Key elements of addiction

Addiction is characterized by the compulsion to seek and take a substance, the loss of control in limiting substance intake, and the emergence of a negative emotional state (e.g. dysphoria, anxiety) when substance intake is prevented. Importantly, there are elements of addiction that emerge during the addiction trajectory (e.g. liking, wanting, habit, craving) that are a reflection of key changes in the homeostasis of brain networks that control different behaviours. These homeostatic changes ultimately lead to 1) a decreased sensitivity for natural rewards, 2) an enhanced sensitivity for conditioned substance cues and the expectation of substance use rewards, 3) a weakened control over substance use urges and substance-taking behaviour, and 4) substance tolerance and withdrawal. Significantly, these changes are targets for pharmacological and psychological treatment interventions in addiction.