Skip to main content Accessibility help

Mental capacity and borderline personality disorder

  • Karyn Ayre (a1), Gareth S. Owen (a2) and Paul Moran (a3)


The use of the Mental Capacity Act 2005 in assessing decision-making capacity in patients with borderline personality disorder (BPD) is inconsistent. We believe this may stem from persisting confusion regarding the nosological status of personality disorder and also a failure to recognise the fact that emotional dysregulation and characteristic psychodynamic abnormalities may cause substantial difficulties in using and weighing information. Clearer consensus on these issues is required in order to provide consistent patient care and reduce uncertainty for clinicians in what are often emergency and high-stakes clinical scenarios.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the or variations. ‘’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Mental capacity and borderline personality disorder
      Available formats

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Mental capacity and borderline personality disorder
      Available formats

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Mental capacity and borderline personality disorder
      Available formats


This is an open-access article published by the Royal College of Psychiatrists and distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Corresponding author

Correspondence to Karyn Ayre (


Hide All

Declaration of interest




Hide All
1 National Institute for Health and Care Excellence. Borderline Personality Disorder: Treatment and Management (CG78). NICE, 2009.
2 Zimmerman, M, Mattia, JI. Axis I diagnostic comorbidity and borderline personality disorder. Compr Psychiatry 1999; 40: 245–52.
3 Skodol, AE, Gunderson, JG, McGlashan, TH, Dyck, IR, Stout, RL, Bender, DS, et al. Functional impairment in patients with schizotypal, borderline, avoidant, or obsessive-compulsive personality disorder. Am J Psychiatry 2002; 159: 276–83.
4 Bender, DS, Dolan, RT, Skodol, AE, Sanislow, CA, Dyck, IR, McGlashan, TH, et al. Treatment utilization by patients with personality disorders. Am J Psychiatry 2001; 158: 295302.
5 Fok, ML, Hayes, RD, Chang, CK, Stewart, R, Callard, FJ, Moran, P. Life expectancy at birth and all-cause mortality among people with personality disorder. J Psychosom Res 2012; 73: 104–7.
6 Klonsky, ED. The functions of deliberate self-injury: a review of the evidence. Clin Psychol Rev 2007; 27: 226–39.
7 Szmukler, G. ‘Personality disorder’ and capacity to make treatment decisions. J Med Ethics 2009; 35: 647–50.
8 David, AS, Hotopf, H, Moran, P, Owen, G, Szmukler, G, Richardson, G. Mentally disordered or lacking capacity? Lessons for management of serious deliberate self harm. BMJ 2010; 341: c4489.
9 Kendell, RE. The distinction between personality disorder and mental illness. Br J Psychiatry 2002; 180: 110–5.
10 Winburn, E, Mullen, R. Personality disorder and competence to refuse treatment. J Med Ethics 2008; 34: 715–6.
11 Department for Constitutional Affairs. Mental Capacity Act 2005 Code of Practice. TSO (The Stationery Office), 2007.
12 Gunderson, JG, Stout, RL, McGlashan, TH, Shea, MT, Morey, LC, Grilo, CM, et al. Ten-year course of borderline personality disorder: psychopathology and function from the Collaborative Longitudinal Personality Disorders study. Arch Gen Psychiatry 2011; 68: 827–37.
13 Mak, ADP, Lam, LCW. Neurocognitive profiles of people with borderline personality disorder. Curr Opin Psychiatry 2013; 26: 90–6.
14 Ruocco, AC, Amirthavasagam, S, Choi-Kain, LW, McMain, SF. Neural correlates of negative emotionality in borderline personality disorder: an activation-likelihood-estimation meta-analysis. Biol Psychiatry 2013; 73: 153–60.
15 Stoffers, JM, Vollm, BA, Rucker, G, Timmer, A, Huband, N, Lieb, K. Psychological therapies for people with borderline personality disorder. Cochrane Database Syst Rev 2012; 8: CD005652.
16 Parsons, T. The Social System. The Free Press of Glencoe, 1951.
17 Frank, AW. From sick role to practices of health and illness. Med Educ 2013; 47: 1825.
18 Lewis, G, Appleby, L. Personality disorder: the patients psychiatrists dislike. Br J Psychiatry 1988; 153: 44–9.
19 Pickard, H. Responsibility without blame: empathy and the effective treatment of personality disorder. Philos Psychiatr Psychol 2011; 18: 209–23.
20 Fuchs, T. Fragmented selves: temporality and identity in borderline personality disorder. Psychopathology 2007; 40: 379–87.
21 Hindmarch, T, Hotopf, M, Owen, GS. Depression and decision-making capacity for treatment or research: a systematic review. BMC Medical Ethics 2013; 14: 54.
22 Elliot, C. Caring about risks. Are severely depressed patients competent to consent to research? Arch Gen Psychiatry 1997; 54: 113–6.
23 Drapeau, M, Perry, CJ, Körner, A. Interpersonal patterns in borderline personality disorder. J Pers Disord 2012; 26: 583–92.
24 B vs Croydon Health Authority (1995) Fam 133.
25 Goodman, M, Roiff, T, Oakes, AH, Paris, J. Suicidal risk and management in borderline personality disorder. Curr Psychiatry Rep 2012; 14: 7985.
26 Krawitz, R, Batcheler, M. Borderline personality disorder: a pilot survey about clinician views on defensive practice. Australas Psychiatry 2006; 14: 320–2.
27 Re M; ITW v Z and M [2009] EWHC 2525 (Fam).
28 Buchanan, A. Mental capacity, legal competence and consent to treatment. J R Soc Med 2004; 97: 415–20.
29 Re T (Adult: Refusal of Treatment) [1992] 4 All ER 649 at 669.

