Berit Brogaard has written a book called On Romantic Love: Simple Truths about a Complex Emotion. Brogaard writes:
When you fall in love with someone, norepinephrine fills you with raucous energy, serotonin boosts your self-confidence, and dopamine generates a feeling of pleasure. New love is a kind of love addiction but not yet a kind of pathological love addiction. In falling in love, however, the brain is on crack—a dangerous state of mind.