish temporal order (2). In addition, because disordered gambling is associated with impaired functioning (12, 13), reduced quality of life (12–14), specific medical conditions (12), and high rates of encountering stressful life events like unemployment, divorce, and bankruptcy (7), these same factors have also been found to be associated with Axis I disorders (15–17). Therefore, because these factors may have an impact on disordered gambling and Axis I disorders, it is important that these potentially confounding factors be controlled for in analyses evaluating the relations between disordered gambling and psychiatric disorders. To date, cross-sectional studies have not adjusted for these important factors (1, 2, 10). To fill in these gaps, we aimed to assess the association of past-year disordered gambling with the incidence of Axis I psychiatric disorders at follow-up 3 years later, after adjusting for sociodemographic variables, medical conditions, health-related quality of life, and stressful life events.
MATERIALS AND METHODS
We used data from waves 1 (2000–2001) and 2 (2004–2005) of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Wave 1 of the NESARC surveyed a representative sample of 43,093 civilians aged 18 years or older residing in US households, oversampling black and Hispanic people and young adults aged 18–24 years (18, 19). After exclusion of respondents who were ineligible for the wave 2 interview because they had died (n = 1,403), had been deported or were mentally or physically impaired (n = 781), or were on active duty in the armed forces throughout the follow-up period (n = 950), wave 2 was conducted 3 years later; the response rate was 86.7%, reflecting 34,653 completed face-to-face interviews. Wave 2 data were weighted to reflect the design characteristics of the NESARC, accounting for oversampling, nonresponse, and the presence of any lifetime wave 1 NESARC substance use or other psychiatric disorder; this adjustment was performed at both the household level and the individual level (20). Weighted data were then adjusted to be representative of the civilian population of the United States with regard to socioeconomic variables on the basis of the 2000 decennial US Census. Because of missing values for some variables examined in this study, we focused on 33,231 subjects in this analysis.
DSM-IV diagnoses of psychiatric disorders were assessed with the Alcohol Use Disorder and Associated Disabilities Interview Schedule—DSM-IV Version (AUDADIS-IV) (21), wave 2 version (22), which was developed for use by trained lay interviewers. Axis I psychiatric disorders were examined identically in the waves 1 and 2 versions of the AUDADIS-IV, except for the time frames. Lifetime and 12-month diagnoses of psychiatric disorders were obtained in wave 1, while 12-month and 3-year diagnoses of disorders were calculated in wave 2. In the analysis of incidence, only those respondents who did not have a life diagnosis of the disorder in question at baseline were included in the analysis, and the main dependent variable was 3-year diagnosis of that disorder at wave 2. No diagnostic hierarchy rules were applied in either wave, except that hierarchical diagnoses were used for major depressive disorder and bipolar disorder.
In waves 1 and 2, DSM-IV primary mood disorders included major depressive disorder, dysthymic disorder, and bipolar (I or II) disorder. Anxiety disorders included panic disorder (with or without agoraphobia), social and specific phobias, generalized anxiety disorder, and posttraumatic stress disorder (PTSD). The AUDADIS-IV methods used to diagnose these disorders are described in detail elsewhere (21, 23–28). Test-retest reliabilities (kappa values) for AUDADIS-IV diagnoses of mood and anxiety disorders in the general population and clinical settings ranged from fair to good (κ = 0.40–0.77) (29–31). Convergent validity was good to excellent for all mood and anxiety diagnoses (21, 24–26, 28, 32–34), and these diagnoses indicated good agreement (κ = 0.64–0.68) with psychiatrist reappraisals (29).
The extensive questioning in the AUDADIS-IV covered the DSM-IV criteria for nicotine dependence, alcohol and drug-specific abuse, and dependence on 10 classes of substances (amphetamines, opioids, sedatives, tranquilizers, cocaine, inhalants/solvents, hallucinogens, cannabis, heroin, and other drugs). A DSM-IV abuse diagnosis necessitated the presence of 1 or more of 4 abuse criteria, whereas a DSM-IV dependence diagnosis demanded that 3 or more of 7 dependence criteria be met. The test-retest reliability of AUDADIS-IV diagnoses of substance use disorders has been found to be good to excellent (κ = 0.70–0.91) in clinical and general population samples (29–31, 35–37). The good-to-excellent convergent, discriminant, and construct validity of AUDADIS-IV substance use disorders criteria and diagnoses has been well documented (38–41), including documentation in the World Health Organization/National Institutes of Health International Study on Reliability and Validity (42–47), where clinical reappraisals demonstrated good validity of DSM-IV alcohol and drug use disorder diagnoses (κ = 0.54–0.76) (29, 42).
