Gambling is a worldwide activity in which people wager money or something of value. It includes games of chance that involve a random outcome, and skill-based activities in which the player may improve his or her chances of winning, such as playing poker or betting on horse races. Some people gamble for pleasure, while others do so to alleviate unpleasant feelings or to socialize.

Problem gambling can have serious personal, family and financial consequences. In addition, it is associated with a variety of mental health problems, including depression, anxiety, alcohol misuse and suicidal ideation. The understanding of the adverse effects of gambling has undergone a radical change in recent years. Individuals who experience gambling-related problems are now considered to have psychological or emotional disorders, similar to the way that alcoholics are viewed in the past.

Gambling can occur in many forms, from a casual game of cards with friends to organized lotteries and sports betting. It is estimated that the total amount of money legally wagered worldwide annually is over $10 trillion. Several factors have been identified that contribute to the development of gambling addiction, including impulsivity and sensation- and novelty-seeking. Differences in brain regions involved in impulse control and risk-taking have also been linked with a tendency to gamble. These differences may be due to genetics or the environment in which a person is raised. In addition, certain cultures have a central role in the values that are considered acceptable and unacceptable for gambling behavior.