Gambling involves putting something of value at risk for the chance to win more. It can include games of pure chance, such as lottery and scratch-off tickets, as well as those that involve skill, such as card games, sports betting, and horse racing (Bruce and Johnson, 1996). Skill in these activities may reduce the chances of a negative outcome but the ultimate outcome remains uncertain (i.e., a winning hand of poker or a horse with the best jockey).

There is consensus that gambling requires impulsive behavior and that it can lead to losses. Some research focuses on specific dimensions of impulse control, such as sensation- and novelty-seeking and arousal, which may contribute to the initiation and progression of gambling behavior. Others focus on the relationship between gambling and other disorders, such as dissociation, depression, and underlying mood problems, which can be made worse by compulsive gambling.

There is also an ongoing debate about whether gambling should be categorized as an addiction. Some people have argued that pathological gambling is an addiction and has similar features to other substance abuse disorders, as reflected in the changing nomenclature in the Diagnostic and Statistical Manual of Mental Disorders (DSM; American Psychiatric Association, 1980, 1987, 1994). Others have questioned this, noting that the evidence supporting the view that gambling disorder is an addictive behavior is limited. This is a complex issue, and it is important that researchers, psychiatrists, and other treatment care clinicians agree on terminology to facilitate communication and understanding.