The Heart Of Borderline Personality Disorder: Causes And Risk Factors

Reviewed by Whitney White, MS CMHC, NCC., LPC

Published 10/14/2022

Borderline Personality Disorder is not typically considered a simple dinner table discussion fare, and many of its causes and symptoms can easily be misunderstood or incorrectly described. The heart of Borderline Personality is far less mysterious and frightening than a quick glance into the disorder might have you believe, however, and actually begins in childhood.

The Basics: What Is a Personality Disorder?

The term “disorder” is relatively common, but the phrase “personality disorder” is far more often misunderstood. Unlike mood disorders, personality disorders are focused on behavior, thought patterns, and lines of reasoning. While many mental disorders are linked to biological input and similar issues, personality disorders do not typically have significant roots in biology (though genetics may play a role). Instead, a personality disorder is likely to develop on the heels of learned behavior during childhood or after a traumatic experience.

Borderline Personality Disorder is a type of personality disorder that bears the marks of all personality disorders; namely, an inability to or a difficulty with healthy brain function, particularly where relationships, communication, and daily functioning are concerned. The most pressing symptoms of Borderline Personality Disorder include:

  • Fear and avoidance of abandonment. People with Borderline Personality Disorder are likely to have been abandoned in some way, which leads to a constant fear of being abandoned again, and concentrated efforts to avoid abandonment in the future.
  • Deep feelings of mistrust. People with Borderline Personality Disorder often experience deep and abiding feelings of mistrust, even in relationships without a history of abandonment, hurt, or pain. Family, friends, and authority figures may all be regarded with a lingering sense of mistrust.
  • Difficulty in relationships. Because people with Borderline Personality Disorder struggle with mistrust, mood swings, and a fear of abandonment, they are often unable or unwilling to maintain close-knit relationships.
  • Mood swings and anger. “BPD brain” can cause severe swings in mood—swings that can last a few minutes, a few hours, or up to a few days. People with Borderline Personality Disorder might be described as “prickly” or “unpredictable” as a result, as they may shift without cause or warning, between happy, angry, and sad or may move quickly and easily from admiration to disdain.
  • Impulsive or dangerous behavior. People with BPD often find themselves engaging in impulsive or dangerous behavior, which may include addiction to substances, gambling in amounts that exceed their ability to pay, or cutting or other methods of self-harm.

Although not each and every one of these symptoms is required to receive a BPD diagnosis, these are the most common indications that BPD is at play. Online tests can lend greater insight into the likelihood of having Borderline Personality Disorder—brain-based symptoms and behavior-based symptoms alike.

What Causes Borderline Personality Disorder

BPD causes vary, and most are heavily centered on childhood. While people often associated BPD with overtly traumatic or abusive childhoods, this is not necessarily the case; many children experience intense abuse, neglect, and trauma during childhood without having had parents or authority figures who physically harmed them, or overtly insulted or belittled them. While childhood is typically at the root of BPD, teasing out the different childhood causes is far more difficult—and quite complex.

A discussion of Borderline Personality Disorder etiology would be remiss without a thorough discussion of childhood experiences and the environment. A childhood home in which stability was absent could contribute to the onset of Borderline Personality Disorder. Because children rely heavily on parents, authority figures, and other family members to shape their world and worldview, and create a safety net for them to thrive in, homes characterized by instability can set the stage for children to experience severe shifts in emotional states, behaviors, and expectations.

Childhood homes marked by parental mental illness—or even sibling mental illness—can also be found at the root of Borderline Personality Disorder. In what is perhaps a fusion of nature and nurture, homes with mental illness (and in particular, untreated mental illness) may contribute to BPD development. This is also due to the unpredictable, unstable, and unknown nature of many mental illnesses that go without consistent or effective treatment. A member of the home does not necessarily need to have BPD to contribute to a child’s eventual BPD diagnosis. Anxiety disorders, depressive disorders, and other mental health issues can all be a contributing factor.