Mental capacity and borderline personality disorder

  • Karyn Ayre (a1), Gareth S. Owen (a2) and Paul Moran (a3)


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.

Mental capacity and borderline personality disorder

  • Karyn Ayre (a1), Gareth S. Owen (a2) and Paul Moran (a3)
Submit a response


Capacity assessments- diagnosis is misleading

Graham M Behr, Consultant Psychiatrist, CNWL Foundation NHS Trust
19 February 2017

Ayre et al (1) attempt to support the usefulness of the assessment of capacity in Borderline Personality Disorder by validating it as a diagnostic construct. This is a flawed approach for these reasons:

•People with a ‘diagnosis ‘can move in and out of states of competence as much as those of us without a diagnosis. What would the Mental Capacity Act (MCA) have to say about a newly bereaved mother with suicidal thoughts (other than require us to invent a disorder of mind for her)?

•Acute presentations frequently preclude the ability to make a diagnosis. States of distress, psychoactive substances, lack of information etc. all cloud our ability to make clear assessments. Assessors vary in experience and competence, and judgements about diagnosis vary amongst even those with comparable experience and skill.

•Because the MCA and popular culture privileges the place of diagnosis in determinations of responsibility, this directs clinicians to first make a diagnosis and then, secondarily, to make a determination of capacity. This has the effect of predetermining capacity judgements based on diagnosis.

•Co-morbidity is a frequent finding in personality disorder. However the presence of ‘Axis I’ disorder has the effect of ‘trumping’ the Axis II in the minds of professionals, the public and, crucially, in patients themselves, colouring their own expectations of their ability to assume personal responsibility.

•Finally there is an issue of tautology. Capacity could not be impaired without some impairment of our cognitive, perceptual or emotional state - the very abnormalities which describe disorder of mind. The absence of capacity is thus sufficient to denote a disorder of mind and the requirement to ‘name’ this directs clinicians to assign a diagnosis and attribute the incapacity to the diagnosis rather than the aspect of function which impairs their capacity.

It follows that we should be arguing to dissociate mental capacity from ‘disorder of mind’ and, instead, deepen our thinking, as their article attempts to do, about the application of capacity judgements in clinical situations.


1 Ayre K, Owen G.S, Moran P. Mental Capacity and Borderline Personality Disorder. BJPsych Bull 2017; 41:33-36

... More

Conflict of interest: None Declared

Write a reply

Capacity in Crisis

Eugene G Breen, Consultant Psychiatrist, Mater Misericordiae University Hospital, Dublin
07 February 2017

The paper by Ayre et al highlighting the conundrums related to capacity assessment in BPD is enlightening. 1 In general it could be expanded to all cases of deliberate self-harm presenting in accident and emergency departments. It is impossible for clinicians to establish beyond reasonable doubt that a person in crisis has capacity to make healthcare-related decisions. BPD in particular has a track record of affective lability with concomitant erroneous judgement and distorted cognitions.

There is an established literature on the relationship between stress and interpersonal friction, and faulty decision-making in airplane crews, surgical theatres, and soccer teams. 2,3,4,6 The timeframe of behaviour should be consistent over several months at a minimum to satisfy a capacity assessment. The Medical Protection Society database shows clearly that team friction and expressed emotion contort and disturb judgement and decision-making capacity with resultant harm to patients.5 If this level of distress impairs judgement in doctors it suggests that a crisis or mental illness - be it BPD or depression - are even more likely to cause impairment of judgment and decision-making capacity.

There are multiple confounding factors that may contribute to incapacity during a mental health crisis, including mood disturbance, heightened stress, other psychiatric or medical illness, psychoactive effects of medication or drugs of abuse, social stressors and life events, and the absence of a period of stability. It is therefore evident that assessing capacity in the middle of a crisis is unsafe and, in fact, impossible.

Consequently, it is my view that intervention is always indicated in a life or death situation, because the likelihood is that the patient lacks capacity at that moment to make a capacitous decision. It also puts medical staff in an impossible situation, trying to weigh up decisional capacity in a person who couldn’t possibly have capacity given the acute crisis. There should be a covering clause in all ethical and legal medical policies exonerating staff from litigation whilst doing what is best in the situation, i.e. treating the patient. This would eliminate the confusion and conflicting opinions in the acute situation. Paracetamol overdose is the classic example. I thank Drs Ayre, Owen, and Moran for their contribution to this important area.

1.Ayre K, Owen GS, Moran P. Mental capacity and borderline personality disorder. BJPsych Bull 2017; 41.1: 33-36.

2.DeHart J. Asiana Airlines crash. A cockpit culture problem? The Diplomat 2013; July 16.

3.Leonard M. Ghaham S, Bonacum D. The human factor; the critical importance of effective team work and communication in providing safe care. Qual Saf Health Care 2004; 13: 85-90.

4.Mello AL, Delise LA. Cognitive diversity to team outcomes.The roles of cohesion and conflict management. Small Group Research 2015; 46: 204-226.

5.Mastering Professional Interactions. Medical Protection Society. Workshop 2010.

6.Flin R. Rudeness at work. BMJ 2010; 340: c2480.

... More

Conflict of interest: None Declared

Write a reply


Reply to: Submit a response

Your details

Conflicting interests

Do you have any conflicting interests? *