Borderline Personality Disorder

What is borderline personality disorder?

Borderline personality disorder is a serious mental illness that affects how a person feels about themselves and others and makes it hard to function in everyday life. The disorder often involves difficulty regulating emotions, leading to impulsivity, an unstable or often changing sense of self, and troubled relationships with others.

Effective treatments are available to manage the symptoms of borderline personality disorder. Learn more about the disorder, its diagnosis and treatment, and how to find help.

What are the signs and symptoms of borderline personality disorder?

People with borderline personality disorder often experience intense mood swings and uncertainty about how they see themselves. Their interests, values, and feelings can change quickly. They also tend to view things in extremes, such as all good or all bad. This is often seen in social interactions, which may swing from extreme closeness to extreme dislike, resulting in unstable relationships and emotional pain.

Other symptoms can include:

• Avoiding real or perceived abandonment, such as by jumping into or out of relationships quickly
• A pattern of intense and unstable relationships with family, friends, and loved ones
• High sensitivity to rejection and feelings of alienation or isolation
• A distorted and unstable self-image or sense of self
• Intense and highly variable moods, with episodes lasting from a few hours to a few days
• Chronic feelings of emptiness
• Inappropriate, intense anger or problems controlling anger
• Feelings of dissociation, such as being cut off from oneself, observing oneself from outside the body, or feeling disconnected from one’s surroundings
• Self-harming behavior, such as cutting
• Recurring thoughts of suicide, threats of suicide, or suicidal behaviors

Some people engage in impulsive or reckless behaviors, such as spending sprees, unsafe sex, substance use, dangerous driving, and binge eating. However, if these behaviors happen mostly during times of elevated mood or energy, they may be symptoms of another disorder, for example, a mood disorder, rather than borderline personality disorder.

Not everyone with borderline personality disorder experiences all these symptoms. The severity, frequency, and duration of symptoms vary depending on the person.

People with borderline personality disorder have a significantly higher rate of self-harm and suicidal thoughts and behavior than the general population. Anyone thinking of harming themselves or attempting suicide needs help right away.

What causes borderline personality disorder?

Although the exact cause of borderline personality disorder is unknown, research suggests that genetic, physical, environmental, and social factors may increase the risk of developing the disorder. These include the following risk factors.

• Family history: People with a close family member (such as a parent or sibling) with the disorder may be at a higher risk of developing borderline personality disorder.
• Brain structure and function: Research shows that people with borderline personality disorder may have structural and functional changes in the brain, especially in areas that control impulses and regulate emotions. However, it is unclear whether these brain changes are risk factors for the disorder or a product of having the disorder.
• Environmental, cultural, and social factors: Many people with borderline personality disorder report experiencing traumatic life events, such as abuse, neglect, maltreatment, abandonment, or hardship during childhood. Others may have been exposed to unstable, invalidating relationships or frequent interpersonal conflicts.

Although these factors may increase the risk for borderline personality disorder, experiencing them doesn’t mean a person will develop the disorder. Likewise, people without these risk factors can have the disorder as well.

How is borderline personality disorder diagnosed?

A licensed mental health professional can diagnose borderline personality disorder based on a thorough discussion of symptoms and personal and family history, including history of mental illness. A medical exam can further rule out other possible causes.

Borderline personality disorder is usually diagnosed in late adolescence or early adulthood. Occasionally, a person younger than 18 years will be diagnosed with the disorder if symptoms are severe and last at least a year.

What other conditions can co-occur with borderline personality disorder?

Borderline personality disorder often co-occurs with other mental and physical conditions. These can include mood disorders like depression and bipolar disorder, externalizing disorders like conduct problems and attention-deficit/hyperactivity disorder, and metabolic-related disorders like diabetes and obesity.

These co-occurring conditions can make it harder to diagnose and treat borderline personality disorder, especially if the symptoms overlap. For example, a person with borderline personality disorder may be more likely to experience symptoms of depression, post-traumatic stress disorder, bipolar disorder, anxiety disorders, substance use disorders, or eating disorders.

Overlaps between borderline personality disorder and other disorders can reflect shared features (for instance, impulsive behaviors are common in borderline personality disorder and a key symptom of bipolar disorder). However, symptoms of borderline personality disorder occur in the absence of significantly elevated mood seen during manic or hypomanic episodes, which is a key feature of bipolar disorder.

How is borderline personality disorder treated?

Evidence-based treatments have been shown to help many people with borderline personality disorder experience fewer and less severe symptoms, improve their functioning, and have a better quality of life. People with the disorder should receive treatment from a licensed mental health professional.

