Two medicines usually given to people who are addicted to opioid drugs also help with compulsive gambling. The finding suggests there may be similar brain circuits involved in behavioural addictions as those that cause drug addiction.

Addiction is usually thought of in the context of people who can’t stop drinking alcohol or who take drugs. A large group of these drugs are those that act through opioid receptors in the brain, such as heroin or fentanyl. This causes the release…