Harmonizing early intervention strategies: scoping review of clinical high risk for psychosis and borderline personality disorder

Aims To map studies assessing both clinical high risk for psychosis (CHR-P) and borderline personality disorder (BPD) in clinical samples, focusing on clinical/research/preventive paradigms and proposing informed research recommendations. Methods We conducted a PRISMA-ScR/JBI-compliant scoping review (protocol: https://osf.io/8mz7a) of primary research studies (cross-sectional/longitudinal designs) using valid measures/criteria to assess CHR-P and BPD (threshold/subthreshold) in clinical samples, reporting on CHR-P/psychotic symptoms and personality disorder(s) in the title/abstract/keywords, identified in Web of Science/PubMed/(EBSCO)PsycINFO until 23/08/2023. Results 33 studies were included and categorized into four themes reflecting their respective clinical/research/preventive paradigm: (i) BPD as a comorbidity in CHR-P youth (k = 20), emphasizing early detection and intervention in psychosis; (ii) attenuated psychosis syndrome (APS) as a comorbidity among BPD inpatients (k = 2), with a focus on hospitalized adolescents/young adults admitted for non-psychotic mental disorders; (iii) mixed samples (k = 7), including descriptions of early intervention services and referral pathways; (iv) transdiagnostic approaches (k = 4) highlighting “clinical high at risk mental state” (CHARMS) criteria to identify a pluripotent risk state for severe mental disorders. Conclusion The scoping review reveals diverse approaches to clinical care for CHR-P and BPD, with no unified treatment strategies. Recommendations for future research should focus on: (i) exploring referral pathways across early intervention clinics to promote timely intervention; (ii) enhancing early detection strategies in innovative settings such as emergency departments; (iii) improving mental health literacy to facilitate help-seeking behaviors; (iv) analysing comorbid disorders as complex systems to better understand and target early psychopathology; (v) investigating prospective risk for BPD; (vi) developing transdiagnostic interventions; (vii) engaging youth with lived experience of comorbidity to gain insight on their subjective experience; (viii) understanding caregiver burden to craft family-focused interventions; (ix) expanding research in underrepresented regions such as Africa and Asia, and; (x) evaluating the cost-effectiveness of early interventions to determine scalability across different countries. Systematic Review Registration https://osf.io/8mz7a.