Data on whether or not the respondent had disordered gambling were obtained using 10 DSM-IV diagnostic inclusionary criteria for pathologic gambling. Consistent with previous studies using the NESARC data (10, 48–51), a 12-month disordered gambling diagnosis required the respondent to have met at least 3 criteria in the previous year and to have reported gambling at least 5 times in the past year. All respondents who were not classified as having disordered gambling were categorized as nondisordered gamblers, including those who had not gambled at all in their lifetime. The internal consistency of all symptom items and criteria for pathologic gambling were excellent, and the validity of the scale was established (1).
Sociodemographic variables, including sex, age, marital status, educational level, race/ethnicity, household income, and employment status at wave 1, were included in the models. In addition, medical conditions, health-related quality of life, and stressful life events at wave 1 were also included as confounding factors in the models. The NESARC examined past-year prevalence of 11 medical conditions: arteriosclerosis, hypertension, cirrhosis, other liver diseases, angina, tachycardia, myocardial infarction, other heart diseases, stomach ulcer, gastritis, and arthritis. Respondents were asked whether a physician or other health-care professional had diagnosed the condition. Health-related quality of life was assessed using the Short Form 12 Health Survey—Version 2 (SF-12) (52). Physical and mental health SF-12 component summary measurements were calculated. A list of 12 recent stressful life events (occurring in the past year prior to wave 1) was also included. The 12 stressful life events were: the death of a family member or close friend; serious illness or injury in a family member or close friend; moving to a new home or having new household members; being fired or laid off from a job; being unemployed and looking for a job for more than 1 month; having trouble with a boss or coworker; experiencing a change in one’s job, job responsibilities, or work hours; becoming separated or divorced or breaking off a steady relationship; having a problem with a neighbor, friend, or relative; experiencing a major financial crisis; getting into trouble with the police, being arrested, or being sent to jail (either the participant or a family member); and being the victim of a crime (either the participant or a family member).
Weighted percentages were computed to derive the sociodemographic characteristics of respondents with and without disordered gambling. Logistic regression models were fitted to assess the association of disordered gambling with all sociodemographic characteristics. In addition, 5 sets of logistic regression models were used to examine the associations between past-year disordered gambling at baseline and the incidence of mood, anxiety, and substance use disorders during the 3-year follow-up period of wave 2 (i.e., only the respondents who did not have a lifetime diagnosis of the disorder in question at wave 1 were included in the analysis). The first models adjusted only for the sociodemographic characteristics assessed in this study. Besides sociodemographic characteristics and lifetime diagnosis of the disorder in question, the second, third, and fourth models further adjusted for the presence of the 11 medical conditions, SF-12 physical and mental health component summary scores, and the 12 stressful life events, respectively. The final model simultaneously included all of the covariates mentioned above.
Data were analyzed with SUDAAN 9.0 (Research Triangle Institute, Research Triangle Park, North Carolina), a software program that uses Taylor series linearization to adjust for the design effects of the NESARC’s complex sampling method. To adjust for multiple statistical tests, we set the significance level for all tests at P < 0.01 to reduce type I error and increase the likelihood that the effects would be replicated in future studies. All standard errors and 99% confidence intervals were adjusted for the design effects of the wave 2 NESARC sample.
The overall prevalence of disordered gambling in the study was 0.60% (99% confidence interval: 0.51, 0.71). The prevalences of disordered gambling among male and female respondents were 0.82% (99% confidence interval: 0.66, 1.02), and 0.40% (99% confidence interval: 0.30, 0.53), respectively. Table 1 presents the distribution of sociodemographic variables among persons with and without disordered gambling. Logistic regression revealed statistically significant differences between disordered and nondisordered gamblers for sex, education, and race/ethnicity. Being female decreased the odds of disordered gambling. With regard to educational level, having a university education, compared with having less than a high school education, decreased the odds of disordered gambling. Lastly, being Hispanic relative to being white was also associated with decreased odds of disordered gambling. Statistically significant differences were not found for age, marital status, household income, or employment status.
Table 2 presents the odds ratios for the relation between past-year disordered gambling, as measured at wave 1, and the incidence of Axis I psychiatric disorders during the 3-year follow-up period. After adjustment for sociodemographic characteristics measured at wave 1, persons who reported past-year disordered gambling were significantly more likely to have new onset of any Axis I psychiatric disorder, any mood disorder, bipolar disorder, generalized anxiety disorder, PTSD, any substance use disorder, alcohol use disorder, and alcohol dependence disorder during the 3-year follow-up period. The association of disordered gambling with bipolar disorder became nonsignificant after further adjustment for the presence of 11 medical conditions at wave 1. The significant relations of disordered gambling with bipolar disorder and any substance use disorder were no longer statistically significant after further adjustment for SF-12 physical and mental health component summary scores.
