Principlism is the dominant ethical theory in modern medicine. Autonomy is ‘king’ of the principles espoused and operationalised in consent. Consent is the mechanism by which all medical interactions occur. In borderline personality disorder (BPD) there is often a diffuse sense of self, emotional instability and impulsivity that can lead to medically dangerous non-suicidal self-injury, acute medical intervention and then a withdrawal of consent while the potential threat to the person's well-being remains high. Claims of lack of capacity lack veracity, and simply acting against the patient's will may be illegal. Understanding the will and preferences of patients is a step forward, but it is not always possible in time-sensitive situations. A cautious paternalism is therefore warranted both to ensure the patient's well-being while being honest as to the reasons for this, and to possibly build epistemic trust between the medical system and the patient with BPD.