Introduction
Adolescence and young adulthood are crucial developmental periods and, given 62.5% of mental disorders have an onset before age 25 (Solmi et al., 2022), are an important setting for the provision of early intervention strategies.These are aimed at preventing the onset of severe mental health conditions and their most adverse outcomes, including reduced life expectancy, disability, and limited academic and work attainments (Fusar-Poli et al., 2021;World Health Organization, 2022).Consistently, within the context of primary indicated prevention, early detection and intervention services have been implemented worldwide for youth manifesting the first signs and symptoms of emerging mental disorders (Shah et al., 2020).
One of the most consolidated preventive paradigms is the "clinical high-risk for psychosis" (CHR-P) paradigm, which focuses on helpseeking youth with sub-threshold psychotic symptoms, functional impairments, and presenting with up to 25% likelihood of developing a first-episode psychosis (FEP) over 3 years (Fusar-Poli et al., 2020a;Salazar de Pablo et al., 2021b).Notably, over three-quarters of CHR-P youth present with comorbid (i.e., co-existing) non-psychotic mental disorders that need clinical attention (Solmi et al., 2023).Among these, one of the most severe and potentially disabling is borderline personality disorder (BPD), which has been observed in 10% of CHR-P cases (Solmi et al., 2023) and displays a pervasive pattern of clinical manifestations, including unstable interpersonal relationships, affective instability, and self-mutilating behaviors (Chanen and Thompson, 2018;American Psychiatric Association, 2022).
Notably, BPD is also a "novel public health priority" (Chanen et al., 2017) and has been the subject of growing clinical and research interest, which has led to a specific early intervention paradigm focusing on young people with BPD and sub-syndromal borderline personality pathology (Chanen and Thompson, 2018).Clinical presentations of BPD patients are complex, and comorbid psychotic symptoms are frequently reported, with 29-50% of BPD cases experiencing auditory hallucinations (Fagioli et al., 2015;Cavelti et al., 2021).
Overall, early intervention paradigms focusing on either CHR-P or BPD show critical differences.For example, early services focusing on CHR-P (e.g., Personal Assessment and Crisis Evaluation; PACE) (Yung et al., 2007) strive to prevent the onset of full-blown psychotic disorders, whereas clinical centers focusing on BPD (e.g., Helping Young People Early; HYPE) (Chanen et al., 2009) seek to assess and address emerging severe personality disorders (PDs).
Although such services have been implemented to meet the clinical needs of different populations, CHR-P and BPD can co-exist.Moreover, they also share crucial outcomes, including high societal costs and long-term risks for self-harm, unemployment, and disability (The Public Health Group, 2005;Chanen, 2017;Fusar-Poli et al., 2020a, 2021).
However, although their co-occurrence is well-established, the consensus on the best clinical pathways for youth with both CHR-P state and BPD-even in attenuated forms-is limited, highlighting crucial shortcomings of current early paradigms.First, international clinical guidelines are specific to CHR-P (NICE, 2014;Schmidt et al., 2015) or BPD (NICE, 2009;Simonsen et al., 2019), with non-exhaustive information on the clinical management of youth with both clinical conditions.Second, treatment clinics for CHR-P and BPD may be separated and disconnected-even geographicallyhindering fundamental collaborations among mental health systems and timely intervention.Third, although recent transdiagnostic approaches are promising since they "cut across, " single diagnostic entities, such models still need to be implemented at scale (Shah et al., 2020).Ironically, even though the comorbidity concept can be considered partially artifactual (Nordgaard et al., 2023), the co-existence of CHR-P and borderline personality pathology impacts "tangibly" both referral pathways of young people and decision aids of clinicians operating in mental health services.It is essential to produce research recommendations for future studies that may advance clinical care, also considering the urgent transformation for mental health argued in the recent World Health Organization (WHO) mental health report (World Health Organization, 2022).
Given this background, the current scoping review aims to explore original research on CHR-P state and BPD.This is essential to propose informed research recommendations.A scoping review design was selected (Tricco et al., 2018).In contrast with previous reviews, we do not seek to establish the meta-analytic prevalence of BPD in CHR-P samples (Boldrini et al., 2019;Solmi et al., 2023) nor explore the clinical overlap/relationship between early psychosis and BPD (West et al., 2021;Biancalani et al., 2023); instead, we aim to systematically screen and explore the body of studies including CHR-P and BPD, map clinical/research/preventive paradigms and generate informed research recommendations across preventive paradigms.2 Materials and methods

Review questions
The proposed scoping review was performed in line with the PRISMA-ScR and JBI methodology for scoping reviews (Peters et al., 2015;Tricco et al., 2018;Peters et al., 2020;Khalil et al., 2021) and previous scoping reviews (Fornaro et al., 2021).See Supplementary material S1.The a-priori protocol was pre-registered in Open Science Framework (OSF: https://osf.io/8mz7a).Deviations from the original protocol are reported in the Supplementary material S2.

Inclusion/exclusion criteria
Included were: (a) primary research studies (i.e., "standard" research articles, letters to the Editor, brief reports, single cases, conference abstracts and, in general, "grey literature") with any study design (e.g., randomized controlled trials, observational studies, crosssectional and longitudinal studies), (b) focusing on clinical samples ("Population"), (c) using valid and reliable measures or diagnostic criteria to assess both BPD/BPD symptoms and CHR-P state/ attenuated psychosis syndrome (APS) ("Concept"), (d) reporting information on at-risk state (or psychotic symptoms) and PDs or personality pathology (schizotypal personality disorder excluded since it is part of CHR-P inclusion criteria) in the title and/or abstract and/or keywords, and (e) written in English.
Excluded were: (a) reviews, (b) studies not focusing on clinical samples (e.g., general population), (c) not written in English.No restrictions were applied on context or geographical location ("Context").Potential overlap among samples was not an exclusion criterion since this scoping review aimed to gather any relevant primary research study to map conceptualizations of clinical care/ services, emphasizing the clinical/research "lens" adopted by the authors of each relevant study.