When we adjusted for encountering any of the 12 stressful life events during the year prior to wave 1, the relations between disordered gambling and any Axis I disorder, bipolar disorder, and any substance use disorder became nonsignificant. In the final models simultaneously adjusting for sociodemographic variables, the presence of 11 medical conditions, SF-12 physical and mental health component summary scores, and the 12 stressful life events, disordered gambling remained significantly associated with any mood disorder, generalized anxiety disorder, PTSD, alcohol use disorders, and alcohol dependence.
Several cross-sectional studies have found a significant association between disordered gambling and DSM-IV Axis I psychiatric disorders (1, 2, 10, 11, 51). The current research is novel because it extends our understanding of disordered gambling comorbidity with the use of a nationally representative, longitudinal, prospective study design while concurrently adjusting for several potentially confounding variables known to be linked with gambling problems and psychiatric disorders. The key findings from this study are that 1) past-year disordered gambling at wave 1 was associated with increased odds of the incidence of some Axis I psychiatric disorders at follow-up 3 years later and 2) the majority of significant relations remained significant after concurrent adjustment for potentially confounding variables, including sociodemographic factors, medical conditions, reduced health-related quality of life, and stressful life events.
In the current study, disordered gambling only predicted the incidence of some psychiatric disorders—specifically, bipolar disorder, generalized anxiety disorder, PTSD, alcohol use disorder, and alcohol dependence disorder, as well as any Axis I disorder, any mood disorder, and any substance use disorder. With a few exceptions (any Axis I disorder, any substance use disorder, and bipolar disorder), these significant relations remained even after we concurrently adjusted for all confounding variables; the confounding variables did not account for the variance in these relations and were unable to explain the relation between disordered gambling and incident Axis I psychiatric disorders. These findings suggest that the occurrence of disordered gambling may be more likely to predict later incidence of any mood disorders, generalized anxiety disorder, PTSD, and alcohol use or dependence and less likely to precede depression, dysthymia, panic disorder, social phobia, specific phobia, nicotine dependence, and drug use disorders. The possible explanations for these patterns in the findings are beyond the scope of the current data, but future investigations into the underlying mechanism would be of interest.
These findings are similar to those of a prior investigation of the temporal relation between problem gambling and Axis I disorders that used cross-sectional data and retrospective age-of-onset information (2). In that study, it was found that problem gambling predicted bipolar disorder, PTSD, any anxiety disorder, alcohol or drug dependence, nicotine dependence, any substance use disorder, and any disorder after adjustment for age, sex, and race/ethnicity, despite the fact that these findings should be interpreted with caution because of the reliance on cross-sectional retrospective data. Although general consistencies are noted between this previous study (2) and the current findings, the current study furthers our understanding of the relation between disordered gambling and Axis I disorders with the use of longitudinal, prospective data, the inclusion of several potentially confounding variables, and the examination of alcohol and drug use disorders separately.
Notably, the relation between disordered gambling and alcohol use disorders was robust in nature in all incident models. However, a significant relation between disordered gambling and incident drug use disorders was not found in any models. These findings draw attention to the importance of studying alcohol and drug use in separate groups rather than examining only a broad substance use category. The relations between disordered gambling and alcohol and drug use may not be the same, which has important implications for public health policies regarding regulations on gambling and alcohol consumption. It may be that alcohol use more commonly co-occurs with gambling in comparison with drug use, because alcohol is a legal substance often sold at gambling venues. Some gambling venues allow alcohol consumption while gambling and other venues restrict alcohol consumption to designated nongambling areas, allowing the gambler to consume alcohol before or after gambling. The joint access to gambling and alcohol may partly explain why disordered gambling was only linked to increased odds of incident alcohol use disorders and not incident drug use disorders. A general substance use category alone would be unable to detect the possible differences in these relations.
From a public health perspective, findings from this study are important because they indicate that gambling problems can lead to later incidence of some psychiatric disorders. Losing control of one’s gambling behavior and developing disordered gambling can create significant stress in a person’s life. People who experience significant gambling problems often report tribulations such as spending more money on gambling than intended, being unable to cut down on or quit gambling, and using gambling to forget about problems or depressed feelings, and they often report that gambling has caused problems with friends and family (53). Stresses related to disordered gambling may create significant affective and anxious feelings that could lead to some incident mood, anxiety, and substance use disorders. Similarly, for some persons gambling may be a poor coping mechanism for dealing with emotional problems, including depressed or anxious feelings, which in turns exacerbates the problems and symptoms, leading to meeting criteria for other Axis I psychiatric disorders.
