Psychological, social and pharmacological prevention and interventions for young people with emerging, subthreshold or diagnosed personality disorders: A systematic review.

Despite increasing recognition of personality disorder traits in adolescence, there is currently no systematic review that synthesises evidence across all intervention types and across the full spectrum of personality disorders in young people. This systematic review aims to describe existing psychological, psychosocial and pharmacological prevention and interventions for young people with PDs. Medline, Embase, PsycINFO, and Web of Science were used to retrieve studies. Effective Public Health Practice Project and Critical Skills Appraisal tools was used to assess risk of bias. Studies were included if they examined a prevention or intervention for individuals up to and including the age of 25 years with a PD. Findings were analysed using a narrative synthesis. Overall, forty-three studies were included. Thirteen studies evaluated Dialectical Behaviour Therapy, mostly for borderline PD (BPD), with six reporting significant symptom reductions (p < 0.01). Findings for self-harm and suicidal ideation were mixed. Mentalisation Based Therapy was examined in nine studies, with some evidence of reduced BPD symptoms and self-harm. Interventions such as Metacognitive Interpersonal Therapy (Group)-, Cognitive Analytic Therapy, and Emotion Regulation Training showed promising but inconsistent results. Two randomised controlled trials of omega-3 fatty acids and one of intranasal oxytocin suggested potential benefits, though evidence remains limited. This review suggests that future research should focus on investigating preventions and interventions for dimensional, rather than categorical, forms of PDs in young people. Randomised controlled trials are needed to establish a more robust evidence base for effective treatments.