Search strategy
The search strategy aimed to identify both published and unpublished studies.A first limited search of PubMed, EBSCO/ PsycINFO, and Web of Science was conducted by GLB.The initial search results were shared and discussed with the other authors of the current study.The text words contained in the titles and abstracts of relevant studies and the index terms (plus other words related to the topic of the current scoping review) were employed to develop a full search strategy for PubMed, Web of Science, and EBSCO/PsycINFO (see Supplementary material S3).The reference list of the included studies was screened for additional studies.Finally, further studies were searched on ResearchGate.A multi-step literature search was performed on Pubmed, Web of Science, and EBSCO/PsycINFO for studies published from inception to the 23rd August 2023.Citations were uploaded into Mendeley Manager/Mendeley Desktop, and duplicates were automatically excluded.GLB and a supervised student (see "Acknowledgments") independently conducted the screening.
First, titles and abstracts were checked, and then the full texts were examined.Reasons for exclusion at the full-text level were recorded.Disagreements were solved by contacting a third judge (AT).

Data extraction
Data were extracted by GLB.The data extracted on the characteristics of the studies was checked by FF.The following were extracted: (a) Country, sample (N, mean age, sex), type of publication (i.e., peer-review journal, grey literature, book), year, study design, and study goals; The .xls data charting file was updated while extracting the data.Potential disagreements among the authors were solved via discussion.Authors of included articles were contacted for missing or additional information.

Data analysis and presentation
We presented the findings in a narrative synthesis and one table and organized them into major concepts identified across the included studies.To answer the review questions (a) and (b), we organized the included studies and their data into four major concepts reflecting different clinical or research paradigms: BPD as a comorbidity among CHR-P youth (k = 20); attenuated psychosis syndrome (APS) as a comorbidity among BPD inpatients (k = 2); mixed samples (k = 7); transdiagnostic approaches (k = 4).Ten research recommendations beyond diagnostic silos were finally proposed.The results were discussed in the context of international guidelines (NICE, 2009(NICE, , 2014;;Schmidt et al., 2015;Simonsen et al., 2019) and the recent WHO mental health report (World Health Organization, 2022).

Study selection
972 studies were detected across registries and databases, 322 of which were duplicates, and 9 records were identified via other methods (Figure 1).585 studies were excluded at the title-abstract level, and 41 were excluded after examining the full-texts.Reasons for exclusion at the full-text level are reported in the Supplementary material S4.We ultimately included 33 studies, and their main characteristics are displayed in Table 1.A total of 14 studies were conducted in clinical centers located in Europe, 10 in Australia, 7 in the US, and 2 studies in multiple countries.Included studies were published between 2012 and 2023, with the latter being the year with the most studies (k = 5).Overall, 25 publications were standard research articles, 2 were conference abstracts/conference papers, 2 were dissertations, 2 were brief reports, and 2 were Letters to the Editor.15 studies were cross-sectional, 13 were cohort studies, and 5 were case-control studies.-Lutter et al., 2012;Thompson et al., 2012;Byars, 2013;Nelson et al., 2013;Barrantes-Vidal et al., 2014;Rutigliano et al., 2016;Fusar-Poli et al., 2017;Ryan et al., 2017;Kotlicka-Antczak et al., 2018;Madsen et al., 2018;Sevilla-Llewellyn-Jones et al., 2018;O'Connor et al., 2019;Paust et al., 2019;Hadar et al., 2020;Boldrini et al., 2020b;DaBreo-Otero, 2021;West et al., 2022;Ceccolini et al., 2023;Pelizza et al., 2023;Tronick et al., 2023) focused on early detection and intervention within the framework of the CHR-P paradigm.Overall, the clinical population comprised CHR-P patients and, in some studies, control patients, accessing CHR-P clinics or mental health services.CHR-P patients reported a range of comorbid mental disorders, including BPD.The studies' goals and the clinical and research recommendations of the study authors did not focus solely on BPD, encompassing a range of clinical and research issues in the clinical management of CHR-P patients.
Research recommendations within the CHR-P framework included developing and test new early intervention strategies for comorbid PDs, including BPD (Schultze-Lutter et al., 2012), assessing personality and/or trauma in intervention studies (Thompson et al., 2012;Hadar et al., 2020;Boldrini et al., 2020b), and investigating outcomes other than conversion to psychosis (e.g., development of non-psychotic mental disorders) (Rutigliano et al., 2016) in comparison with healthy controls (Fusar-Poli et al., 2017).West et al. (2022) emphasized research into the antecedents of symptoms.One study suggested investigating self-disturbances-for details, see (Henriksen et al., 2021)-to improve the (challenging) differential diagnosis between borderline personality pathology and schizophrenia spectrum disorders (Nelson et al., 2013;Ryan et al., 2017).Research efforts with larger samples (Sevilla-Llewellyn-Jones et al., 2018;Paust et al., 2019) and longitudinal study designs (Thompson et al., 2012;Rutigliano et al., 2016;O'Connor et al., 2019) were recommended, and the need to provide more understanding and further treatment options was emphasized (Madsen et al., 2018).

