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Table 6 Mean differences, standard deviation, t-scores (paired), p-values, effect size d and its interpretation between the accumulated days with (17) and without NSSI (172) of our ten participants who have shown NSSI regarding the imagery characteristics, affect, and entrapment beliefs in the diary

From: Mental images, entrapment and affect in young adults meeting criteria of nonsuicidal self-injury disorder (NSSID) – a daily diary study

 Mean difference NSSI-days, noNSSI-days (SD)tpadbInterpretation
Compellingness.90 (1.79)
Vividness−.47 (2.45)−.61.56−.29Small
Controllability−1.14 (1.84)−1.97.08†−.89Large
Nowness−.03 (1.69)1.55.96−.02
Distress−.16 (1.58)−.32.75−.09
Comfort1.14 (2.33)
Daily positive affect−.30 (.41)−2.26.05†.50Medium
Daily negative affect.62 (.94)2.08.07†.74Medium
Positive affect after image.17 (.68).78.45.24Small
Negative affect after image.26 (.90).90.39.28Small
Entrapment.51 (1.13)
  1. alevel of significance: †: p < .10
  2. bregarding the effect size, we first obtained the dz for paired t-tests which, however, overestimates the effect size compared to independent groups and should therefore be adjusted (e.g., [67]), and therefore obtained the dav according to Cumming [68]