Clinical predictors of insomnia in borderline personality disorder: a polysomnographic and subjective examination.

Background: Sleep disturbances are common in patients with borderline personality disorder (BPD) and are associated with a poor prognosis and symptom severity. Research findings on sleep abnormalities in individuals with BPD have been inconsistent, with limited evidence linking subjective and objective measures.

Methods: We compared 44 women with BPD with 41 healthy controls. We examined differences (using ANCOVAs and ordinal logistic regression) and associations (using correlations) between objective sleep assessment (polysomnography) and subjective measures (Consensus Sleep Diary, Insomnia Severity Index, Pittsburgh Sleep Quality Index). We explored predictors of insomnia in BPD patients, including BPD severity, symptomatology, comorbid conditions, and medication use, via standard least squares regressions and ANOVAs.

Results: A total of 22% of patients with BPD had clinically significant insomnia (cut-off ≥ 15), 85% reported mild (subthreshold) insomnia (cut-off > 10) (Insomnia Severity Index; ISI), and 94% reported sleep quality disturbances (PSQI > 5). Compared with those in HC, PSG results in individuals with BPD revealed a longer duration in bed, longer sleep period, REM latency, wake after sleep onset latency, Stage N1 sleep duration, shorter N2 sleep duration, and, with age, more arousals and awakenings. The correlations between objective and subjective sleep measures were weak in both groups. In patients with BPD, a greater degree of insomnia predicted a reduction in total sleep time and increased awakenings and arousals on PSG. Clinical BPD severity, emotional reactivity and dysregulation, depression symptoms, posttraumatic stress symptoms, alexithymia, and presleep arousal were associated with greater insomnia in BPD patients.

Conclusions: Our study confirmed high rates of insomnia and sleep disturbances in individuals with BPD, which contrasted with relatively minor PSG alterations. Clinical BPD severity and symptomatology are associated with sleep abnormalities in individuals with BPD. Insomnia is a neglected yet important characteristic of the BPD phenotype, warranting more attention in future research and clinical guidelines.