APS as a comorbidity among BPD inpatients
2 studies (Gerstenberg et al., 2015;Salazar de Pablo et al., 2020b) focused on patients with a wide range of mental health conditions, including BPD, with or without APS.Specifically, samples from both studies were composed of inpatient (hospitalized) adolescents or young adults admitted for non-psychotic mental disorders at the Child and Adolescent Inpatient Unit of the Zucker Hillside Hospital, New York.
Clinical recommendations in APS adolescents included age-sensitive "staged" intervention models (Gerstenberg et al., 2015).Moreover, targeting poor stress tolerance and perceptual abnormalities in need-based interventions was suggested to foster quality of life and reduce the burden experienced by both patients and their families (Salazar de Pablo et al., 2020b).
Research recommendations of Salazar De Pablo et al. (2020b) included investigating comorbid mental health conditions in APS and their relevance for the risk of developing psychosis-especially in adolescents-while Gerstenberg et al. (2015) emphasized the need for long-term prospective studies with large samples to illuminate APS and its frequency, associated characteristics, evolution from childhood to adulthood, and long-term outcomes.

Mixed samples
7 studies (Koutsouleris et al., 2014;McMillan et al., 2017;Sanchez et al., 2019;Seiler et al., 2020;Burke et al., 2022;Gajwani et al., 2022;Gruber et al., 2023) included patients at CHR-P and patients with BPD, with or without additional samples of patients with FEP or major depressive disorder/mood disorders and healthy controls.In this theme, CHR-P and BPD represented different clinical populations (even though some CHR-P youth also displayed a comorbid BPD).Four studies focused on Youth Mental Health Services in Melbourne, which provided descriptions of preventive services for adolescents and young adults, including HYPE (for BPD), PACE (for CHR-P), and additional early clinics for mood disorders and FEP.These studies also delivered information about referral pathways (McMillan et al., 2017;Sanchez et al., 2019;Seiler et al., 2020;Burke et al., 2022).
Clinical recommendations included assessing sub-threshold positive symptoms in help-seeking youth even though their major complaint is non-psychotic (Seiler et al., 2020), screening for neurodevelopmental disorders and adverse childhood experiences (Gajwani et al., 2022), integrating sexual health screening into initial assessment (Sanchez et al., 2019), and implementing a range of strategies to address sexual health and sexual dysfunction (McMillan et al., 2017).Gruber et al. emphasized the clinical implications of comprehensive assessment measures to evaluate identity-and selfdisturbances (Gruber et al., 2023).Burke et al. (2022) argued that early intervention clinics may work alongside so-called "public health approaches"-for details, see (Ajnakina et al., 2019)-to lower the exposure to environmental factors (e.g., cannabis) associated with an increased risk for psychosis.However, other methods are needed to detect more cases at risk for psychosis.For example, youth reaching emergency departments with self-harm may be targeted by early clinics since they appear to be at increased risk for psychosis-for details, see Bolhuis (2021).
Research recommendations included employing longitudinal study designs (Gajwani et al., 2022;Gruber et al., 2023), investigating more specific neuroanatomical biomarkers (Koutsouleris et al., 2014), and replicating relevant study findings.For example, Burke et al. (2022) showed fewer voluntary and involuntary hospital admissions in youth who had transitioned to psychosis from PACE, HYPE, or primary care compared to cases presenting directly with FEP.Other authors highlighted the need for clinical pathways to address sexual health and sexual dysfunction in youth with mental health conditions (McMillan et al., 2017;Sanchez et al., 2019).

