Addictive behavior (e.g. drug addiction) is characterized by compulsions to seek and take a drug, loss of control in limiting intake, and emergence of a negative emotional state (e.g., dysphoria, anxiety, irritability) reflecting a motivational withdrawal syndrome when access to the drug is prevented. Drug addiction has been conceptualized as a disorder that involves elements of both impulsivity and compulsivity (Koob & Le Moal, 1997). According to this view, addictive behavior is a result of cycles of impulsivity and compulsivity that are comprised of several stages, and where impulsivity often dominates at the early stages and compulsivity dominates at terminal stages (Figure 1).
Figure 1: Impulsivity-compulsivity cycle leading to addictive behaviour