Borderline Personality Disorder Symptoms in Young People


Borderline personality disorder (BPD) is a personality disorder that often causes people to struggle with self-image, mood swings, impulse control, fear of abandonment, and low very feelings of self-worth. It is the most commonly recognised personality disorder.

What is Borderline Personality Disorder?

It is important to clarify that the term ‘personality disorder’ does not suggest there is anything wrong with your personality. The way that an individual diagnosed with a personality disorder views themselves and relates to others is affected so greatly by negative life experiences that they experience significant emotional difficulties leading to complex and ongoing problems with daily life.

BPD regularly first appears in teenagers and young adults, but often takes some time to be diagnosed.

About 5% of the UK population are diagnosed with some form of personality disorder. Around one in 100 people have BPD, affecting men and women equally, although it is recognised that women are more likely to be given a diagnosis of BPD than men.

It is common for people with BPD to have co-occurring disorders, including depression, bipolar disorder, substance use disorder and eating disorders.

Symptoms of Borderline Personality Disorder (BPD)

BPD symptoms can be grouped into four main areas:

Emotional Instability

 The psychological term for emotional instability is affective dysregulation.

People with BPD often experience very intense emotions that can be difficult to manage or control. It is common for people with BPD to engage in self-injurious behaviour to cope with these emotions. Self-harming behaviours are often an attempt to escape painful feelings and overwhelming emotions.

Emotional instability is one symptom of BPD that can cause misdiagnosis of other mental health conditions such as bipolar disorder, which is a mood disorder where an individual’s mood ranges from depressed to elevated mania or hypomania.

Disrupted Patterns of Thinking or Perception

People with BPD have a tendency to think in extremes and experience “black-or-white” thinking where thoughts become polarised. People with BPD often struggle to see the complexity in people and situations, or ‘see the grey’ and are sometimes unable to recognise that there is often something in between. This can lead to “splitting,” a term used in psychiatry to describe the inability to hold opposing thoughts, feelings, or beliefs and an inability to maintain a cohesive set of beliefs about oneself and others.

Because of these extreme patterns of thinking, people with BPD are prone to slip from one side to the opposite side in their thinking.

Impulsive Behaviour

It is instability that best characterises BPD as a disorder. Individuals with BPD will often battle with feelings of inadequacy manifesting in unstable emotions and relationships and impulsive behaviour. Impulsive behaviours are those that are inappropriate in terms of scale or risk and can include risky driving, unsafe sex and substance abuse.

People with BPD are less likely to take into account the consequences of actions and even turn to detrimental behaviours such as excessive drinking as a means to cope. Critically, unlike compulsivity, people with BDP will not recognise that the behaviour is abnormal. They may be quick to lash out and will often not recognise how those emotions are unreasonable or excessive.

Intense but Unstable Relationships with Others

People with borderline personality disorder often have an intense fear of abandonment and experience instability in relationships – often engaging in frantic efforts to avoid rejection.

People with BPD often struggle with being alone, yet inappropriate outbursts of anger, impulsiveness and frequent mood swings can push people away, even if the person with BPD desperately wants to have loving and lasting relationships.

BPD in Young People and Teenagers

The symptoms of a personality disorder can be different for each person and can range from mild to severe but it usually emerges in adolescence and continues into adulthood.

BPD in adolescence can cause teenagers to experience difficulty connecting with others. This can lead to isolation and an increase in self-destructive behaviours such as self-harm or suicidal ideation.

The heightened intensity of emotions and new situations that all teenagers have to deal with combined with an unstable sense of Self causes many teenagers with BPD to feel very chaotic and stressed. As a result, scenarios that should be relatively easy to manage, such as travel or schoolwork can become incredibly difficult.

Signs of BPD in Teenagers

The teenage years are undeniably challenging, young people go through many changes, including social changes and hormonal mood swings.

Hormones and development can cause teens to act in erratic ways that may seem out of character. Fluctuating actions, thoughts, and feelings are all normal parts of growing up, but the intensity of these feelings and the power to manage them is not the same for everyone. Some teens may feel completely overwhelmed by their emotions and feel unable to control their actions or feel comfortable in social situations.

