Phone numbers
Treatment enquiries: 0800 840 3219
General enquiries: 0800 138 8680
Make an Enquiry

Diagnosing Borderline Personality or Bipolar Disorder?

Welcome to Priory Bitesize, your monthly e-bulletin in which a mental health expert will discuss dealing with certain conditions to support your patient discussions.

This month, Dr Judith Mohring (MBBS, MRCPsych, MA, CCST), Consultant Psychiatrist at Priory Wellbeing Centre Fenchurch Street in London, talks about the challenges in diagnosing borderline personality disorder (BPD) and bipolar disorder.

A common question asked by GPs is whether a patient has BPD or bipolar disorder.

Having worked in a specialist BPD service and having set up a service in Holloway prison for women who self-harm, it was a question I felt reasonably confident to approach.

Despite this, teasing out different symptoms and making a clear diagnosis takes time and is complex. Changes in the understanding and description of bipolar disorder have added to this complexity. A thorough assessment by a specialist in general adult psychiatry can be enormously helpful to patients and GPs in guiding further treatment.

This article focuses on the diagnosis of the two conditions including:

  • Controversy over diagnosing BPD
  • The benefits of making a distinction between personality and mood disorder
  • The core features of BPD
  • The core features of bipolar disorder
  • Distinguishing between the features of each condition
  • A brief overview of treatment options for each condition

Controversy over diagnosing BPD

During my early training, I was told that we should not diagnose a personality disorder without having conducted a longitudinal assessment. There was resistance to label people as personality disordered because it was believed that:

  • The label was pejorative
  • Personality disorders don’t get better
  • There was no effective treatment

However, the evidence suggests the opposite is true.

BPD gets better with age and there is a range of therapy with a good evidence base. If there is still stigma, it lies with us as professionals. Patients generally welcome knowing why they feel as they do, and will often have researched their diagnosis on the internet prior to coming to see us.

The benefits of making a distinction between personality and mood disorder

Qualitatively, patients tell me they feel a sense of relief when they meet a specialist who is clear about what is going on and comfortable making a diagnosis.

I usually ask the patient what they think the problem is. Often they will say they suspect BPD. If the patient doesn’t find the label to be useful, I don’t use it. It is their experience and condition.

The advantages of a diagnosis include:

  1. It enables self-help
  2. It gives clear signposts for treatment
  3. It enables discussion of prognosis and outcomes

The core features of BPD

BPD has very specific symptoms, which makes it easy to distinguish from other conditions. It is common not to screen for the core features but to diagnose based on 'countertransference feeling'. This is particularly the case when people present with self-harming behaviour.

I was trained in DSM 4 which is a more user-friendly diagnostic tool than ICD 10 for BPD as it doesn’t subdivide it into two conditions.

The criteria for BPD in DSM 4

In addition to the core features of all personality disorders, the criterion are:

  1. Frantic efforts to avoid real or imagined abandonment
  2. A pattern of unstable and intense interpersonal relationships characterised by alternating between extremes of idealisation and devaluation
  3. Identity disturbance: markedly and persistently unstable self-image
  4. Impulsivity in at least two areas that are potentially self- damaging (e.g. spending, sex, substance abuse, reckless driving, binge eating). Note: Do not include suicidal or self-mutilating behaviour covered in Criterion 5
  5. Recurrent suicidal behaviour, gestures, or threats, or self-mutilating behaviour
  6. Affective instability due to a marked reactivity of mood (e.g. intense episodic dysphoria, irritability, or anxiety usually lasting a few hours and only rarely more than a few days)
  7. Chronic feelings of emptiness
  8. Inappropriate, intense anger (e.g. frequent displays of temper, constant anger, recurrent physical fights)
  9. Transient, stress-related paranoid ideation or severe dissociative symptoms

Someone must have five of these nine features to merit the full diagnosis.

Symptoms of BPD 

The mood swings of BPD have a particular character - they are abrupt and often occur without warning over a period of seconds or minutes. The patient experiences a 'state shift' from one emotional state to another. Often, this is rapid and unpleasant.

