Medication-overuse headache (MOH) is a clinically important entity and it is now well documented that the regular use of acute symptomatic medication by people with migraine or tension-type headache increases the risk of aggravation of the primary headache. MOH is one the most common causes of chronic migraine-like syndrome. In this article, we analyse the possible mechanisms that underlie sensitization in MOH by comparing these mechanisms with those reported for other forms of drug addiction. Moreover, the evidence for cognitive impulsivity in drug overuse in headache and in other forms of addiction associated with dysfunction of the frontostriatal system will be discussed. An integrative hypothesis for compulsive reward-seeking in MOH will be presented.