Although BPD has long been ascribed to problematic parenting, scientists now believe that the borderline personality develops out of a microbiological flaw. Borderlines exhibit a highly reactive limbic system in conjunction with a decreased capacity for cortical control of it, reports Mayo Clinic psychiatrist Brian Palmer. Vulnerability to the disorder appears to be inherited in the form of a tempestuous temperament, although early care taking in some way seems to activate it.
The condition may not manifest until adolescence—often with self-cutting, burning, or frank suicidal behavior—but it begins long before. “As children, they are hard to parent,” says Palmer. In the absence of exceptional parenting, they never achieve self-regulationor a stable sense of self and never learn to tolerate any distress.
“There’s an inner sense of emptiness that can be haunting,” observes Yeomans. Uncertainty about who they are often keeps them from following a clear path in life. “One day I’ll be wearing Lilly Pulitzer and pearls and playing the role of a perfect Southern belle; the next I’ll be dyeing my hair black, wearing tie-dye and hemp necklaces, smoking pot and listening to The Grateful Dead,” writes borderline sufferer Jennifer O’Brien. “I’ve been to three different universities since I started college, and I’ve changed my major 10 times.”
Seeding the emotional storms, says Harvard psychiatrist John Gunderson, director of the Borderline Personality Disorder Center at McLean Hospital, is a hypersensitivity to rejection. Borderlines are quick to assume others are excluding them—and quick to react to that perceived rejection. “Say you’re having dinner with a borderline person and someone else comes into the room, and you start a conversation with that other person,” Gunderson offers. “The borderline is liable to think that the other person is preferred, and to feel betrayed. When the other person leaves, the borderline will say something like, ‘What was so good about her?'” Paranoia, especially arising in interpersonal conflict, has been one of the diagnostic criteria for borderline disorder.
Borderlines’ all-consuming fear of rejection stems from a bone-deep terror that the people they’re close to will abandon them. “My significant other travels to visit his family and conduct business overseas,” Debbie Corso says. “Each time he traveled, I would become a complete and total mess—ending up in the emergency room dehydrated and having not eaten.”
The fear of abandonment commonly drives borderlines to seek confirmation that they truly matter. In practice, it could mean interrupting a boyfriend during an important work meeting or showing up at his doorstep in pajamas in the middle of the night. “I feel I’m going to die if I can’t contact the person,” says “Kim,” a 32-year-old mother from the Northeast who was diagnosed as borderline several years ago. “I don’t care what the consequences might be of my contacting them. I know it isn’t going to end well but I can’t stop.”
Their overwrought rejection sensitivity leads borderlines to assess other people and situations in all-or-nothing terms. “There’s a tendency to operate in extremes—black or white, right or wrong,” says psychiatrist Jerold Kreisman, author of I Hate You—Don’t Leave Me: Understanding the Borderline Personality. “What they’re feeling right now defines things: I have this friend I’ve known for 10 years, but we had this violent disagreement about politics and now I hate his guts.'” In a romantic context, a borderline person might tell her partner, “You’re the most amazing guy I’ve ever met. I want to share my life with you,” and a few hours later gather all his belongings and pile them in the driveway after he “rejects” her by talking to an ex for a few minutes at a party.
Chaos and crises, in fact, bring comfort to borderlines. “They actually feel safer in chaotic environments and relationships,” says San Diego psychiatrist David Reiss. “In a chaotic situation, the person knows the territory. In a calm situation, the person feels insecure, not knowing when the next shoe will drop and unprepared for what type of abuse or disruption may lie ahead.”
Chaos serves another important function for borderlines. It distracts them from their emotional turmoil, observes the Mayo Clinic’s Palmer. Some of the signature behaviors of borderline personality disorder—self-cutting, sexual promiscuity, drug use, bingeing and purging, suicidal gestures—are attempts to escape from the intense negative emotions that overwhelm them. As a result, they often court chaos.
The affirmation that borderlines pursue so desperately from others turns out to be the Achilles’ heel of their lives. Their interpersonal intensity—emotional outbursts, heated middle-of-the-night exchanges—often jeopardizes their most important relationships. Calling a friend at four in the morning after a fight, pleading “I have to see you right now. I have to know that things are OK between us,” is seldom endearing. Says Gunderson: “Borderlines engineer the ending of the very relationships they covet” by wearing out friends and loved ones.
And their behavior is so predictably unpredictable that it can be captured empirically. In a recent study, healthy subjects were partnered with borderline patients in an online game of strategy that required players to cooperate in order to succeed. But the borderline patients so frequently acted erratically and broke alliances that the healthy players stopped collaborating—even though it meant sacrificing potential “earnings.”
“People with borderline personality disorder are characterized by their unstable relationships, and when they play this game, they tend to break cooperation,” says Read Montague, director of the Human Neuroimaging Laboratory at Virginia Tech, who reported the findings in PLoS Computational Biology.
The chaos of everyday life can turn mundane events like completing a work project or submitting a tax return into Sisyphean tasks. “I’ve had a hard time keeping a job my entire life,” reports Corso, who has worked as a preschool teacher, advertising assistant, telephone operator, makeup artist, and cashier, among other things. “When a crisis hit, I’d make a dramatic exit—never realizing that I could slow down, call in sick, and pull myself together. So my career path has been quite a struggle.”
“Less than schizophrenia but ahead of lots of other psychiatric disorders,” says Palmer about the role genes play in the genesis of borderline personality disorder. “The condition is now believed to be 55 percent heritable.” Increasingly, the origins of the condition are seen as a classic interplay of nature and nurture.
The parental role is complex, says Gunderson. Children who develop BPD inherit a temperament—one that makes them highly reactive, emotional, and so hypersensitive to perceived anger or rejection they might cry inconsolably if scolded—that can tax even a good caretaker. “The hostile, conflicted relationships that evolve are not, as traditionally thought, a result of poor parents, but of parents whose parenting is shaped by a difficult child. It might take an extraordinarily calm parent to keep a genetically loaded infant from developing the disorder.”
Researchers have identified unusually heightened activity in the amygdala, a brainstructure that forms part of the limbic system, which governs memory and the sense of smell as well as emotional reactivity. They believe the reactivity gives rise to a hair-trigger temper. In addition, many borderline patients have a specific short variant of the serotonin transporter, or 5-HTT, gene. It affects how much neurotransmitter is available to nerve cells, and the short allele has been linked to anxious, aggressive, and impulsive behavior.
But abusive parenting and other traumatic childhood experiences still seem to figure into the disorder. A large number of sufferers do, in fact, have incidents of physical or emotional abuse in their past, although in some cases they may be the result of a difficult-to-manage temperament, not its cause.