Gambling involves wagering something of value, such as money or material valuables, on an event that is determined by chance. Historically, gambling was often considered immoral and illegal and was the basis for criminal activities such as the mafia. During the 20th century, however, attitudes changed and laws against gambling were relaxed. Today, millions of people gamble for both fun and profit.

The world’s legal gambling industry is a multibillion dollar business. Hundreds of thousands of people work in gambling businesses as dealers, odds compilers, and marketing staff, among others. The amount of money legally wagered on sports games such as football is enormous and is largely done through state-organized lotteries or organized gambling.

Some people gamble for entertainment and enjoy it, but some become addicted to gambling. Problem gambling causes many serious harms to the individual, his or her family, and society, and is the leading cause of financial disaster and bankruptcy in the United States. Problematic gambling affects the brain by hijacking its learning mechanism through random rewards. It also increases the production of dopamine, a neurotransmitter that makes us feel excited and happy. When we experience a positive outcome in gambling, the dopamine reward system encourages us to repeat the activity and try again.

There is a growing role for the evaluation of patients’ gambling behaviors in primary care settings. This article reviews the rationale for viewing pathological gambling as an addictive disorder and discusses strategies for screening for and treatment of problem and pathological gambling.