Borderline Personality Disorder (BPD) is a complex mental health condition that affects how someone thinks, feels and interacts with others. Getting a diagnosis can be a turning point – not just for treatment but also for making sense of past struggles.
In this post, we’ll walk you through what the process of diagnosing BPD usually looks like. Whether you’re seeking help for yourself or supporting someone else, knowing what to expect can make things feel a little less overwhelming.
Table of Contents:
A reminder: What is BPD?
Before diving into the diagnosis process, it helps to understand what BPD is. Borderline Personality Disorder is characterised by intense emotional experiences, difficulty managing relationships, fear of abandonment and a shifting sense of self. Other symptoms can include impulsive behaviour, mood swings, chronic feelings of emptiness and, in some cases, self-harm or suicidal thoughts.
It’s not uncommon for people with BPD to feel misunderstood or misdiagnosed. That’s why a proper assessment is so important – not just to tick boxes, but to gain insight and get the right kind of support.
When to seek help
If you or someone you care about has been struggling with emotional instability, relationship difficulties, impulsivity or patterns of self-sabotage, it’s worth talking to a mental health professional. Often, people seek help after reaching a breaking point, but early support can really help prevent things from escalating.
It’s important to remember: seeking a diagnosis isn’t about getting a label. It’s about understanding your mental health and finding tools to manage it.
Step 1: Talking to your GP
The first step for most people in the UK is to book an appointment with a GP. This can feel daunting, but GPs are trained to help you take that first step. Be as open and honest as you can about what you’ve been experiencing – emotionally, mentally and in your relationships.
Tips for your GP appointment
- Write down symptoms: Especially if they’ve been going on for a while. Include mood swings, emotional reactions, struggles with identity, impulsive actions or self-harm.
- Mention patterns: BPD tends to show up in long-standing patterns rather than one-off events.
- Be specific: If certain symptoms are affecting your work, studies or relationships, say so.
Your GP may refer you to a mental health service – either a local NHS community team or a specialist personality disorder service if one is available in your area.
Step 2: Referral to a mental health professional
Once referred, you might be seen by a psychologist, psychiatrist or community mental health worker. The wait can vary depending on your local area, but don’t lose hope – this step is key for getting the right support.
What professionals look for
Mental health professionals use diagnostic criteria to identify BPD, usually based on the ICD-11 (used by the NHS) or the DSM-5 (more common in research or international settings). You don’t need to know these inside out, but they help structure the process.
To be diagnosed with BPD, a person usually needs to meet several criteria, such as:
- Persistent instability in emotions and self-image
- Intense and unstable relationships
- Efforts to avoid abandonment
- Impulsive or self-damaging behaviours
- Recurrent suicidal behaviours or self-harm
- Chronic emptiness or feelings of disconnection
- Intense anger or difficulty controlling it
- Stress-related paranoia or dissociation
These symptoms need to have been present over time and across different areas of life – not just in one situation.
Step 3: The assessment
This is where the actual diagnostic process begins in earnest. It’s usually done through one or more in-depth interviews. Some services also use questionnaires or structured tools.
What to Expect in an Assessment
- Background history: Your early life, family dynamics and past mental health experiences
- Current issues: How you’re feeling now, what’s triggered the need for support
- Relationship patterns: How you interact with others, any recurring difficulties
- Emotional regulation: How you manage intense feelings and what coping mechanisms you use
- Sense of self: Whether you feel like you have a stable identity or if it shifts often
It’s important to be as honest as possible, even if it’s hard. You won’t be judged. These professionals are here to help you make sense of things, not to criticise or shame you.
Some people find assessments exhausting or emotional – and that’s completely normal. Take your time and ask for breaks if you need them.
Step 4: Ruling out other conditions
BPD can sometimes be confused with other mental health issues, like bipolar disorder, complex PTSD or ADHD. It’s also common for people to have more than one diagnosis.
Your assessor will try to get a clear picture by:
- Looking at when symptoms started
- Noting how long they’ve lasted
- Exploring how they affect different areas of life
- Asking about trauma, substance use or physical health conditions
This process helps ensure that BPD is the right diagnosis – or whether something else might better explain what’s going on.
Step 5: Getting the diagnosis
If the professional believes your symptoms fit the criteria, they’ll talk you through the diagnosis. This can be a powerful moment – for some, it brings a sense of clarity, relief or validation. For others, it might feel scary, stigmatising or confusing.
It’s okay to have mixed feelings
Being told you have a personality disorder can feel heavy. But remember – this doesn’t define you. A diagnosis is a tool, not a verdict. It opens doors to treatment, support and better understanding.
If you’re unsure how to feel about it, talk to your clinician. You can ask:
- Why do you think this is the right diagnosis?
- What support or treatment is available?
- How can I explain this to others if I choose to?
Step 6: After the diagnosis
Once diagnosed, you should be offered a treatment plan. This might include:
- Talking therapies: The gold standard for BPD is Dialectical Behaviour Therapy (DBT), but other approaches like Mentalisation-Based Therapy (MBT) or Schema Therapy can also help.
- Medication: While there’s no drug that treats BPD directly, medication might be prescribed for symptoms like anxiety, depression or sleep issues.
- Crisis planning: If self-harm or suicidal thoughts are part of your experience, your team will help you develop a plan to stay safe and access support quickly.
- Peer support: Connecting with others who have lived experience can be incredibly validating and helpful.
Not every area offers the same resources, so your treatment path may vary. If something isn’t offered locally, ask your care team about alternatives or self-referral options.
What if you’re not diagnosed?
Sometimes, people go through the assessment process and are told they don’t meet the full criteria for BPD. This doesn’t mean your struggles aren’t valid.
In these cases, professionals might suggest other ways to understand your experience, like traits of BPD, complex trauma, anxiety or mood disorders. Either way, the goal is the same: getting you the right help.
Final thoughts: Diagnosing BPD
Getting diagnosed with BPD can feel like stepping into a new chapter – one where things finally start making sense. The process isn’t always quick or easy, but it’s worth it. It opens the door to targeted support, greater self-understanding and, with time, healing.
If you’re on this journey, be kind to yourself. You’re not alone, and support is out there. Diagnosis is just the beginning – not the end of your story.
