Rock On, Sweet Dopamine
Take dopamine. Elevated levels of dopamine in the brain produce extremely focussed attention,2 as well as unwavering motivation and goal-directed behaviors.3 These are central characteristics of romantic love. Lovers intensely focus on the beloved, often to the exclusion of all around them. Indeed, they concentrate so relentlessly on the positive qualities of the adored one that they easily overlook his or her negative traits;4 they even dote on specific events and objects shared with this sweetheart. Besotted lovers also regard the beloved as novel and unique. And dopamine has been associated with learning about novel stimuli.5 Central to romantic love is the lover’s preference for the beloved. As you recall from chapter two, among prairie voles, this favoritism is associated with heightened levels of dopamine in specific brain regions. And it is not a leap of logic to suggest that if dopamine is associated with mate preference in prairie voles, it can play a role in partiality in people. As you recall, all mammals have basically the same brain machinery, although size, shape, and placement of brain parts definitely vary.6 Ecstasy is another outstanding trait of lovers. This, too, appears to be associated with dopamine. Elevated concentrations of dopamine in the brain produce exhilaration, as well as many of the other feelings that lovers report—including increased energy, hyperactivity, sleeplessness, loss of appetite, trembling, a pounding heart, accelerated breathing, and sometimes mania, anxiety, or fear.7 Dopamine involvement may even explain why love-stricken men and women become so dependent on their romantic relationship and why they crave emotional union with their beloved. Dependency and craving are symptoms of addiction—and all of the major addictions are associated with elevated levels of dopamine.8 Is romantic love an addiction? Yes; I think it is—a blissful dependency when one’s love is returned, a painful, sorrowful, and often destructive craving when one’s love is spurned. In fact, dopamine may fuel the frantic effort a lover musters when he/she feels the love affair is in jeopardy. When a reward is delayed, dopamine-producing cells in the brain increase their work, pumping out more of this natural stimulant to energize the brain, focus attention, and drive the pursuer to strive even harder to acquire a reward: in this case, winning one’s sweetheart.9 Dopamine, thy name is persistence. Even the craving for sex with the beloved may be indirectly related to elevated levels of dopamine. As dopamine increases in the brain, it often drives up levels of testosterone, the hormone of sexual desire. Norepinephrine’s High Norepinephrine, a chemical derived from dopamine, may also contribute to the lover’s high. The effects of norepinephrine are varied, depending on the part of the brain it activates. Nevertheless, increasing levels of this stimulant generally produce exhilaration, excessive energy, sleeplessness, and loss of appetite—some of the basic characteristics of romantic love. Increasing levels of norepinephrine could also help explain why the lover can remember the smallest details of the beloved’s actions and cherished moments spent together. This liquor is associated with increased memory for new stimuli.10 A third chemical may also be involved in that “irresistible” feeling of magic Homer spoke of: serotonin. Serotonin A striking symptom of romantic love is incessant thinking about the beloved. Lovers cannot turn off their racing thoughts. Indeed, this single aspect of being in love is so intense that I use it as the litmus test of romantic passion. The first thing I ask anyone who tells me they are “in love” is, “What percentage of your waking hours do you think about your sweetheart?” Many say “over 90 percent.” Some bashfully admit they never stop thinking about “him” or “her.” Lovers are obsessed. And doctors who treat individuals with most forms of obsessive-compulsive disorder prescribe SSRIs (selective serotonin reuptake inhibitors) such as Prozac or Zoloft, substances that elevate levels of serotonin in the brain.11 So I came to suspect that the lover’s persistent, involuntary, irresistible ruminations about a sweetheart might be associated with low levels of some type (there are at least fourteen variations) of this chemical compound.12 There is some support for my reasoning. In 1999, scientists in Italy studied sixty individuals: twenty were men and women who had fallen in love in the previous six months; twenty others suffered from unmedicated obsessive-compulsive disorder (OCD); twenty more were normal, healthy individuals who were not in love and were used as controls. Both the in-love participants and those suffering from OCD were found to have significantly lower levels of serotonin than did the controls.13 These scientists examined serotonin levels in components of the blood, however, rather than the brain. Until scientists document the activity of serotonin in specific brain regions, we cannot be sure of the role of serotonin in romantic love. Nevertheless, this experiment has established, for the first time, a possible connection between romantic love and low levels of bodily serotonin. All those countless hours when your mind races like a mouse upon a treadmill may be associated with reduced levels of serotonin coursing through the highways of the brain. And as a love affair intensifies, this irresistible, obsessive thinking can increase—due to a negative relationship between serotonin and its relatives, dopamine and norepinephrine. As levels of dopamine and norepinephrine climb, they can cause serotonin levels to plummet.14 This could explain why a lover’s increasing romantic ecstasy actually intensifies the compulsion to daydream, fantasize, muse, ponder, obsess about a romantic partner."