Transdiagnostic approaches
4 studies (Agius et al., 2013;Hartmann et al., 2021;Monego et al., 2022;Destrée et al., 2023) adopted a transdiagnostic approach, 3 of which (Hartmann et al., 2021;Monego et al., 2022;Destrée et al., 2023) applied the recent "clinical high at risk mental state" (CHARMS) criteria, which identify potentially (partially) overlapping at-risk states for psychosis, BPD, mania/bipolar disorder, and severe depressive disorder.Essential concepts are the "clinical staging" model and "pluripotency." While the former refers to a dimensional approach that collocates the person in a continuum from an asymptomatic state to chronic and disabling conditions, the latter refers to an agnostic stance about the trajectory of mental disorders (i.e., multiple outcomes are possible) (Hartmann et al., 2021).CHARMS approach aims to capture both "homotypic progression" (e.g., an individual at CHR-P goes on to develop FEP) and "heterotypic progression" (e.g., an individual with sub-syndromal borderline personality pathology goes on to develop a major depressive disorder) (Hartmann et al., 2021).
Before developing CHARMS criteria, Agius et al. ( 2013) recommended using the CAARMS to assess difficult patients.Overall, an overarching goal of transdiagnostic approaches is to "maximize clinical utility" (Hartmann et al., 2021).Accordingly, research recommendations included broadening CHARMS criteria (e.g., by including also eating disorders and obsessive-compulsive disorder) (Hartmann et al., 2021), exploring conversion to different mental health conditions of each CHARMS group and their overlaps, investigating the role of transdiagnostic or specific symptoms at intake and functioning in predicting CHARMS exit mental health conditions (Monego et al., 2022), and adopting more dynamic research approaches (Hartmann et al., 2021).Finally, Destrée et al. suggested exploring the relationship between specific stressful experiences and obsessive-compulsive dimensions (Destrée et al., 2023).

Discussion
The current scoping review revealed heterogeneous clinical paradigms.Specifically, the included studies were organized into four major themes: BPD as a comorbidity among CHR-P youth, APS as a comorbidity among BPD inpatients, mixed samples, and transdiagnostic approaches.Notably, high heterogeneity was observed both across themes and within each theme.Finally, research recommendations beyond diagnostic silos were proposed.
The core finding of this scoping review is that young people with CHR-P/APS and/or BPD may be subject to a range of clinical and Overall, no clear therapeutic approaches have been developed for people presenting with both conditions.There is some evidence of therapeutic modalities either for BPD or CHR-P but not for both.Also, the targets of the intervention are different, with mainly transition to psychosis in CHR-P population and social and vocational functioning in BPD clinics.
Notably, the differential diagnosis is challenging since key features of a BPD diagnosis (e.g., "unstable self-image or sense of self " and experiencing "chronic feelings of emptiness") have been consistently reported in literature focusing on schizophrenia spectrum disorders (Lingiardi, 2019;Zandersen and Parnas, 2019).This has crucial implications since patients may receive diverse treatments in highly specialized services based on diagnosis (Zandersen et al., 2019;Zandersen and Parnas, 2020).
This large body of topics and clinical and research recommendations identified in the first theme (BPD as a comorbidity among CHR-P youth) indirectly corroborates the heterogeneity of the CHR-P population observed in previous meta-research in terms of clinical presentation, clinical correlates, clinical services, and long-term outcomes (Beck et al., 2019;Fusar-Poli et al., 2020a;Catalan et al., 2021;Salazar de Pablo et al., 2021b, 2021a;Bargiota et al., 2023;Solmi et al., 2023).The second theme (APS as a comorbidity among BPD inpatients) and the fourth theme (transdiagnostic approaches) reflect a growing clinical and research interest in APS (Salazar de Pablo et al., 2020a) and transdiagnostic frameworks (Shah et al., 2020;Uhlhaas et al., 2023), respectively.Finally, some studies in the third theme (mixed samples) suggested the benefits of accessing early services before developing psychosis (e.g., reduced hospitalizations) (Burke et al., 2022), providing details into youth mental health services, entry points for potential clients, and pathways of referral to specialist clinics.

