A theoretical perspective on the role of sleep in borderline personality disorder: From causative factor to treatment target.

Sleep plays a crucial role in emotion regulation. Disturbed sleep is therefore increasingly seen as a potential causal factor for the development and maintenance of affective psychiatric disorders. This may hold especially for borderline personality disorder (BPD), a core emotion dysregulation disorder. Although BPD is strongly associated with sleep disturbances such as insomnia, nightmares and circadian dysrhythmia, research into the role of sleep in BPD remains sparse. In this narrative review, we outline a putative vicious cycle of reciprocal exacerbation of disturbed sleep and emotion dysregulation in BPD, that sheds light on BPD pathophysiology and opens up new avenues for sleep-based treatments. We discuss emotional dysregulation as the base of BPD as well as the observed sleep disturbances in BPD. Based on existing theories of sleep's role in emotion regulation and memory, we then propose several behavioral and neurobiological pathways by which inherent sleep disturbances in BPD may hamper adaptive overnight emotional processing. This likely results in sustained emotional states and associated sleep-disruptive behavior, which in turn negatively impact sleep. We end by proposing a sleep-based research agenda for BPD to further detail the causative role of disturbed sleep in BPD and test the effectiveness of novel sleep-based treatment strategies.