Bullying can also cause a break in a child’s ability to feel safe, known, and heard, which can lend another layer to the likelihood of developing BPD—particularly if bullying was reported and continued without help, or if it was ongoing and consistent. Bullying is problematic for many reasons and can be the source of poor self-image and increased anxiety, but it can also push children toward BPD because it takes a sense of safety and stability away as well. A child who is bullied in school, for instance, attends a place colored by fear and uncertainty 5 days per week, for at least 7 hours each day, effectively being forced to exist in a space that is mentally unhealthy and even downright dangerous.

Borderline Personality Disorder: Risk Factors

As is the case with any mental disorder, the exact cause may not be known; instead, there are a series of likely causes, each of them influenced by risk factors. The most common risk factors associated with BPD include:

  • Abandonment in childhood. People with BPD may have been abandoned in childhood, though the exact form of that abandonment can vary. For some, abandonment meant losing a parent to death early on. It could mean losing a parent to an emotional divorce and never seeing a parent again. It could even mean feeling abandoned by a trusted friend who suddenly seemed to “turn on” them. Abandonment takes on many forms, some of them more concrete to quantify than others.
  • Sexual, physical, and/or emotional abuse. Abuse has a lasting, intense impact on an individual’s development, and any type of abuse in childhood leads to an increased risk of developing BPD in adolescence and adulthood. Abuse need not have been committed by a close friend, relative, or loved one to potentially increase the risk of BPD.
  • Poor childhood communication. Because communication is at the core of virtually every relationship, children who were consistently exposed to poor or problematic communication habits are at greater risk of developing Borderline Personality Disorder.
  • Consistently unstable home lives. Children who experience a great deal of instability in childhood are at increased risk for BPD. As with abandonment, instability can look different for everyone, and can vary widely in how severely it impacts a child. For some, constant relocating is a form of instability, while for others, instability comes more often in the form of unstable financial situations.

Risk factors and causes are often blurred in Borderline Personality Disorder. Causes and risk factors can interact with one another and converge until the two are virtually indistinguishable from the other. As of yet, there is no concrete evidence as to why some children experience trauma, abuse, and instability without effects as adverse as BPD, and some do, making prevention a difficult task.

Borderline Personality Disorder: Rooted in Childhood

Painful though it may be to acknowledge, what causes BPD is firmly entrenched in childhood and adolescence, making BPD a symptom of a child not being cared for in the way that a child needs. Some of this is based almost entirely on the family unit, and some of it is indicative of larger, more systemic issues surrounding poverty, and race,  despite the best intentions of parents, friends, and family. Far from being an indicator of a flaw or some form of defect, Borderline Personality Disorder is, in effect, a series of unhealthy coping mechanisms designed to offer aid in figuring out the world around the child who is developing BPD symptoms.

The Heart of BPD

Although the phrase “personality disorder” carries with it all manner of negative connotations, Borderline Personality Disorder is not synonymous with violence, danger, or even someone with whom a relationship is impossibly volatile or perpetually unhealthy. Instead, Borderline Personality Disorder is a mental health condition in which an unsafe and problematic childhood had a profound and lasting effect on someone’s mental and emotional development. Although people with Borderline Personality Disorder may experience intense mood swings that can involve violence, the condition itself is not inherently dangerous, and if violence does come into play, it is often at the behest of another issue, such as unresolved conflict or untreated mood disorders.

Borderline Personality Disorder can have a massive impact on a person’s overall health and wellbeing, and those with the disorder often feel as though they are uniquely broken, or uniquely incapable of being loved. While this feeling is certainly understandable, in light of all that people with BPD have likely faced, one of the most important steps in treating BPD is the recognition that a personality disorder is not an identity. Someone with BPD will have behaviors and thought patterns influenced and altered by their disorder, but they are not uniquely unlovable or uniquely incapable of relationships and healthy functioning. Instead, people with BPD have a series of traits, processes, and patterns borne of abandonment, trauma, and fear—traits, processes, and patterns that can be unlearned, just as they were learned.