Borderline personality disorder (BPD) is diagnosed when at least five of nine specific
signs form a long-lasting pattern. Below, each sign is explained in plain language with
everyday examples. This guide is educational: only a licensed mental health professional can diagnose BPD.
The National Institute of Mental Health describes BPD as a mental illness that severely affects a person’s ability to regulate their emotions. That loss of emotional control can increase impulsivity, change how people see themselves, and strain their relationships. In a national survey, about 1.4% of US adults had BPD in the past year. It is usually diagnosed in late adolescence or early adulthood, and effective treatments are available.
The American Psychiatric Association’s diagnostic manual (DSM-5) lists nine criteria. The wording below is a plain-language summary, not the official text.
Frantic efforts to avoid being left, whether the threat is real or imagined. For example: panicking when a partner is late home, or repeatedly checking whether a friend is upset with you.
Relationships that swing between idealizing someone and devaluing them, from "all good" to "all bad". For example: seeing a new friend as perfect, then feeling deeply betrayed after one disagreement.
A self-image or sense of identity that shifts markedly and often. For example: frequently changing goals, values or career plans, or feeling unsure who you really are.
Impulsive actions in at least two areas that can cause harm, such as spending, sex, substance use, reckless driving or binge eating.
Recurring suicidal thoughts, threats or behavior, or self-harm such as cutting. People with BPD have a much higher rate of self-harm and suicidal behavior than the general population.
Strong emotional reactions to everyday events: episodes of intense sadness, irritability or anxiety that last from a few hours to a few days. This short timing is one way clinicians tell BPD apart from bipolar disorder, where mood episodes last days to weeks.
A lasting hollow or empty feeling, even when life seems to be going well.
Anger that is out of proportion to the situation or hard to manage, such as frequent outbursts, constant irritation or getting into fights. It is often followed by shame or guilt.
Under stress, brief suspicious or paranoid thoughts, or dissociation: feeling cut off from yourself, watching yourself from outside your body, or feeling disconnected from your surroundings.
At least five of the nine. They must form a lasting pattern that began by early adulthood and shows up across many parts of life, such as home, work and relationships. A clinician also checks whether something else explains them better. Because only five of nine are needed, two people with BPD can have very different experiences. A few of these signs during a hard period do not mean someone has BPD. Some people experience these signs mostly on the inside, through self-blame and withdrawal. This is sometimes called quiet BPD.
BPD often occurs alongside other conditions, and some signs overlap. These are the most common ones clinicians consider.
| Condition | Signs it can share with BPD | A key difference |
|---|---|---|
|
Bipolar disorder |
Mood changes, impulsive
behavior |
Mood episodes last days to
weeks and include mania or
hypomania. BPD moods shift
within hours, without those
periods of elevated mood. |
|
Depression |
Sadness, emptiness,
hopelessness |
Low mood lasts most of the day,
nearly every day, for at least
two weeks, rather than shifting
quickly with events. |
|
Pos-traumatic stress disorder |
ntense emotions, dissociation,
difficulty trusting others |
Symptoms follow a traumatic
event and center on it, such as
flashbacks and avoiding
reminders. |
Any of these can also occur alongside BPD, which is why a full evaluation matters more than any one sign.
Write down which signs you recognize, how long they've lasted and where they show up. Our free BPD traits checklist can help you organize this, with no email needed.
A primary care provider can refer you to a psychologist, psychiatrist or clinical social worker. Read how to get diagnosed with BPD.
Therapies built for BPD, such as dialectical behavior therapy, help many people. Read about BPD treatment and DBT.
read how to support someone with BPD.
Frantic efforts to avoid real or imagined abandonment. 2) Unstable, intense relationships that swing between idealizing and devaluing. 3) An unstable self-image or sense of self. 4) Impulsivity in at least two potentially self-damaging areas. 5) Recurring suicidal behavior, threats or self-harm. 6) Intense, quickly shifting moods. 7) Chronic feelings of emptiness. 8) Intense or hard-to-control anger. 9) Stress-related paranoid thoughts or severe dissociation.
At least five of the nine DSM-5 criteria, showing up as a long-term pattern across different areas of life, usually since early adulthood. A professional also checks that the symptoms aren’t better explained by another condition.
The core feature is difficulty regulating emotions, which affects how people see themselves, how they relate to others and how they act on impulse. Fear of abandonment and intense, unstable relationships are among the most recognized traits.
Yes. Many people show one or two of these traits at times, especially under stress. A diagnosis needs at least five, as a lasting pattern across many areas of life.
Often, yes. In a 10-year study of 290 people with BPD, 93% had a period of at least two years without meeting the criteria. Read more about recovery and treatment.
National Institute of Mental Health: Borderline Personality Disorder (revised 2025)
National Institute of Mental Health: Personality Disorders statistics (1.4% past-year
prevalence)
American Psychiatric Association: DSM-5-TR (2022)
Zanarini MC et al.Time to attainment of recovery from borderline personality disorder.
American Journal of Psychiatry, 2010
National Institute of Mental Health: Depression and PTSD
