Personality Disorders

A Clinician’s Guide to Differentiating ADHD and Borderline Personality Disorder

BPD symptoms overlap with ADHD traits and features. Here, we review the nine symptoms of borderline personality disorder, examine how these symptoms may show up in ADHD, and differentiate these two distinct but related conditions.

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BPD Symptoms vs. ADHD: Distinguishing Similar Symptoms

Borderline personality disorder (BPD) — characterized by unstable interpersonal relationships, self-image and identity issues, and impulsivity — shares many traits and features with attention deficit hyperactivity disorder (ADHD), a comorbidity that is largely under-appreciated despite its significant clinical implications.

The ADHD-BPD overlap comes into focus when we look beyond the core symptoms of ADHD — inattention, hyperactivity, and/or impulsivity — and consider the full effect of ADHD and its related features, like dopamine deficiency and emotional dysregulation, on various domains of life. Through this lens, we can recognize how ADHD presents in ways that may resemble the symptoms of BPD, and how misdiagnosis may occur.

In addition to sharing symptoms, BPD and ADHD can co-occur and influence each other’s presentation. Differentiating BPD from ADHD isn’t just a matter of avoiding misattribution of symptoms, but of recognizing the possible presence of both conditions for adequate treatment.

To merit a BPD diagnosis, individuals must display at least five of the nine symptoms of BPD listed in each section below by early adulthood and in various contexts.1 Nearly all symptoms of BPD may seem to resemble symptoms of ADHD; understanding the ‘why’ of each symptom will help determine its relationship to ADHD and/or BPD.

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BPD Symptom #1: Frantic Efforts to Avoid Real or Imagined Abandonment

Individuals with BPD exhibit a deep fear of being alone and try to avoid feeling and/or being rejected and abandoned at all costs. This fear manifests in various ways and is connected to other symptoms of BPD. Some individuals, for example, describe feeling like they don’t exist when they are alone — as if their existence is only validated by the people around them. (See symptom #3 below.)

Fear of abandonment can cause people with BPD to misinterpret situations or events where no real rejection or lasting separation has taken place. They may become upset or angry, for example, when a friend is a few minutes late in meeting them, thinking that the friend is trying to avoid them.

BPD may cause people to engage in elaborate and desperate behaviors in a bid to hold on to their relationship(s), especially their romantic relationships. At the same time, people with BPD might experience difficulties connecting in those relationships.

The ADHD Context
Some individuals with ADHD also describe experiencing sensitivity to abandonment and rejection. (Rejection sensitive dysphoria, though not a clinical diagnosis, is a term frequently used in the ADHD community to describe intense pain in response to real or perceived rejection.) Some make serious efforts to avoid being alone. Unlike individuals with BPD, people with ADHD trace these experiences back to a drive to avoid boredom — one of the more dysphoric states for people with ADHD.

Because many people with ADHD have a very hard time entertaining and stimulating themselves, they may seek and find stimulation in social interactions. Engaging with others can make the bored ADHD brain feel present. Under-stimulation may lead to desperate bids for connection.

If a patient with ADHD is properly stimulated, they likely will not engage in frantic, desperate efforts to hold on to people. They may not even experience great concerns around abandonment.

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BPD Symptom #2: Unstable and Intense Interpersonal Relationships

The DSM-5 describes this symptom as follows: A pattern of unstable and intense interpersonal relationships characterized by alternating between extremes of idealization and devaluation.

People with BPD tend to engage in dichotomous thinking. They often perceive themselves and others in terms of good and bad, perfect and imperfect, being all in or all out, and other extremes. This tendency causes problems in interpersonal relationships, especially during dating and in early romantic relationships. The individual with BPD might view their partner as the hero of their lives — the be-all and end-all. Everything about their partner is perfect — until it’s not. Then, everything about that partner is awful.

This black-and-white, all-or-nothing pattern of thinking makes it difficult for people with BPD to connect and relate to others. At the same time, existing in the middle is often difficult for people with BPD. Navigating gray areas in relationships means trusting themselves and others, which is impaired in BPD.

The ADHD Context
People with ADHD may also alternate between idealization and devaluation in interpersonal relationships, particularly in romantic relationships. But these highs and lows come from varying stimulation levels — not from dichotomous thinking as seen in BPD.

People with ADHD may idealize their romantic partner and relationship during the honeymoon phase, when the newness of the relationship excites and stimulates their dopamine-seeking brain. As routine sets in, so does devaluation in some cases. The person with ADHD might think, “I don’t like this person as much because they aren’t engaging me enough.”

