The Love Drug
When a couple has chemistry, they usually have it both figuratively and literally. Behind those sweaty palms, thumping heart, stomach in knots, and nervous jitters is the physiology of love. Such sensations often mark the first stage of a romantic relationship, called limerence.
However, post-honeymoon period (anywhere from eighteen months to four years), our chemistry transforms the physical manifestation of love into a different form. In stable, long-term relationships that have reached the secure attachment phase, many people experience a warm, comfortable feeling of security. Attachment love hormones are more comparable to morphine than the cocaine-like high of limerence.
Phenylethylamine and Dopamine
The brain's best known love chemical is phenylethylamine, or PEA. It is a naturally occurring amphetamine. Indeed, "love is a drug," says Helen Fisher, an anthropologist at Rutgers University and author of Anatomy of Love. According to Dr. Fisher, "the ventral tegmental area is a clump of cells that makes dopamine, a natural stimulant, and sends it out to many brain religions when one is in love. This is the same region affected when you feel the rush of cocaine." Phenylethylamine produces the neurochemical dopamine, and contributes to the pleasurable, on-top-of-the-world feeling that attraction brings. (Source: CBSnews.com) Note: Non-romantic activities that stimulate PEA production are skydiving and eating chocolate.
Tolerance for the Love Drug
Many scientists believe that after a limerence, typically anywhere from 18 months to 4 years, your body becomes accustomed to those energizing love drugs. Just like you build a tolerance to alcohol, your limbic system adapts to the formerly cocaine-like neurochemical state. In this secure phase of the relationship, your brain produces endorphins, opiates more like morphine than speed. "Unlike PEA, [these endorphins] calm the mind, kill pain, and reduce anxiety," Dr. Fisher explains.