It’s important to be able to identify the difference between “typical” teen behaviours and signs of a mental health condition, such as BPD. Knowing the signs of when a young person may need help is important as in most teenagers, BPD is successfully treated when can be caught early. Although BPD is generally viewed as a life-long disorder, early treatment of teenage BPD leads to a better long-term outcome in most cases.

There are a range of signs of borderline or emerging borderline personality disorder to look out for in teenagers, including:

  • Emotional reactions that may seem inappropriate and disproportional.

  • Damaged or fluid self-identity, poor self-esteem (seeing yourself as bad or unworthy) or distorted self-image, regular changes in self-identity and unstable self-image that includes shifting goals and values.

  • Inability to connect with others, or empathise with them, and exhibiting behaviour that seems narcissistic.

  • An intense fear of abandonment and rejection.

  • Eating disorders or distorted body image.

  • Volatile mood swings including intense anger and self-hatred.

  • Use of substances or ‘self-medication’ as a coping mechanism.

  • Periods of stress-related paranoia, anxiety and loss of contact with reality, lasting from a few minutes to a few hours.

  • Self-destructive patterns of behaviour and impulsive behaviour.

  • Self-harm, self-mutilating behaviour and suicidal behaviour; suicide attempts.

Causes of Borderline Personality Disorder (BPD)

As with a number of mental health disorders, what causes borderline personality disorder is not fully understood. However, there are a number of factors that may contribute to a diagnosis of BPD.


Recent studies have suggested a genetic predisposition for the disorder with borderline personality disorder being five times more common with a previous BPD diagnosis in the family.

Traumatic History

People diagnosed with BPD often have a history of childhood trauma. This trauma often includes physical abuse, sexual abuse, extreme stress, and abandonment during childhood. Early exposure to volatile relationships and conflicts also are also risk factors for individuals to develop BPD.


BPD patients do not have the neural capacity to hold negative emotions. Therefore, in people with BDP, the section of the brain that regulates emotions and controls impulses is often damaged. The neurobiological response to chronic stress is a possible cause. Chronic stress exposure and an overactive stress response can change brain structure and cause heightened concentrations of certain chemicals. These changes may affect the processing and integration of emotions and thoughts.

Borderline Personality Disorder Symptoms in Young People

When to Talk to a Mental Health Professional

Personality disorders are surrounded by myths and misinformation. Treating borderline personality disorder as early as possible leads to better long-term outcomes. With appropriate support and treatment from mental health professionals as well as support from loved ones, people with BPD symptoms are able to overcome their inability to manage their own emotions and destructive behaviours. You can also read more about related mental health conditions in our blog Bipolar vs Borderline Personality Disorder

Borderline Personality Disorder Diagnosis and Treatment

Borderline personality disorder can often be mistaken for other disorders, making accurate diagnosis challenging. The BPD symptoms listed in the Diagnostic and Statistical Manual of Mental Disorders DSM-5 diagnostic criteria are the same for teenagers and adults; however, some argue that symptoms are different in teenagers.

In order to diagnose BPD in teens, psychiatrists and doctors assess not only the individual’s behaviour but also their motivations for those behaviours. 

Dialectical behavioural therapy (DBT) is an evidence-based treatment for borderline personality disorder. In DBT a mental health professional teaches patients a variety of skills to manage their emotions and stop harming themselves. It is given the name dialectical because the purpose is to learn to balance two concepts that appear to be opposites: the need for acceptance and the need for change. 

DBT is often combined with other treatments such as cognitive-behavioural therapy (CBT) to help young people get the most out of each treatment session and work towards better controlling their emotions, stop self-harming behaviours, and have an easier time managing their feelings. Another effective treatment for BPD is cognitive-behavioural therapy (CBT)

There is currently no medication for treating BPD; however, there is medication to treat BPD symptoms such as anxiety and other mental health disorders that may be present alongside BPD.

Family participation is often encouraged as a key part of the treatment process. The family members of a young adult diagnosed with BPD may struggle to understand and accept the person diagnosed with BPD, so it is a chance to show their care, love and acceptance of the young person while learning more about the disorder.

If you’d like to learn more about similar topics, you can read our blog How to Spot The Signs of a Covert Narcissist.

Fiona - The Wave Clinic

Fiona Yassin is the founder and clinical director at The Wave Clinic. She is a U.K. and International registered Psychotherapist and Accredited Clinical Supervisor (U.K. and UNCG).

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