Interpersonal problems associated with ADHD are common but seldom as severe as they are in BPD. Many people with ADHD have strong, positive relationships.

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BPD Symptom #3: Identity Disturbance; Unstable Self-Image or Sense of Self

People with BPD may struggle greatly with knowing and understanding who they are — a concept that is often difficult to grasp for people who don’t have BPD.

Sense of self is markedly and persistently unstable in BPD. There may be sudden, dramatic shifts in goals, values, opinions, types of friends, and other parts of identity.

In many ways, people with BPD may try to gain a sense of self through relationships. They may affiliate themselves with someone they idealize and, by extension, begin to see themselves as “good.” Sense of self is also malleable and based upon where the individual with BPD thinks they will receive the most love, validation, and/or acceptance. This often results in unstable interpersonal relationships.

People with BPD also often describe feeling as if they don’t exist, especially when they are alone. In this way, being in the presence of others helps validate their existence. (See symptom #1.)

A healthy sense of self and identity (which most people develop) is like a fully formed key. For people with BPD, this key is either not fully formed, or its design is ever-changing, based upon the lock the person is trying to fit into at a given time.

The ADHD Context
Identity and sense-of-self issues may impact individuals with ADHD, but not to the degree or extent to which they manifest in BPD. Most people with ADHD do have a core sense of self and a solid identity, but they may struggle with certain elements around who they are.

Executive functioning and maturity delays, for example, are common in ADHD and may affect self-perception and the development of identity. This may explain why many adults with ADHD feel they haven’t achieved full adulthood, or consider themselves late bloomers.

Trying and struggling to find a niche or a place to fit — another common challenge among people with ADHD — also influences identity and sense of self. If people with BPD have incomplete or ever-changing keys, people with ADHD have complete keys, but they often struggle to find the right lock.

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BPD Symptom #4: Impulsivity

To meet this BPD criterion, individuals must display impulsivity in at least two areas that are potentially self-damaging (e.g., spending, sex, substance use, reckless driving, binge eating).
The ADHD Context
ADHD clearly and definitively overlaps with BPD here, as impulsivity is a hallmark symptom of ADHD. In ADHD and in BPD, the reasons for engaging in impulsive behaviors are similar — they serve as methods for grounding oneself, regulating emotions, and/or avoiding having to sit with difficult, painful feelings.
Why am I so weird? Concept image of a woman reflected through a puddle on a dark, rainy day
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BPD Symptom #5: Recurrent Suicidal Behavior, Gestures, Threats, or Self-Mutilating Behavior

About 10% of individuals with a BPD diagnosis will die by suicide.2

Individuals with BPD may talk of wanting to die or feeling a desire for death because they feel like they aren’t built for living in this world. They may say that they feel numb or not fully formed — feelings that fuel thoughts of suicide and lead to suicide attempts.

Self-harming behaviors are also common in BPD and are often associated with self-loathing and self-punishment. They may also be associated with efforts to relieve numbness and feelings of dissociation and depersonalization. Cutting, for example, produces pain and draws blood — all of which may affirm one’s existence.

The ADHD Context
Suicide risk is elevated in ADHD, even after controlling for depression, anxiety, PTSD, and other co-occurring disorders and variables.3

Certainly, suicidality arises from many factors, regardless of condition. But in ADHD — and unlike in BPD — suicidal ideation often seem to arise from feeling like one does not know how to live, rather than wanting to die. My patients with ADHD who struggle with suicidal thoughts will say things like, “I don’t know how to ‘adult’” and, “I don’t know how to figure out life.” They’d have a zest for life, they say, if only their executive function demands were reduced, or if they were only able to find their niche.

Individuals with ADHD (especially teen girls) also face a greater risk for self-harming behaviors than do people without ADHD.4 5 Self-harming behaviors in ADHD are often tied to sensation seeking and dopamine release. (Not everything that is stimulating is necessarily pleasurable.) People with ADHD may also self-harm to relieve tension and ground themselves.

borderline personality disorder symptom of irritability
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BPD Symptom #6: Affective Instability Due to Marked Reactivity of Mood

Intense episodic dysphoria, irritability, anxiety, despair, and other mood issues are common in BPD, usually lasting a few hours and rarely more than a few days.

BPD is also highly comorbid with mood disorders, like depression and bipolar spectrum disorders.6 7 Bipolar disorders overlap so much with BPD that some researchers have introduced the idea of BPD being part of the bipolar spectrum.8

Extreme mood changes in BPD may arise from internal and external triggers, like an internal sense of agitation or problems in interpersonal relationships, respectively. Hypersensitivity and dichotomous thinking may distort perceptions and play a major role in intense reactivity.

