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Table 3 Pearson and Point-Biserial Correlations Between Group, Mediating and Outcome Variables

From: Potential mechanisms underlying sleep disturbance in young people with borderline personality disorder features: an exploratory study

  DASS DERS Group
Depression Anxiety Stress Non-Accept Goals Impulse Aware Strategies Clarity DERS Total 0 = HC, 1 = BPD
Insomnia Severity Index .723** .776** .745** .512** .562** .735** .486** .758** .633** .725** .720**
Pittsburgh Sleep Quality Index .648** .705** .656** .433** .508** .675** .441** .663** .568** .646** .617**
Epworth Sleepiness Scale .085 .172 .184 .093 .099 .066 .224 .061 .081 .111 .056
Bedtime −.206 −.126 .021 −.030 − .030 − .072 − .166 − .114 −.167 − .103 − .072
Rise Time .214 .282* .369** .365** .259* .294* .309** .290* .258* .351** .372**
Time in Bed .455** .450** .398** .445** .325** .407** .520** .445** .462** .503** .497**
Total Sleep Time .383** .354** .308** .297* .267* .307* .364** .380** .362** .386** .261**
Sleep Onset Latency −.025 −.009 −.014 .119 −0.003 .050 .022 −.009 .008 .051 .107
Sleep Efficiency .048 .007 .006 −.063 .025 .010 −.054 .062 .016 .008 −.020
Wake After Sleep Onset .015 .055 .057 .126 .014 .060 .156 −.001 .055 .069 .104
Bedtime (SD) .351** .442** .426** .211 .199 .303* .035 .371** .230 .297* .345**
Rise Time (SD) .331** .351** .343** .266* .315** .279* .044 .318** .166 .308* .394**
Time in Bed (CV) .118 .158 .190 .123 .171 .049 −.038 .120 −.030 .086 .125
Total Sleep Time (CV) .062 .112 .132 .136 .096 .007 −.020 .046 −.025 .045 .047
Group (0 = HC, 1 = BPD) .833** .795** .782** .648** .666** .869** .524** .874** .755** .880**
  1. Note. All values represent Pearson correlation co-efficient, except for correlations involving Group where Point-Biserial correlations are presented instead given the categorical nature of the Group variable. DASS Depression Anxiety Stress Scale. DERS Difficulties in Emotion Regulation Scale. HC Healthy comparison. BPD Borderline personality disorder. SD Standard deviation. CV Coefficient of variation * p < .05. ** p < .01