It Runs in Families: Heritability, Biology, and/or Environmental Influences

“Although BPD has long been ascribed to problematic parenting, scientists now believe that the borderline personality develops out of a neurobiological 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 caretaking in some way seems to activate it….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 Harvard psychiatrist John Gunderson, director of the Borderline Personality Disorder Center at McLean Hospital. 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.'” (Elizabeth Svoboda, “The Chaos That Borderline Personality Can Generate,Psychology Today, September 2, 2013)

Heritability (a genetic predisposition) estimates of BPD ranges: 50-60%:

Consistent with studies on the heritability of personality traits broadly.

Prevailing view is that it is the traits or trait clusters (Emotional Instability, Behavioral Instability, and Disturbed Interpersonal Relatedness), rather than the disorder itself, that is heritable.

(Barbara Stanley, “Unraveling (some of) The Mystery of Borderline Personality Disorder Have we been barking up the wrong tree?” [most recent citation 2010]— Barbara Stanley, Ph.D., Director, Suicide Intervention Center Director, Suicide Intervention Center Professor of Clinical Psychology Professor of Clinical Psychology Department of Psychiatry Columbia University, Slide 27, Slide 6)

“Genetic causes for BPD were largely ignored until the first significant twin study estimated its heritability at 69% about 17 years ago (Torgersen et al., 2000). Subsequent research has lowered this estimate, but convincingly confirms that BPD’s heritability accounts for more than half the variance in whether BPD develops (Distel et al., 2010; Gunderson et al., 2011; Kendler et al., 2011). As noted earlier, this research has also confirmed an underlying unifying common pathway genetic model. This research now requires theories about BPD’s core to account for the major role played by genes and to propose what the nature of the unifying genetic disposition is….In summary, the theories are highly diverse in their efforts to integrate BPD’s genetic disposition. Although both excessive emotionality and excessive aggression might logically be considered as promising candidates for BPD’s genetic disposition, this perspective has not been adopted by the theories. The Excessive Anger, Emotional Dysregulation [with its Biosocial theory], and Failed Mentalization theories all identify top-down cortical failures of organization, perception, or regulation as BPD’s core. Of these, only the Failed Mentalization theory has undertaken efforts to incorporate BPD’s genetics, but the nature of what comprises this genetic determination remains unresolved. The Excessive Aggression theory stands alone in seeing a conflictual, rather than deficit, core for BPD. The Interpersonal Hypersensitivity theory stands alone in seeing BPD’s core as genetic.”

John G. Gunderson, Alan Fruzzetti, Brandon Unruh, and Lois Choi-Kain, “Competing Theories of Borderline Personality Disorder “Journal of Personality Disorders, 32(2), 148-167,2018.

*What does it mean if a disorder seems to run in my family?

“A particular disorder might be described as ‘running in a family’ if more than one person in the family has the condition. Some disorders that affect multiple family members are caused by gene mutations, which can be inherited (passed down from parent to child). Other conditions that appear to run in families are not caused by mutations in single genes. Instead, environmental factors such as dietary habits or a combination of genetic and environmental factors are responsible for these disorders.

It is not always easy to determine whether a condition in a family is inherited. A genetics professional can use a person’s family history (a record of health information about a person’s immediate and extended family) to help determine whether a disorder has a genetic component. He or she will ask about the health of people from several generations of the family, usually first-, second-, and third-degree relatives.”