So look at three key components of love, involving different but connected brain systems:

• Lust — driven by androgens and estrogens, the craving for sexual gratification
• Attraction — driven by high dopamine and norepinephrine levels and low serotonin, romantic or passionate love, characterized by euphoria when things are going well, terrible mood swings when they’re not, focused attention, obsessive thinking, and intense craving for the individual
• Attachment — driven by the hormones oxytocin and vasopressin, the sense of calm, peace, and stability one feels with a long-term partner