Borderline Personality Disorder (BPD) is associated with increased levels of suicide ideation, as well as being highly comorbid with depression. Nonetheless, research on sleep characteristics and...Show moreBorderline Personality Disorder (BPD) is associated with increased levels of suicide ideation, as well as being highly comorbid with depression. Nonetheless, research on sleep characteristics and suicidality in personality psychopathology remains understudied. Hence, this study analyzed the connection between BPD, eveningness chronotype (i.e. delayed sleep-wake pattern), depression and suicide ideation. It was expected that eveningness would significantly elevate suicide risk in the BPD population and that depression would control for some of the variance but not hinder the moderation of eveningness. This research drew upon data from the Netherlands Study of Depression and Anxiety (NESDA). A subset of 1713 eligible participants was selected, among whom 246 were diagnosed with BPD. Questionnaires included the Personality Disorder Questionnaire (PDQ4+), the Munich Chronotype Questionnaire (MCTQ), the Beck Suicidal Ideation questionnaire (BSI) and the Composite Interview Diagnostic Instrument (CIDI). Multiple tests were conducted, such as linear regressions and two simple moderation analyzes using the PROCESS extension by Hayes. Results demonstrated that: (a) BPD significantly predicted suicide ideation (b = .62, p < .001); (b) eveningness did not significantly moderate the relation between BPD and suicide ideation; (c) eveningness did not significantly predict suicide ideation with or without controlling for depression; and lastly (d) depression contributed to the explained variance in the elevation of suicide ideation (b = .67, p < .001). To explore the impact of sleep disturbances on suicide ideation, future research should focus on Delayed Sleep Wake Phase Disorder (DSWPD) and insomnia since they have been both linked to BPD, eveningness and suicide ideation.Show less