Clients can sometimes clearly describe their different self states e.g. numb, angry, self loathing and cut off. The different self states are not integrated into an overarching sense of self; they can be perceived as 'other' - the patient may not recognise themselves within each state.

State shifts cause a great deal of anxiety and can lead to dissociation - clients require an empathetic approach. In the DSM 5, anxiety is included as a core feature of BPD.

The core features of bipolar disorder

Effective diagnosis of mood disorder relies on taking a proper longitudinal mood history from adolescence with particular attention to any hypomanic episodes. This is where a specialist assessment is useful.

Bipolar I disorder

Bipolar I disorder involves one or more manic episodes or mixed (mania and depression) episodes. The episodes are not due to another medical condition or substance use.

Bipolar II disorder

Bipolar II disorder has one or more major depressive episodes with at least one hypomanic episode. There are no manic or mixed episodes.

A hypomanic episode is characterised by a distinct period of persistently elevated, expansive, or irritable mood, lasting throughout at least four days. It differs from a manic episode because:

  1. The mood usually isn’t severe enough to cause problems with the person working or socialising with others (e.g. they don’t have to take time off work during the episode), or to require hospitalisation
  2. There are never any psychotic features present in a hypomanic episode

Rapid-cycling bipolar disorder

At least four distinct mood episodes within a year. Rapid cycling affects more women than men, and appears to be more persistent in those who have their first bipolar episode at a young age.

Distinguishing between the features of each condition

  1. BPD has no mania, and is characterised by its own distinct features - see DSM 4
  2. Mood variability in BPD is over a period of minutes or hours, in the form of state shifts between emotions. Distinct mood episodes in bipolar last days or weeks
  3. Family history of one or other can be a guide as there is a genetic component to each
  4. Age at onset and natural history
  5. Bipolar disorder often presents later and worsens with age and recurrent episodes
  6. BPD often presents in adolescence and improves with age


Patients with BPD frequently have co-morbid mood disorders including depression and bipolar II. Suicidal behaviour can be a feature of a range of conditions and on its own does not suggest a particular diagnosis.

BPD is not always associated with childhood abuse or trauma. Diagnoses can change over time as presentations evolve.

Mixed affective states can be very hard to distinguish from BPD. A really good mood history is key to getting the diagnosis right.

A brief overview of treatment options

A thorough specialist assessment is essential to establish the diagnosis


  1. Pharmacotherapy tailored to the patient’s presenting symptoms. This may include antidepressants, mood stabilising antipsychotics like quetiapine or anxiolytics including pregabalin. Avoid drugs toxic in overdose and tailor treatment closely to response. Patients often require a case management approach.
  2. Psychotherapy with an evidence base. Dialectical behaviour therapy (DBT) is the treatment of choice and is a 16-24 week group and individual outpatient programme available through a number of Priory sites.

Bipolar disorder

  1. Bipolar depression - a mood stabilising antidepressant is required either as a single drug (quetiapine, olanzapine, lamotrigine) or as a combination (fluoxetine and olanzapine). Lithium may be required but should not be started in primary care. Avoid unopposed antidepressants. Beware of weight gain with olanzapine.
  2. Mania or hypomania - consider stopping any antidepressant. Start an antipsychotic such as quetiapine, olanzapine, haloperidol or risperidone.
  3. Consider referral to secondary care. Lithium or sodium valproate may be required. Sodium valproate should be avoided in women of child bearing age.
  4. Psychotherapy for bipolar disorder needs to come from a therapist experienced in the condition and could include cognitive behavioural therapy (CBT) for depression and relapse prevention, crisis planning and early intervention for mania.

This page was reviewed by Dr Judith Mohring (MBBS, MRCPsych, MA, CCST), Consultant Psychiatrist at Priory Wellbeing Centre Fenchurch Street

Get in Touch Today

For details of how Priory can provide you with assistance regarding mental health and wellbeing, please call 0800 840 3219 or click here to submit an enquiry form. For professionals looking to make a referral, please click here

Contact Us
Call our Enquiry Line
0800 840 3219
Can't find what you're looking for?
Contact us by phone: 0800 840 3219 or Make an Enquiry