The ADHD Context
Emotional regulation challenges are common in ADHD, but they are not comparable to the rapidly shifting emotional states and degrees of reactivity and instability seen in BPD. Reactions are significantly shorter lasting in ADHD, and they are not episodic.

Mood changes also tend to be more context-based in ADHD and in response to an external event, not so much to a sudden internal feeling.

(More on ADHD and emotional dysregulation in symptom #8 below.)

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BPD Symptom #7: Chronic Feelings of Emptiness

Feelings of emptiness are persistent in BPD, and tie into the other symptoms and features of the personality disorder, such as self-harm behaviors, impulsivity, an unstable sense of self, and efforts to avoid abandonment.
The ADHD Context
Feelings of emptiness may come up in ADHD when the individual is under-stimulated. Unlike in BPD, these feelings arise only occasionally and are not chronic.

Since feelings of emptiness are modulated by level of stimulation, these feelings can quickly go away once the individual finds something that fulfills them in that moment, like getting in touch with a friend or engaging in their favorite hobby.

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BPD Symptom #8: Inappropriate, Intense Anger or Difficulty Controlling Anger

Frequent temper outbursts, extreme sarcasm, bitterness, rage, and recurrent physical fights are all signs of inappropriate, intense anger and/or difficulty controlling anger that mark BPD. Anger is a common response to feeling slighted by a loved one, whether the feeling is grounded in perception or reality. With BPD’s dichotomous thinking, shame and guilt often follow these expressions of anger, as they contribute to the individual’s sense of being a bad person.

Anger in BPD isn’t always external. “Quiet BPD” has emerged as a term that describes, in part, BPD that is characterized by internalized anger, rage, and emotional episodes — in contrast to the outward emotional displays more commonly associated with this personality disorder.

The ADHD Context
Difficulty suppressing and soothing strong emotions is one of the central challenges of deficient emotional self-regulation (DESR), which is associated with ADHD emotional dysregulation.9

It’s why individuals with ADHD may experience intense anger that is difficult to control. Even so, anger in ADHD is often a normal response to a stressor (which isn’t always the case with BPD); it’s the anger’s intensity that stands out in ADHD.

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Credit: Steven Puetzer/Getty Images
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BPD Symptom #9: Transient, Stress-Related Paranoid Ideation or Severe Dissociative Symptoms

The “borderline” in BPD comes from early conceptualizations of the personality disorder, wherein individuals with BPD were seen as bordering on psychosis (e.g., having experiences and thoughts that aren’t always based in reality.) Paranoid ideation and dissociative symptoms (e.g., feeling disconnected from the body and the world) fall into this kind of “slippery” thinking.

These episodes and symptoms tend to be transient, lasting minutes or hours, and occur most frequently in response to real or imagined abandonment. (See symptom #1.)

The ADHD Context
Paranoia is not an aspect or characteristic of ADHD. Inattention and distractibility may mimic dissociation, though what’s ultimately at play is vastly different from what is happening in BPD.

An individual with ADHD, for example, may be lost in thought, zoned out, or distracted to the point of appearing disconnected from the present moment. This is not the same as the experience of dissociation, which describes a disconnect from one’s body, thoughts, surroundings, and sense of reality. Even when an individual with ADHD appears disconnected, they are still connected and grounded internally or externally to something (likely a stimulating thought). Whether someone with ADHD becomes disengaged from the present often depends on how stimulated they are. Dissociative symptoms in BPD, on the other hand, are not modulated by stimulation, but by stress.

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BPD Symptoms vs. ADHD Symptoms: Next Steps

The content for this article was derived, in part, from the ADDitude ADHD Experts webinar titled, “Borderline Personality Disorder & Its Connection to ADHD” [Video Replay & Podcast #446] with Roberto Olivardia, Ph.D., which was broadcast on March 15, 2023.

Since 1998, ADDitude has worked to provide ADHD education and guidance through webinars, newsletters, community engagement, and its groundbreaking magazine. To support ADDitude's mission, please consider subscribing. Your readership and support help make our content and outreach possible. Thank you.


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9 Surman, C. B., Biederman, J., Spencer, T., Miller, C. A., McDermott, K. M., & Faraone, S. V. (2013). Understanding deficient emotional self-regulation in adults with attention deficit hyperactivity disorder: a controlled study. Attention deficit and hyperactivity disorders, 5(3), 273–281.