The Biology and Treatment of Gambling Disorder

Introduction

Gambling has become increasingly accessible and socially acceptable over the past two decades, with an increasing number of venues and opportunities through casinos, video lottery terminals, sports betting venues, and online poker and other gambling sites. Although most people participate in gambling activities recreationally, some experience gambling problems, including the most severe form, gambling disorder. Gambling disorder has been associated with significant financial debt, family tension, divorce, and criminal activity such as fraud and embezzlement. Extreme cases have involved staged kidnappings and serious child neglect leading to death, murder, and suicide.

Gambling disorder is defined as persistent and recurrent maladaptive gambling behavior that jeopardizes personal, occupational, or social functioning. In the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), gambling disorder is classified as the first non–substance-based disorder in a new addiction category.

The Psychiatric Nosology of Gambling Disorder

Gambling disorder has been conceptualized as a disorder falling within an obsessive-compulsive spectrum and as a “behavioral addiction.” Studies of impulse control disorders describe clinical elements including an urge to engage in a typically enjoyable yet, in the long term, counterproductive or harmful behavior, a mounting tension until the behavior is completed, a temporary abatement of tension following completion of the behavior, and a return of tension or appetitive urge following varying amounts of time. Impulse control disorders have been described as having elements of impulsivity and compulsivity. Although the underlying motive of gambling disorder is initially pleasure, with increasing frequency individuals may feel out of control and their urges may become unpleasant or ego-dystonic. Although some compulsive aspects to gambling are evident, the co-occurrence of obsessive compulsive disorder and gambling disorder is not that common, while comorbidity with substance dependence occurs frequently. The diagnostic criteria of gambling disorder, listed in the DSM-5, share similarities with those for substance dependence. Individuals with gambling disorder can demonstrate tolerance and withdrawal symptoms as they gamble with increasing amounts of money in order to achieve the same hedonic experience, and they may become irritable or restless when attempting to cut down or quit their gambling. Like individuals with drug addictions, those with gambling disorder demonstrate impaired control over their behavior and may hide the extent of their involvement from loved ones or commit forgery or fraud to sustain their gambling. The term problem gambling has been at times used to describe less severe patterns of gambling than exhibited in gambling disorder. This category is conceptually similar to that of substance abuse, although no formal criteria exist for problem gambling. In addition, the term has been used at times inclusive and at other times exclusive of gambling disorder. The most commonly used screening instrument for gambling disorder is the South Oaks Gambling Screen, and this screen queries the types and frequencies of gambling behaviors as well as gambling-related impact on life functioning, particularly with respect to borrowing money for gambling. The South Oaks Gambling Screen is valid and reliable, and a score ≥5 signifies probable gambling disorder.

Cognitive Distortions

A frequently acknowledged criterion of gambling disorder is the “chasing” of losses, whereby gamblers attempt to regain accumulated losses by returning to a gambling venue shortly following sustaining gambling losses. Nearly winning (e.g., receiving identical symbols on 2 of the 3 reels on an electronic gambling machine) has been suggested to contribute to gambling behaviors. Individuals with gambling disorder, as well as recre-ational gamblers, may report other cognitive distortions, such as overestimating their chances of winning and their sense of control: “I know what it takes to win this game.” In dice gambling and certain other forms, individuals may keep track of previous numbers in order to inform their subsequent bets with the thought that certain numbers will either appear more frequently because they have been observed previously (“hot numbers”) or not (“numbers that are due”). Such a gambler’s fallacy ignores laws of probability: that each role of the dice functions independently of the last. Superstitious behaviors (“I only play at nights”) and attributional biases (“That dealer always makes me lose”) are also expressed in gambling disorder as well as in recreational gambling groups. Cognitive distortions may represent relevant considerations in the maintenance of gambling disorder, although their frequent occurrence in nonpathological gambling samples questions their centrality to the disorder.

Prevalence Estimates and Characteristics

Precise gambling disorder prevalence estimates may be related to assessment measures and other factors. However, most studies report lifetime prevalence estimates ranging from 0.4% to 3% in the general population, representing approximately 2 to 3 million adults in the United States. All types of gambling are also not equally represented in gambling disorder populations; one study suggests that pull-tabs, casino gambling, bingo, cards, lottery and sports betting, in descending order, are most strongly associated with gambling disorder, and another study found the highest proportion of pathological gamblers at off-track compared with other venues. Pathological gamblers may engage in multiple types of gambling. Factors associated with gambling disorder include male sex, adolescent and young adult age, and presence of other psychiatric disorder(s). In addition, minorities and persons with a lower socioeconomic status also appear more likely to gamble and may be at particular risk for gambling disorder. Some studies have found that men and women with gambling disorder show similarities in demographic and clinical features, including time spent gambling, percentage of income lost through gambling, and gambling urge severity. Other studies have identified gender differences in manifestations of gambling behaviors that may have significant implications for prevention and treatment strategies. Although men constitute about two-thirds of the gambling disorder population and often show a longer duration of onset and begin gambling early in life (childhood/adolescence), women appear more likely to develop gambling disorder later in life and demonstrate a more rapid progression between onset and problematic engagement, a phenomenon observed in substance use behaviors and described as “telescoping.” Gender differences also exist in the types of gambling behavior and in gambling triggers. Women may report engaging in fewer forms of gambling, mostly bingo and slot machines, and often cite feeling prompted by negative mood states. In contrast, men are more likely to gamble on cards or sporting events and report a greater saliency of sensory cues, such as sounds or advertisement, in their triggers for gambling. In addition, women, as compared with men with gambling problems, may experience greater psychiatric comorbidity, particularly with mood and anxiety disorders.

Gambling disorder frequently co-occurs with other psychiatric disorders. Some studies estimate that up to three-fourths of individuals with gambling disorder report an alcohol use disorder, over 60% are daily tobacco smokers or nicotine dependent, and up to 40% report other drug abuse. About half of individuals diagnosed with gambling disorder also experience a mood disorder, with a particularly high odds ratio of 8.6 for mania, and roughly 40% are also diagnosed with anxiety disorders.

Estimates of personality disorders range from 29% to 93% in the gambling disorder population, with one study reporting an average of 4.6 personality disorders per person with gambling disorder. Although borderline, histrionic, and antisocial personality disorders are most often cited, these may represent a component of an externalizing syndrome. Personality and temperamental factors may play a role in the maintenance of gambling disorder, as pathological gamblers may show high levels of impulsiveness, novelty-seeking, rigidness, extravagance, and harm avoidance combined with low levels of self-directedness. In particular, impulsivity has been investigated as a key underlying construct, and accordingly, in gambling disorder, severity of gambling behavior and psychological disturbances appear related to this measure. Identification of co-occurring disorders is important as the disorders may guide treatment strategies and influence treatment outcome.

The Biochemistry of Gambling Disorder