Gambling is the wagering of something of value (typically money) on an event with some element of chance. It can take many forms, including lotteries, scratch-off tickets, cards, dice, slot machines, racing, animal tracks, sports events, and other games of chance. Gambling may also be conducted with non-money items that have value, such as marbles or collectible game pieces (e.g., Magic: The Gathering and Pogs).

There are a variety of definitions for pathological gambling (PG), which is sometimes described as a “gambling disorder.” For example, people with PG: (0) have difficulty controlling their behavior; (i) lose control over the amount they gamble; (ii) continue to gamble even when they know they are losing; (iii) spend more and more time gambling than other activities; (iv) become depressed or anxious when they win; or (v) commit illegal acts, such as forgery, theft, or embezzlement, in order to fund their gambling. The disorder is a progressive and chronic illness. People with PG often begin to exhibit symptoms in adolescence or young adulthood and develop the disorder over several years.

Although it was once thought that only the most serious gambling problems meet the criteria for a diagnosis of PG, the American Psychiatric Association now recognizes this condition as an impulse control disorder (like kleptomania and pyromania). It is therefore placed in the same chapter of the Diagnostic and Statistical Manual of Mental Disorders as other disorders of impulse control, such as trichotillomania and pyromania.