Many factors affect how long symptoms take to improve once treatment begins. It is important that people with borderline personality disorder and their loved ones be patient and receive support during treatment. It is also important to not only seek out—but stick with—treatment. Studies funded by the National Institute of Mental Health (NIMH) indicate that people with borderline personality disorder who do not receive adequate treatment are more likely to develop other chronic illnesses and are less likely to make healthy lifestyle choices.

Psychotherapy

Psychotherapy, or talk therapy, is the primary treatment for borderline personality disorder. Most psychotherapy occurs with a licensed, trained mental health professional in one-on-one sessions or with other people in group settings. Group sessions may help people with borderline personality disorder learn to interact more constructively with others and express themselves more effectively.

Psychotherapies used to treat borderline personality disorder include the following.

• Dialectical behavior therapy (DBT): This treatment was developed specifically for people with borderline personality disorder. DBT uses concepts of mindfulness or awareness of one’s present situation and emotional state. DBT also teaches skills to help people control intense emotions, reduce self-destructive behaviors, and improve relationships.
• Cognitive behavioral therapy (CBT): This treatment helps people identify and change core beliefs and behaviors that come from inaccurate perceptions of themselves and others and improve interactions with others. CBT can help reduce mood swings, anxiety symptoms, and self-harming or suicidal behaviors.

Therapy for caregivers and family members is often helpful. Having a loved one with borderline personality disorder can be stressful, and family members or caregivers may unintentionally act in ways that worsen symptoms.

Although more research is needed to determine how much family therapy helps with borderline personality disorder, studies of other mental disorders show that including family members can help support a person’s treatment. Families and caregivers can benefit from therapy by:

• Developing skills to understand and support a person with borderline personality disorder
• Learning about the needs and obstacles they face in caring for someone with the disorder and developing strategies to overcome them

Other forms of psychotherapy may also be used to teach people with borderline personality disorder specific skills or address specific symptoms. Learn more about psychotherapy.

Medication

The benefits of medication for borderline personality disorder are unclear, and it is not a first-line treatment for the disorder. However, in some cases, a health care provider may recommend medication as an add-on to psychotherapy to treat specific symptoms or co-occurring conditions such as mood swings or depression. Treatment with medication may require coordinated care from more than one provider.

Medications can cause side effects in some people. Talk to a provider about what to expect from a medication. Learn more about mental health medications. Read the most up-to-date information on medications, side effects, and warnings on the U.S. Food and Drug Administration (FDA) website .

How can I find help?

If you have concerns about your mental health, talk to a primary care provider. They can refer you to a qualified mental health professional, such as a psychologist, psychiatrist, or clinical social worker, who can help you figure out next steps. Find tips for talking with a health care provider about your mental health.

The Substance Abuse and Mental Health Services Administration (SAMHSA) has information on borderline personality disorder’s causes, symptoms, and treatment .

You can learn more about getting help on the NIMH website. You can also learn about finding support  and locating mental health services  in your area on the SAMHSA website.

How can I help a loved one with borderline personality disorder?

Here are some ways to help a friend or family member with borderline personality disorder:

• Learn about the disorder to better understand what your loved one is experiencing.
• Change can be difficult and frightening for people with borderline personality disorder, but things can improve with time. Offer emotional support, validation, understanding, patience, and encouragement.
• Encourage your loved one to ask about family therapy. It is also important that they receive appropriate treatment for any co-occurring mental and physical conditions.
• Help your loved one take their medications as prescribed and encourage them to discuss problems or concerns with their health care provider before stopping a medication or making any changes.
• Learn about your loved one’s treatment plan and find ways to help support their goals. Be open to learning new ways to offer support that are consistent with treatment goals.
• Encourage structure through daily scheduling and prioritizing a healthy lifestyle.
• Take comments about possible self-harm or suicide seriously. Encourage prompt contact with a mental health professional or the 988 Suicide & Crisis Lifeline  by calling or texting 988, if necessary.
• Seek counseling for yourself. Choose a different therapist than the one your friend or family member is seeing.

What are clinical trials and why are they important?

Clinical trials are research studies that look at ways to prevent, detect, or treat diseases and conditions. These studies help show whether a treatment is safe and effective in people. Some people join clinical trials to help doctors and researchers learn more about a disease and improve health care. Other people, such as those with health conditions, join to try treatments that aren’t widely available.

NIMH supports clinical trials across the United States. Talk to a health care provider about clinical trials and whether one is right for you. Learn more about participating in clinical trials.

For more information

Learn more about mental health disorders and topics. For information about various health topics, visit the National Library of Medicine’s MedlinePlus  resource.

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National Institutes of Health
Revised 2025