Mental ill‐health represents the main threat to the health, survival and future potential of young people around the world. There are indications that this is a rising tide of vulnerability and need for care, a trend that has been augmented by the COVID‐19 pandemic. It represents a global public health crisis, which not only demands a deep and sophisticated understanding of possible targets for prevention, but also urgent reform and investment in the provision of developmentally appropriate clinical care. Despite having the greatest level of need, and potential to benefit, adolescents and emerging adults have the worst access to timely and quality mental health care. How is this global crisis to be addressed? Since the start of the century, a range of co‐designed youth mental health strategies and innovations have emerged. These range from digital platforms, through to new models of primary care to new services for potentially severe mental illness, which must be locally adapted according to the availability of resources, workforce, cultural factors and health financing patterns. The fulcrum of this progress is the advent of broad‐spectrum, integrated primary youth mental health care services. They represent a blueprint and beach‐head for an overdue global system reform. While resources will vary across settings, the mental health needs of young people are largely universal, and underpin a set of fundamental principles and design features. These include establishing an accessible, “soft entry” youth primary care platform with digital support, where young people are valued and essential partners in the design, operation, management and evaluation of the service. Global progress achieved to date in implementing integrated youth mental health care has highlighted that these services are being accessed by young people with genuine and substantial mental health needs, that they are benefiting from them, and that both these young people and their families are highly satisfied with the services they receive. However, we are still at base camp and these primary care platforms need to be scaled up across the globe, complemented by prevention, digital platforms and, crucially, more specialized care for complex and persistent conditions, aligned to this transitional age range (from approximately 12 to 25 years). The rising tide of mental ill‐health in young people globally demands that this focus be elevated to a top priority in global health.

Borderline personality disorder (BPD) is a severe mental disorder that is associated with substantial psychosocial impairment and morbidity, disproportionate use of health resources, a high suicide rate, and a reputation for being “untreatable”. A diagnosis of BPD in young people has similar reliability, validity and prevalence to BPD in adults, and almost certainly has serious and pervasive negative repercussions over subsequent decades. Current data are inadequate to inform specific universal or selective prevention programs for BPD. However, they do support including BPD prevention as an outcome when evaluating universal and/or selective interventions for a variety of mental health problems and adverse psychosocial outcomes. The strongest data support early intervention for the emerging BPD phenotype. Early intervention programs will need to be realistic in their aims, require change in clinician attitudes and service systems, and must be mindful of the risk of iatrogenic harm.

IMPORTANCE Clinical trials have neither focused on early intervention for psychosocial impairment nor on the contribution of components of borderline personality disorder (BPD) treatment beyond individual psychotherapy. OBJECTIVE To evaluate the effectiveness of 3 early interventions for BPD of differing complexity. DESIGN, SETTINGS, AND PARTICIPANTS This single-blinded randomized clinical trial recruited young people between March 17, 2011, and September 30, 2015, into parallel groups. The study took place at 2 government-funded mental health services for young people in Melbourne, Australia. Inclusion criteria were age 15 to 25 years (inclusive), recent DSM-IV-TR BPD diagnosis, and never receiving evidence-based BPD treatment. A total of 139 participants were randomized (pool of 876; 70 declined, 667 excluded), balanced for sex, age, and depressive symptomatology. Data analysis completed May 2020. INTERVENTIONS (1)The Helping Young People Early (HYPE) dedicated BPD service model for young people, combined with weekly cognitive analytic therapy (CAT); (2) HYPE combined with a weekly befriending psychotherapy control condition; and (3) a general youth mental health service (YMHS) model, combined with befriending. Therefore, the 3 treatment arms were HYPE + CAT, HYPE + befriending, and YMHS + befriending. Participants were randomly assigned both to 1 treatment arm (in a 1:1:1 ratio) and to a clinician. MAIN OUTCOMES AND MEASURESPsychosocial functioning, measured with the Inventory of Interpersonal Problems Circumplex Version and the Social Adjustment Scale Self-report. RESULTS One hundred twenty-eight participants (104 [81.3%] were female; mean [SD] age, 19.1 [2.8] years; HYPE + CAT: 40 [31.3%]; HYPE + befriending: 45 [35.2%]; YMHS + befriending: 43 [33.6%]) who provided postbaseline data were included in the intent-to-treat analysis. Regardless of group, from baseline to 12 months, there was a mean of 19.3% to 23.8% improvement in the primary outcomes and 40.7% to 52.7% for all secondary outcomes, except severity of substance use and client satisfaction. The latter remained high across all time points. Planned comparisons (YMHS + befriending vs HYPE; HYPE + CAT vs befriending) showed that neither the service model nor the psychotherapy intervention was associated with a superior rate of change in psychosocial functioning by the 12-month primary end point. The HYPE service model was superior to YMHS + befriending for treatment attendance (median [IQR], 22 [19] vs 3 [16] contacts; median duration, 200 [139.5] vs 94 [125] days) and treatment completion (44 of 92 [47.8%] vs 9 of 47 [19.2%]). HYPE + CAT was superior to befriending for treatment attendance (median [IQR], 12 [16.5] vs 3 [9.8] sessions) and treatment completion (24 of 46 [52.2%] vs 29 of 93 [31.2%]). CONCLUSIONS AND RELEVANCEIn this randomized clinical trial of 3 interventions for young people with BPD, effective early intervention was not reliant on availability of specialist psychotherapy but did require youth-oriented clinical case management and psyc...