DOD established the Defense Health Agency on October 1, 2013, to provide administrative support for the services’ respective medical programs, combine common “shared” services, and coordinate the work of the services’ military treatment facilities with care purchased from the private sector. The Defense Health Agency supports the delivery of services to Military Health System beneficiaries and is responsible for integrating clinical and business processes across the Military Health System. The Military Health System, which serves all of the military services including the Coast Guard, has two missions: (1) supporting wartime and other deployments and (2) providing peacetime health care. The Military Health System is a complex organization that provides health services to almost 10 million DOD and Coast Guard servicemembers and their dependents across a range of care venues, including the battlefield, traditional hospitals and clinics at stationary locations, and authorized civilian providers. The Military Health System employs more than 150,000 military, civilian, and contract personnel working in military treatment facilities. In the Military Health System, care is provided through TRICARE, DOD’s regionally structured health-care system. Under TRICARE, DOD and Coast Guard active-duty servicemembers typically receive most of their care in what is known as the direct-care component—that is, in military hospitals and clinics referred to as military treatment facilities. The care provided in military treatment facilities is supplemented by services offered through TRICARE’s purchased-care networks of civilian providers. The Defense Health Agency oversees the TRICARE health plan and military treatment facilities and subordinate clinics, but does not have direct command and control of the military services’ military treatment facilities outside of the National Capital Region. Each military service, including the Coast Guard, operates its own military treatment facilities and their subordinate clinics. In addition, the military services, including the Coast Guard, administer medical programs and provide medical and mental-health services to servicemembers. Military medical personnel providing mental-health services include psychiatrists, psychologists, mental-health nurse practitioners, licensed social workers, and alcohol and drug counselors. Although it is part of the Military Health System, the Coast Guard has adopted some, but not all, of DOD’s health-related guidance. According to DOD officials, the Navy, the Marine Corps, and the Air Force provide nonmedical education and counseling services for individuals with problem gambling who do not meet the criteria for gambling disorder diagnosis. These educational and supportive services are provided through the Fleet and Family Service Centers, the Marine Corps Community Services Behavioral Health Clinics, and the Airman and Family Readiness Centers, respectively, as well as through the Military OneSource program—a program that provides confidential, short-term, nonmedical counseling services and information both face-to-face and remotely. Coast Guard servicemembers can receive counseling services through CG SUPRT, a confidential program similar to Military OneSource. Army officials told us that gambling disorder is not currently addressed within the Army Substance Abuse Program and that Army regulation does not require the program to cover gambling disorder. In addition, service chaplains offer nonmedical counseling services for DOD and Coast Guard servicemembers. DOD officials stated that individuals with a diagnosable gambling disorder would be referred to a military treatment facility. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, defines gambling disorder as the “persistent and recurrent problematic gambling behavior leading to clinically significant impairment or distress.” The term gambling disorder replaced pathological gambling as the gambling-related diagnosis in the most recent (2013) edition of the Diagnostic and Statistical Manual of Mental Disorders. The primary difference between the two diagnostic terms is that pathological gambling was considered an impulse-control disorder whereas gambling disorder is in the diagnostic category of substance-related and addictive disorders. Table 1 presents the diagnostic criteria in the fourth and fifth editions of the Diagnostic and Statistical Manual of Mental Disorders. In addition, the American Society of Addiction Medicine published criteria that evaluate the appropriate venue for an individual to be treated based on a multidimensional assessment and that are designed to define one national set of criteria for providing outcome-oriented and results-based care in the treatment of addiction. According to the American Society of Addiction Medicine, addiction—which it defines as “pathologically pursuing reward and/or relief by substance use and other behaviors”— can be associated with various substances and behaviors, such as alcohol and gambling. In explaining its decision to recategorize gambling disorder as an addiction in the 2013 revision of the Diagnostic and Statistical Manual of Mental Disorders, the American Psychiatric Association observed that gambling disorder and substance-related disorders display commonalities in symptoms as well as treatment. In addition, the Diagnostic and Statistical Manual of Mental Disorders states that individuals with gambling disorder have high