Timeline of a Love Affair
This Is Your Brain on Love
Researchers have looked for changes in the brain that may go along with the state of limerence. Studies show that the brain chemicals dopamine and serotonin may be related to the peculiar feelings and behavior of people in love.
Dopamine is a feel-good brain chemical. When the brain is flooded with dopamine, we feel various degrees of well-being, from contentment to euphoria. High dopamine levels may be related to the "high" people experience early in a love affair. People in love also tend to notice less need for sleep, extra energy, and decreased appetite. Some scientists think it's no coincidence that these are also common effects of amphetamines and cocaine, which alter the mind mainly by raising dopamine levels.
The downside of high dopamine is anxiety, restlessness, and emotional volatility. Such bad feelings are often mixed up with good ones in passionate love affairs. Dopamine plays a role in our ability to concentrate and control our thoughts, so elevated dopamine levels could explain lovers' tendency to focus exclusively on their beloved.
Because low serotonin in the brain is related to obsessive disorder, some scientists think low serotonin is a likely explanation for the way people in love obsess about their beloved.
Falling in love has been linked to hormonal changes, too. Researchers in Italy who studied serotonin and love affairs compared hormone levels of people recently fallen in love and those who were single or in a long-lasting relationship. They found that women who had recently fallen in love had higher testosterone levels than those who had not recently fallen in love, and men in love had lower testosterone than those who had not. Both men and women who had recently fallen in love also had higher levels of the stress hormone cortisol. When researchers tested these people again one to two years later, their hormone levels were no longer different.
The "in-love" stage of a love affair typically lasts six to 18 months, and occasionally as long as three years, says Denise Bartell, PhD, psychologist at the University of Wisconsin, Green Bay. But it does wane at some point. People get used to loving each other, maybe in the same way that people develop tolerance to the effects of mind-altering drugs.