Theory notes obsessive focus lost when brain chemistry is altered

Susan Brink
Los Angeles Times

Love's first rush is a private madness between two people, all-consuming and endlessly wonderful.

Couples think about the other obsessively – on a roller coaster of euphoria when together, longing when apart.

"It's temporary insanity," says Helen Fisher, an evolutionary anthropologist at Rutgers University in New Jersey.

Now, from her studies of the brains of lovers in the throes of the initial tumble, Fisher has developed a controversial theory. She and her collaborator, psychiatrist J. Anderson Thomson of the University of Virginia, believe Prozac, Zoloft, Paxil and other antidepressants alter brain chemistry so as to blunt the intense cutting edge of new love.

Fisher and Thomson, who describe their theory in a chapter in the book, Evolutionary Cognitive Neuroscience, aren't talking just about the notorious ability of the drugs to dampen sexual desire and performance, although that, they believe, plays its part. They think the drugs also sap the craving for a mate, perhaps even the brain's very ability to fall in love.

That would be bad news, given the widespread use of antidepressants.

Although they lack solid evidence that more people are having trouble falling in love, the scientists cite animal and laboratory science along with some human studies.

For one thing, there's brain chemistry. The chemicals involved in the heart-pounding fall over the cliff into another's life, including dopamine, norepinephrine and serotonin, are the very chemicals altered by many antidepressants.

Fisher cites animal studies showing, for example, that female prairie voles, naturally loyal to one mate, lose interest in him when dopamine is suppressed. Human romantic love is associated with increased activity in dopamine pathways. Antidepressants suppress that activity and are known to curb obsessive thinking. For these reasons, Fisher suggests antidepressants could jeopardize intense romantic love.

There are few studies on the effects of antidepressants on aspects of love beyond libido and sexual performance. But in an intriguing experiment, Canadian psychologist Maryanne Fisher (no relation to Helen) reported evidence in a small 2004 study of what she termed "courtship blunting" in women taking antidepressants.

Asked to rate the attractiveness of men's faces, women taking the drugs rated the men more negatively and breezed through the pictures faster than women not on antidepressants.

There is also anecdotal evidence, which Thompson collects. Although such stories may be anathema to hard science, they can provide the basis for research questions.

A 20-year-old man, who began taking antidepressants when he was 15 and stopped when he was 18, was reluctant to take them again, despite feeling depressed. "No one told him about the sexual side effects. In retrospect, he realized he had the sexual side effects and that might have contributed to his not dating," Thomson says.

Any drug that has sexual side effects, Thomson says, could well blunt other chemicals the brain uses to intently focus on one person or to work up the obsession necessary to fall in love in the first place.

Then there was the 42-year-old single woman who had not been on a date in the eight years she had been taking an antidepressant. "She had not felt any desire (to date) for at least that period of time," he says.

Fisher's and Thomson's theory is new enough that many therapists say they've never heard it discussed. And those who have are cautious. Mental health experts fear that, with recent publicity about suicidal risks in adolescents taking antidepressants, people whose lives could be improved or even saved with medications won't take them.

Some scientists dismiss Fisher's and Thomson's theory. ``Antidepressants tend to tone down the emotions. But they don't interfere with the ability to fall in love. No," says Otto Kernberg, director of the Personality Disorders Institute at the New York Presbyterian Hospital and author of six books on love.

But Richard Tuch, a psychoanalyst at the New Center for Psychoanalysis in Los Angeles, says the theory is challenging. "I think it's a call to the psychiatric community to study this. She's raised the question. Now it's our responsibility to look into it."