Trends in Gambling Research: How Many People Have a Gambling Problem?
Is the rate of problem gambling increasing, declining or stable? Prevalence surveys in Michigan and New Zealand might indicate a shift in the rates of problem gambling. Surveys conducted in Michigan in 1997, 1999 and 2001 were commissioned in response to concerns that the advent of casino gambling in Detroit in 1999 would stimulate an increase in problem gambling. However, "A Survey of Gambling Behaviors in Michigan, 2001"1 found that the 2001 estimates of the rates of past year "problem" gambling and "probable pathological" gambling (a combined estimate of 3.2 percent) "are statistically indistinguishable from those obtained in 1999 and 1997" (Gullickson & Hartmann, 2001, 6).
The New Zealand Gambling Survey conducted follow-up interviews with 143 people who originally participated in the 1991 national survey.2 Since 1991, New Zealand has experienced significant growth in gambling availability through the introduction of new casinos and gaming machines. According to the investigators, "the most notable finding of this study was the large reduction in gambling involvement and gambling-related problems that was evident for participants who were classified as currentprobable pathological and pathological gamblers in 1991" (Abbott, Williams & Volberg, 1999, 7). Most intriguing was the observation that the reduction in problem gambling "contradicts the conventional clinical conceptualization of pathological gambling as a chronic, lifelong disorder" (Abbott et al. 1999, 7).
These findings fly in the face of conventional wisdom, which assumes that the expansion of legalized gambling necessarily leads to an increased rate of gambling disorders. If problem gambling rates are declining or stabilizing, it could be the result of people adapting to the novelty of new gaming opportunities (Shaffer & Hall, 2001). In their study of casino employees, Howard Shaffer and colleagues hypothesized that a segment of this population-exposed to gambling on a daily basis-seemed to adapt to the presence of gambling by regulating their behavior (Shaffer & Hall, in press). Perhaps the keen awareness of the downside of gambling is the reason that a portion of those classified as level 2 or problem gamblers among the employees are able to move back toward health rather than slide into a full-blown gambling disorder.
On the other hand, the findings of the New Zealand and Michigan surveys must be interpreted cautiously. The authors of the New Zealand study warn the reader to remember the small size of the sample when seeking to generalize these findings to all problem and pathological gamblers. The Michigan investigators expressed similar reservations about their sample: "The stability of statewide problem estimates after the casino openings in Detroit is heartening, but one should also recall that the rates in Detroit itself were quite high and not comparably measured in the previous surveys" (Gullickson et al., 2001, 18).
Perhaps the most important message of these surveys is that prevalence studies, although an important tool for scientists, clinicians and public policy-makers, cannot always answer the perennial question: What are the long-term effects of expanded gambling opportunities on a population? Even when replicated over a period of time, prevalence studies provide only a snapshot of the disorder at a particular time. Alternatively, prospective longitudinal research in the form of incidence studies can illuminate the long-term effects of gambling. Although more than 200 prevalence studies related to gambling have been conducted since the 1970s, there are no incidence studies examining this phenomenon. For example, an incidence study that follows a population for five years would be able to discern what percentage of the population develops its first episode of gambling disorder. Unfortunately, the high cost of longitudinal studies compared with one-time prevalence surveys is a major reason for the dearth of such investigations.
Future research priorities should include not only longitudinal studies but also more focus on vulnerable or high risk sub-populations such as older adults, casino employees and people with lower socio-economic status. The current research agenda of the Institute for Research on Pathological Gambling and Related Disorders at Harvard Medical School's Division on Addiction reflects these concerns. For example, Shaffer and Matthew Hall have continued their work on casino employees and their next publication from this project, "Longitudinal patterns of gambling and drinking problems among casino employees," provides a longitudinal examination of gambling problems; this study is in press at the Journal of Social Psychology. In addition, their study of gambling disorders among a sample of homeless, substance-abusing treatment seekers is due to be published in Psychiatric Services. Finally, the Institute's extramural grants program, open to non-Harvard University applicants, recently selected for funding a project on gambling disorders among the elderly.
1The study is available from the Web site of the Evaluation Center at Western Michigan University:www.wmich.edu/evalctr/pubs.html.
2The New Zealand Gaming Survey is available from the following Web site: www.dia.govt.nz/diawebsite.nsf.
REFERENCES
Gullickson, A. R. & Hartmann, D. (2001). A Survey of Gambling Behaviors in Michigan, 2001. Kalamazoo, Mich.: The Evaluation Center in Conjunction with the Kercher Center for Social Research, Western Michigan University.
Shaffer, H. J., Freed, C. R., & Healea, D. (in press). Gambling Disorders Among a Cohort of Homeless Substance Abusing Treatment Seekers. Psychiatric Services.
Shaffer, H. J. & Hall, M. N. (in press). Longitudinal patterns of gambling and drinking problems among casino employees. Journal of Social Psychology.
Shaffer, H. J. & Hall, M. N. (2001). Updating and refining meta-analytic prevalence estimates of disordered gambling behavior in the United States and Canada. Canadian Journal of Public Health, 92(3), 168-172.
Shaffer, H. J., Vander Bilt, J., & Hall, M. N. (1999). Gambling, drinking, smoking and other health risk activities among casino employees. American Journal of Industrial Medicine, 36(3), 365-378.
Shaffer, H. J. & Korn, D. A. (2002). Gambling and related mental disorders: a public health analysis, Annual Review of Public Health (Vol. 23, pp. 171-212). Palo Alto, Calif.: Annual Reviews, Inc.
