Hi there!
I am writing a new booklet, the ABCs of BPD, and wanted to share this with you about causes of BPD. Have fun!
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The Causes of BPD
Perhaps you’ve already heard a lot of theories—that people have BPD because of how they were raised as children. Or that it has something to do with a “chemical imbalance.”
The debate about what causes any kind of mental illness—biology or the environment—is as old as the question of which came first, the chicken or the egg.
But we really can’t look at those two things as opposites. Instead, consider them a halves of a circle. Biology and environment both contribute to Borderline Personality Disorder. But the more we learn about the brain, the more we’re discovering that biology plays a powerful, perhaps even dominant role in how mental illness strikes.
Malfunctions in the brain may explain a lot about BPD behavior. After you learn about them, it may be easier to empathize with your loved one who has BPD and, especially, not take things personally.
It may also help you pinpoint where things are going wrong, even if you’re not sure why. And if you’re a parent, it can ease the burden of guilt of the assumption that BPD is caused by abuse.
A helpful book in understanding how BPD works, how it may be caused, and how it can be treated is Borderline Personality Demystified by Robert O. Friedel, M.D. Dr. Friedel, who contributed to our understanding of this subject, offers detailed and scientifically accurate information about brain functioning.
Our focus here is not to make you a brain surgeon, but to explain enough so you can really see and feel how the disorder—an entity into itself—affects your loved one’s personality and how it affects you, themselves, and others.
First, we’ll explain the biological contribution, which can be divided into three parts: the physical brain, the chemical brain, and genetics. The physical brain is like the “hardware” and the chemical brain is like “software.” Genetics provides the “blueprint.”
The physical and the chemical brain are actually inseparable. But to make this a bit easier to understand, we’ll treat them separately.
The Physical Brain
Over the last few decades, says Dr. Friedel, we’ve developed new scientific tools for looking inside the brain such as PET scanners and MRI scanners. These tools have made it possible to see how the physical brains of people with BPD function differently than do other people’s brains.
We can look at these brain scans of people with BPD and a normal control subject and actually see in bright yellow, red, and blue that the brains of people with BPD are different. The “emotional” centers of the brain are more active, and the “logical” parts are underactive.
Think of the brain as filled with circuits, like a computer. Instead of wires and microchips, however, the brain’s circuits are made up of 100 billion neurons, or brain cells.
These brain cells are specialized, grouped in specific structures located in certain areas of the brain. These structures have names like the “cerebral cortex” and the “limbic system.” These specific structures are involved in certain activities, such as thinking, reasoning, emotion, or movement. Different areas have different “jobs,” yet they are interwoven and function together.
If something goes wrong in the sections of the brain that control perception and reasoning, we may suffer from disordered thinking. If something goes wrong in different sections, those that control emotion, we may have emotional problems. If something goes wrong in the parts that control impulsiveness, we may have difficulty resisting our impulses.
This is an active area of research right now. For example, one 2005 study found that lesions in one section of the brain may contribute to some core characteristics of borderline personality disorder, especially impulsivity. Another study found that malfunctions in another region of the brain may actually make it easier for people to kill themselves or try to do so.
The Chemical Brain
The brain cells that make up the brain’s structure don’t just sit there—they communicate with each other. They do so through powerful chemicals called neurotransmitters. Neurotransmitters are the chemical messengers that transmit signals from one neuron (brain cell) to another. The communication between neurons maintains all body functions, and informs us when a fly lands on our hand or when we have pain.
The brain requires a very precise balance in the level of various neurotransmitters. A mountain of research shows that when those levels aren’t exactly right, the result can wreak havoc on how we think, feel, and act.
We know of about 50 neurotransmitters. Most have at least one special job in controlling the brain and bodily functions. Some have more than one.
For instance, the neurotransmitter serotonin helps regulate body temperature and our ability to fall asleep. It also plays a role in mental health conditions such as BPD, depression, anorexia, and obsessive-compulsive disorder.
Dr. Joe Carver (
http://www.drjoecarver.com, another great resource) suggests we think of these neurotransmitters like the fluids in our cars: engine oil, transmission fluid, brake fluid, or anti-freeze. In a car, we can measure the levels of those fluids with meters or dipsticks.
Unfortunately, the body doesn't have a built-in dipstick for neurotransmitters, says Dr. Carver. Instead, professionals evaluate neurotransmitter levels by looking for indicators in thought, behavior, mood, perception, or speech that are considered related to levels of certain neurotransmitters.
In people with BPD, Dr. Friedel says, some of those circuits just don’t work properly. Greatly simplified, the levels of certain neurotransmitters are too low, too high, or have one of many other impairments. This can happen for a multitude of reasons.
For people with BPD it’s usually the same ones: ones that control how we think, reason and process information; ones that control emotion; and ones that control impulses.
Genetics and the Brain
Parents who have a BP child and another child without BPD may wonder why the two are different. The answer may be in our genes.
We inherit our genes from our biological parents. They determine things such as what color hair or eyes we have. They affect other traits. And they can play a role in disease as well.
For instance, someone who is diabetic has inherited a group of genes that together cause diabetes. Other mental illnesses, such as bipolar disorder, appear to be passed on genetically. Even alcoholism has now been linked to certain genes.
Dr. Friedel says there appear to be at least two, and perhaps four or five, genes that influence the traits that make up Borderline Personality Disorder: different genes may control problems with impulsivity; emotional regulation; or the thinking and perceiving powers of the brain.
So, strictly speaking, it isn’t BPD that can be inherited. Instead, it’s the traits that taken together make up BPD that are passed on—trades such as aggressiveness, depression, excitability, quickness to anger, or susceptibility to addiction.
Because several different genes can be involved with BPD, this helps explain why in the same family one person might have BPD and another not. Two parents, neither of whom have BPD, might still have some of the genes that can lead to it.
Suppose they have three children. Two of those children may be born without all of the genes needed that would lead to BPD, while, in the third, the genes may combine in just the way necessary for BPD to occur.
This information should be reassuring for parents of people with BPD. As Dr. Friedel points out, you don’t pick your genes, and you don’t pick the genes you pass on to your children. This is just the way human biology works.
