MAOA What? The Genetic Link Between Borderline Personality Disorder and Bipolar Disorder

Wednesday, September 24, 2014 by Meg   •   Filed under General

Borderline Personality Disorder (BPD) can be a very difficult issue to deal with. It usually shows up as unstable or turbulent emotions, which may result in impulsivity and troubled relationships with others.

In the view of most psychotherapists, Borderline Personality Disorder often results from early environments steeped in fear of abandonment or abuse and neglect which leads to insecure attachment patterns. 

But this doesn’t mean genes don’t matter. Because like jeans that chafe when they don’t fit right, genes can irritate certain parts of your body and make them all out of whack until you break down and buy the infamous “mom jeans” or just settle for yoga pants like any reasonable person would. 

Wait…no, that’s not right. Genes just mess with your brain and make you more susceptible to these conditions. Okay, that makes more sense. But your inside genes and your outside jean-wearing environment work together to trigger disorder.

Borderline Personality Disorder and Genetics (not to be confused with jean-etics)

If the examined (and more verified) genetic links in disorders like psychopathy and depression are any indication, the genes need to be turned on to manifest. So even if you come with genetics that you’d like to bitch slap, you still need an environmental key that opens Pandora’s box of extreme moods and trouble with self regulation.

Your environment in utero can turn on genes or increase susceptibility to stress responses (say through a stressful pregnancy), as described by paleobiologist Robert Sapolsky in Why Zebras Don’t Get Ulcers12. But there generally remains some early childhood triggers as well. Having a genetic predisposition to certain personality traits such as vulnerability or aggression may make one more prone to additional environmental strain that makes these conditions worse1, as is the case with depression (find out more here in Is Depression A Physical Illness?). 

The gist is that if I am genetically predisposed to a condition, it is likely that my caregivers may have some of those same traits as well. And, if my tendencies happen to include, let’s say aggressiveness, those around me may tend towards aggressive behaviors to deal with me, making me feel less safe and deepening the disorder itself in a vicious cycle of genetics, modeling and enhanced stress responsiveness. 

Deep stuff. (That’s what she said.)

So what are these genes that need to be turned on in Borderline Personality Disorder? 

Some studies indicate that genes related to the serotonergic system might have a modulating effect in borderline personality disorder2, as might those related to Nitric oxide synthase (NOS), rennin-angiotensin-related genes, Dopamine B-hidroxylase and the cannabionoid receptor gene, though other traits that control aggression and impulsiveness may also play a role2. Other studies go further, citing Monoamine Oxidase A (MAOA), a mitochondrial enzyme that helps break down certain neurotransmitters such as serotonin and norepinephrine3. This gene has also been linked to aggression, impulsivity, suicide and mood liability3


Here’s the rub, guys, because that’s a shit load of brain talk. Genes use proteins to yell at other cells in the body like a big jerk boss calling out orders from his office. Genes  don’t do anything themselves, because genes are lazy assholes.They rely on enzymes to take genetic information and turn it into the protein recipe that everyone else can understand.

Those enzymes are like interpreters.  The lazy boss (genes) give instructions, the enzymes take that information and build a single strand molecule of RNA which goes out to make the protein which bull horns the instructions to other parts of the body.

Kinda. It’s more complicated than that, but that’s good enough for our purposes here. Because what we really need to know is that MAOA is an enzyme that works for genes in the “Neurotransmitters R Us” department. And neurotransmitters like serotonin have a big impact on emotional wellbeing, from depression to anxiety to rage. So depending on how MAOA does its job in breaking down instructions, we might feel out-of-control rage-y or where-have-you-been-all-my-life love-y or oscillate between the two, depending on what’s happening around us.

But there is a little snafu in this whole genetic thingamabob. 

That’s right, thingamabob. It’s a clinical term, like bat-shit stupid. Trust me. 

The Overlap Between Borderline Personality and Bipolar Disorder

The snafu is that this mood lability thing has led researchers to wonder about the overlap between Borderline Personality Disorder and other conditions, most notably Bipolar Disorder. Aside from the fact that their most obvious similarity will prevent me from using the acronym BPD for the rest of this article, they do have some similarities that can lead to misdiagnosis5.

There are a few different types of Bipolar Disorder and the one you have is diagnosed based on how long your periods of depression and mania last (this will be discussed at length in future posts as will the evolutionary benefits of these conditions). For our purposes here, Bipolar Disorder is most often characterized by periods of depression between periods of being extremely happy and energetic, anxious or angry. So in both Borderline and Bipolar, there tends to be mood disturbances, some propensity for extreme emotions and trouble self regulating (or controlling those emotions).

Just to give you some frame of reference, Borderline Personality Disorder occurs in around 1.6% of individuals in any given year11. Bipolar Disorder occurs 2.6% of the population11. And somewhere between eight and eighteen percent of individuals diagnosed with one of these conditions have both at the same time4

This overlap is not necessarily surprising as researchers have discovered that the same group of enzymes that increase risk for borderline personality traits may also be related to the development of bipolar conditions.

Bipolar Disorder Risk and MAOA

A number of studies support the notion that MAOA variants or neighboring genes may play a role in the development of bipolar disorder6,7,8. Some note that it might be functional variants in other regions of the MAOA gene or neighboring genes that affect bipolar affective disorder risk8. Other studies confirm this, but note the involvement of a specific MAOA gene known as the MAOA-CA repeat gene in the development of bipolar disorder9. The MAOA-CA codes for a catabolic enzyme of serotonin. This MAOA-CA gene had also been linked to the development of ADHD10

Obviously all these neurotransmitter issues cause a wide variety of problems from trouble with aggression, to trouble with mood regulation, to mood swings or extreme emotions.But what makes one develop bipolar and one develop borderline while others get a double whammy is not entirely clear though it may have to do with other genetic factors, gene expressions and differences in early environment. 

The brain is nothing if not complicated as fuck. But understanding that these conditions are at least partially the result of a genetic link may help some to feel more normal in their own skin. 

No matter which symptoms you end up with, there is always treatment available to combat the wonky regulation of neurotransmitters and help you avoid trying to bitch slap your genes. Because smacking genetics is way harder than finding jeans that fit. 

Well, sometimes. 

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Topic-Relevant Resources

Mindfulness for Borderline Personality Disorder: Relieve Your Suffering Using the Core Skill of Dialectical Behavior Therapy
How to use mindfulness tactics and Dialectical Behavioral Therapy (DBT) in the treatment of Borderline Personality Disorder.

Borderline Personality Disorder Demystified: An Essential Guide for Understanding and Living with BPD
All the basics on Borderline Personality Disorder including helpful techniques to cope with symptoms.

The Bipolar Disorder Survival Guide, Second Edition: What You and Your Family Need to Know
Great resource for understanding and living with Bipolar Disorder.

Loving Someone with Borderline Personality Disorder: How to Keep Out-of-Control Emotions from Destroying Your Relationship
Great tips for fostering healthy relationships for sufferers and partners of those with Bipolar Disorder.

I Hate You--Don't Leave Me: Understanding the Borderline Personality
A look inside Borderline Personality Disorders and effective treatments.