Non-suicidal self-injury as an emotion regulation strategy in borderline personality disorder: relationship with affect dysregulation severity

Introduction: Borderline personality disorder is the psychiatric condition most strongly associated with non-suicidal self-injury, with a lifetime prevalence of 65-80% in clinical samples. Defined as the deliberate damage of body tissue without suicidal intent, this behaviour is conceptualised within Linehan’s biosocial theory as a strategy for reducing aversive internal states such as anger, emptiness and dissociation through immediate emotional relief. A 2018 meta-analysis confirmed that emotion regulation is the most prevalent function of non-suicidal self-injury, endorsed by 63-78% of individuals with borderline personality disorder. Despite the strength of this link, reported effect sizes vary considerably across studies, reflecting heterogeneity in measurement instruments and adjustment for confounders such as depression severity and trauma load. Affect dysregulation, defined as difficulty modulating the intensity, duration or expression of emotional states, is widely cited as the proximal mechanism, yet its specific dimensions remain unevenly characterised.

Aim: To provide a clear, data-driven synthesis of the association between affect dysregulation, measured with the Difficulties in Emotion Regulation Scale (DERS), and non-suicidal self-injury in adults with borderline personality disorder.

Methods: Six databases were searched: MEDLINE, Embase, PsycINFO, Web of Science, Cochrane and Scopus. Eligible studies were peer-reviewed, used adult clinical samples diagnosed with borderline personality disorder according to DSM-5 criteria, included validated measures of non-suicidal self-injury and the DERS, and reported quantitative data on the association between the two. Pooled estimates from existing meta-analyses were extracted alongside individual study findings.

Results: A 2019 meta-analysis (48 publications, 49 independent samples) reported a pooled odds ratio of 3.03 (95% CI 2.56-3.59) for the association between emotion dysregulation and non-suicidal self-injury, remaining significant at 2.40 (95% CI 2.01-2.86) after adjustment for publication bias. Among DERS subscales, limited access to emotion regulation strategies showed the strongest association with self-injury (OR 3.89, 95% CI 2.44-6.23). Non-acceptance of emotional responses, impulse control difficulties and difficulties engaging in goal-directed behaviour produced moderate-to-strong effects. Lack of emotional awareness yielded the weakest association (OR 1.53, 95% CI 1.25-1.88). A 2026 clinical study (184 emerging adults, 44 with borderline personality disorder) identified the DERS impulse, awareness and clarity subscales as the strongest discriminators of the diagnosis (OR 5.91, 3.56 and 2.90 respectively), with a total DERS score above 129 increasing the odds of meeting criteria for borderline personality disorder twelvefold. Recent self-injury was associated with greater dysregulation than past self-injury (OR 1.68, 95% CI 1.03-2.73).

Conclusions: Affect dysregulation is consistently associated with non-suicidal self-injury in borderline personality disorder, with the strongest signal coming from limited access to adaptive coping strategies and impaired impulse control. Brief screening with the DERS could identify a substantial proportion of high-risk patients, supporting timely allocation of dialectical behaviour therapy modules focused on emotion regulation and impulse-control training. Future longitudinal studies should test whether targeted reduction of affect dysregulation lowers the recurrence of self-injurious behaviour.

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