rates of other mental disorders, such as substance-use disorders, depressive disorders, anxiety disorders, and personality disorders. Table 2 presents the similarities and differences between substance use and gambling disorder. Based on DOD data that show 514 DOD and Coast Guard active-duty servicemembers and 72 Reserve Component servicemembers—less than 0.03 percent of the average number of servicemembers in each year—were diagnosed with gambling disorder or seen for problem gambling in fiscal years 2011 through 2015, DOD officials stated that the prevalence of gambling disorder in the military is low. DOD bases its determination of prevalence of gambling disorder and problem gambling on Military Health System data and does not include other sources of information, such as DOD-wide surveys and records of treatment provided outside of the Military Health System. The active-duty components of the DOD military services and the Coast Guard averaged about 1.4 million servicemembers each year, and the Reserve Component averaged about 0.8 million servicemembers each year. Table 3 shows the number of DOD and Coast Guard servicemembers who were seen through the Military Health System for pathological gambling, gambling disorder, and problem gambling during fiscal years 2011 through 2015. The Defense Health Agency compiles these problem gambling and gambling disorder data in the Military Health System Data Repository, which includes data on clinical interactions between DOD and Coast Guard servicemembers and health-care professionals in military treatment facilities and in civilian facilities through the TRICARE system, and DOD health officials told us that they use these data to determine the prevalence of gambling disorder. The prevalence of alcohol-related disorders is higher by comparison, according to data from the Military Health System Data Repository. For example, in fiscal years 2011 through 2015, 107,702 DOD and Coast Guard active-duty servicemembers and 10,896 Reserve Component servicemembers were seen through the Military Health System for alcohol-related disorders. The Military Health System Data Repository does not include data on DOD and Coast Guard servicemembers who received treatment or counseling for gambling disorder or problem gambling outside of the Military Health System. For example, Marine Corps officials stated that Marines may receive short-term, nonmedical counseling at Marine Corps Community Services Behavioral Health Substance Abuse Counseling Centers, and these interactions will be reflected in the Military Health System Data Repository only when the patient also visits a military treatment facility for this issue. Additionally, the Military Health System Data Repository does not capture data regarding treatment received by servicemembers of the Reserve Component unless they are on active orders for more than 30 days, need treatment for a line-of-duty injury or condition, or enrolled in TRICARE Reserve Select. According to DOD officials, Reserve Component medical personnel also are unlikely to learn about an individual’s gambling problem because of the short periods that nonactivated members of the Reserve Component spend in uniform, which limits the ability of the medical personnel to refer them for treatment and counseling. DOD officials also told us that servicemembers who call Military OneSource—a telephonic resource for servicemembers—for referrals for gambling problems may be referred to a military treatment facility or a TRICARE provider, but they also may be referred to local, civilian treatment programs or support groups. For example, servicemembers may seek treatment through state programs or from a nearby Gamblers Anonymous chapter. DOD officials told us that they do not collect data on the number of servicemembers who call Military OneSource for problem gambling or gambling disorder, nor do they collect data on gambling-related referrals. DOD surveys of servicemembers, data on medical care provided by the Department of Veterans Affairs, and reviews of literature provide contextual information on the prevalence of problem gambling and gambling disorder in the military, but these data are not directly comparable to DOD clinical data. DOD’s 2002 Health Related Behaviors Survey of the DOD active-duty population and the 2010–2011 survey of the DOD Reserve Component populations asked respondents about their problematic gambling behaviors, but the results of these surveys are not directly comparable to the DOD data, as shown in table 3. An estimated 1.2 percent (with a standard error of 0.2 percent) of active-duty military personnel met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for lifetime prevalence of probable pathological gambling based on the self-administered survey of health-related behaviors. Similarly, an estimated 1.3 percent (with a standard error of 0.1 percent) of Reserve Component respondents to the 2010–2011 DOD Health Related Behaviors Reserve Component Survey met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for lifetime prevalence of probable pathological gambling. These survey data are not comparable to DOD data presented in table 3 for three reasons. First, the surveys were based on the Diagnostic and Statistical Manual of Mental Disorders criteria that were applicable at the time of the surveys, which, as discussed above, differed from the current version in the disorder’s categorization and the number of diagnostic criteria.