The early stages of love are governed by parts of the brain that are used for goal-seeking and reward, and resembles obsessive-compulsive disorder:
The early stages of a romantic relationship spark activity in dopamine-rich brain regions associated with motivation and reward. The more intense the relationship is, the greater the activity.
The regions associated with emotion, such as the insular cortex and parts of the anterior cingulate cortex, are not activated until the more mature phases of a relationship.