Further research on the temporal relation between disordered gambling and Axis I psychiatric disorders is necessary because it is also possible that Axis I psychiatric disorders may develop before or concurrently with gambling problems. Little information is available regarding the temporal association of this relation (54). For example, one recent study found that depression was just as likely to occur before the development of gambling problems as afterward (55), suggesting that some persons may use gambling as a poor coping mechanism to relieve dysphoric mood, while others may become depressed because of their gambling problems. Kessler el al.’s (2) 2008 study indicated that in addition to problem gambling’s predicting some mood, anxiety, and substance use disorders in some cases, pathologic gambling was also found to develop after several DSM-IV psychiatric disorders, including anxiety, mood, impulse-control, and substance use disorders, for some persons. Examination of the reciprocal relation of Axis I psychiatric disorders with disordered gambling was not possible in the current study, because gambling was assessed only at baseline. This is a notable limitation of the current study.
The strengths of the current research include the use of a large, nationally representative sample; the longitudinal and prospective study design; face-to-face interviewing methods; the inclusion of reliable and valid diagnostic tools; and concurrent adjustment for several potentially confounding variables. However, findings from the current study should be considered in light of several important limitations. First, all psychiatric disorder diagnoses were made by means of a reliable structured interview conducted by trained lay interviewers, yet this assessment approach may not match the accuracy of an assessment made by an experienced clinician. Second, medical conditions were based on self-reports of physician-diagnosed conditions and were not confirmed from independent sources. Although this procedure has been used in other gambling research (56), it is possible that some persons reported a medical condition that would not have matched a physician’s diagnosis. Additionally, underreporting of some conditions may have occurred if a respondent had the condition but had not yet been given a physician’s diagnosis. Eleven medical conditions were assessed in these data, but this does not represent a comprehensive list. Third, several stressful life events were assessed in the current data, but the list of stressful life events is not considered exhaustive. Fourth, assessment of disordered gambling at baseline only did not allow for examination of the reciprocal relation of Axis I psychiatric disorders with incident or persistent disordered gambling. Finally, lifetime diagnoses of psychiatric disorders were assessed at baseline as one of the covariates used in our analyses, but the lifetime diagnoses were retrospectively self-reported and thus were susceptible to recall bias.
Findings from the current research have important clinical implications. The results from this study provide evidence that disordered gambling can lead to incident and persistent Axis I psychiatric disorders and that these significant relations cannot be explained by sociodemographic variables, medical conditions, reduced health-related quality of life, or stressful life events. Treatment providers need to screen gambling patients for mood, anxiety, and substance use problems and monitor symptoms for possible development of later comorbid conditions. Because gambling problems and comorbid Axis I psychiatric disorders may be linked, it is likely that treatment effectiveness would be limited if gambling problems were treated in isolation when other psychiatric symptoms or disorders, including mood, anxiety, and substance use disorders, were present. For some persons, gambling may create affective or anxiety symptoms or the desire to drink alcohol to cope with problems. Intervention efforts to manage gambling behavior alone without addressing related affective symptoms, anxiety symptoms, or drinking tendencies may result in limited treatment effectiveness. Equally important, it is necessary to develop helpful treatments that can be tailored to an individual’s mental health needs and to rigorously evaluate these treatments for proven effectiveness using evidence-based methods.
Author affiliations: Department of Social Work and Social Administration, University of Hong Kong, Hong Kong, China (Kee-Lee Chou); and Departments of Community Health Sciences, Psychiatry, and Family Social Sciences, University of Manitoba, Winnipeg, Manitoba, Canada (Tracie O. Afifi).
The National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) was conducted and funded by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), with supplemental support from the National Institute on Drug Abuse.
The authors thank the NIAAA and the US Census Bureau field representatives who administrated the NESARC interviews and made the results available.
Dr. Kee-Lee Chou had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Conflict of interest: none declared.
|AUDADIS-IV||Alcohol Use Disorder and Associated Disabilities Interview Schedule—DSM-IV Version|
|DSM-IV||Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition|
|NESARC||National Epidemiologic Survey on Alcohol and Related Conditions|
|PTSD||posttraumatic stress disorder|
|SF-12||Short Form 12 Health Survey—Version 2|