Are mood stabilisers helpful in treatment of borderline personality disorder?

Borderline personality disorder is a severe mental health problem that affects around 1% of people.1 It is characterised by intense unstable relationships, impulsivity, and chronic feelings of emptiness.2 Affective instability is also a core symptom, with marked fluctuations in mood, which may switch rapidly from hopelessness and despair to feeling irritable, angry, and out of control. People with this condition have high rates of deliberate self harm and a rate of suicide that is 20 times that of the general population.3 Although psychological treatments have been shown to improve the mental health of people with borderline personality disorder,4 many people do not engage with such treatments, and as many as half of those who do engage drop out before treatment has been completed.5

People with borderline personality disorder are more likely to experience mood disorders, including bipolar affective disorder.6 7 Differentiating between borderline personality disorder and bipolar affective disorder can be difficult. Changes in mood are much more frequent among people with borderline personality disorder, and such patients are more likely to report feelings of anger, in contrast to elated mood reported by people with bipolar disorder.8

Affective instability among people with borderline personality disorder has led to interest in the role of mood stabilisers (sodium valproate, lamotrigine, topiramate, carbamazepine, and lithium) as a potential treatment. However, the evidence base for the use of these drugs in people with this condition is poor, and considerable uncertainty exists about whether they should be used in clinical practice. Current guidance from the National Institute for Health and Care Excellence (NICE) states that drug treatments should “not be used for borderline personality disorder or for the individual symptoms or behaviour associated with the disorder.”9 By contrast, American guidelines state that mood stabilisers should be considered …