Research recommendations
Despite the growing body of research, early approaches are hindered by shortcomings that need to be addressed by future empirical investigations.Accordingly, we proposed 10 research recommendations (Table 2) generated by harmonizing our scoping review results with current research gaps, clinical guidelines (NICE, 2009(NICE, , 2014;;Schmidt et al., 2015;Simonsen et al., 2019), and the recent WHO mental health report (World Health Organization, 2022).
First, little research has focused on referral pathways of young people at risk of developing severe mental disorders.Research efforts in this field may advance coordination among different clinical services and different clinical paradigms, promoting timely intervention and appropriate referrals for each patient profile.
Second, international recommendations aim to keep the duration of untreated psychosis (i.e., the timing between the first symptom and initiation of adequate intervention) (Marshall et al., 2005) below 3 months (Bertolote and McGorry, 2005), given its prognostic significance (Howes et al., 2021).Developing early detection strategies in innovative clinical settings-e.g., emergency departments (Solmi et al., 2020)-might improve timely referral to appropriate care, reducing the duration of untreated symptoms.
Third, early clinics may be actively involved in developing programs to improve the so-called "mental health literacy" (i.e., "the ability to recognize and possess knowledge of a variety of different profiles of emerging and established mental disorders […]") (Fusar-Poli et al., 2020b) in the general population, thus promoting help-seeking behaviors (Jorm, 2000;Jorm et al., 2006;Altuncu et al., 2023).
Fourth, there is little consensus on the best intervention for CHR-P youth with BPD (or vice-versa).Research efforts conceptualizing comorbid conditions as a complex system (e.g., network analysis) may improve understanding of early psychopathology manifestations and potentially suggest relevant intervention targets (Nelson et al., 2017;Borsboom et al., 2021;Ong et al., 2021;Lo Buglio et al., 2022).
Fifth, further research on the risk of developing psychosis in BPD patients may be crucial to monitor and, ideally, prevent the onset of full-blown psychotic symptoms.Moreover, further research is needed on the onset of diagnosable BPD from sub-syndromal borderline personality pathology.
Sixth, developing transdiagnostic interventions is a growing clinical and research need (Reininghaus et al., 2023).
Eight, caregivers may often need to demonstrate disabling mental health conditions in young people for whom they care to gain the attention of psychiatric services (McGorry et al., 2022).Investigating the burden experienced by caregivers may help develop comprehensive interventions considering the whole family system, further supporting the recovery process in the young person.
Ninth, none of the included studies originated from Asia and Africa, suggesting a need for research in this field across wider geographical regions.

Transdiagnostic research recommendations
(1) Improve research on referral pathways across early intervention services (2) Expand early detection strategies in innovative settings (e.g., emergency departments) to reduce the duration of untreated symptoms.
(3) Develop programs to improve mental health literacy in the general population, improving help-seeking behaviors (4) Improve research that views BPD and CHR-P comorbidity as a complex system, adopting methods like network analysis to better understand and target early psychopathology.
(5) Track BPD patients who go on to develop psychotic symptoms/track patients with sub-threshold BPD who go on to develop full-blown BPD.Lo Buglio et al. 10.3389/fpsyg.2024.1381864Frontiers in Psychology 13 frontiersin.org Tenth, further cost-effectiveness research (Aceituno et al., 2019) on early intervention services in multiple countries is crucial to provide robust indications about their feasibility at scale.

Strengths and limitations
The main strengths of this scoping review include broad inclusion criteria, a systematic study selection process, results focusing on a range of clinical/preventive paradigms, and informed research recommendations toward paradigm integration.This study has several limitations.First, our study design did not allow for the development of clinical guidelines.Nevertheless, our study allowed for generating informed research recommendations since we harmonized findings of this scoping review with research gaps and clinical guidelines.Second, due to multiple clinical and research recommendations in the included studies, we selected and emphasized the most consistent with the aims of this current scoping review.Third, most studies were conducted in Western countries, limiting the generalizability of the findings.

Conclusion
In summary, this scoping review mapped clinical paradigms in studies on CHR-P and BPD, revealing heterogeneous conceptualizations of clinical care, preventive and research paradigms.No clear therapeutic modalities are available for people presenting with both CHR-P and BPD.Our research recommendations can be helpful to improve cooperation and knowledge integration among preventive approaches and generate evidence with real-world clinical implications.
(b) Measures employed to assess BPD and CHR-P; (c) Information on other (non-borderline) PDs; (d) Research recommendations of authors of included studies; (e) Clinical recommendations of authors of included studies; (f) Concepts regarding early intervention services and early intervention strategies; (g) Potential other relevant concepts were detected, and research gaps were highlighted.
in CHR-P samples.Pelizza et al. (2023) highlighted the need to overcome the barriers between adult and child/adolescent mental health services, reduce antipsychotic dosage and delivering psychosocial interventions, and establish cultural mediation services within early intervention clinics.Other clinical recommendations included providing non-stigmatizing settings (Kotlicka-Antczak et al., 2018), fostering protective factors [e.g., social support Tronick

FIGURE 1
FIGURE 1The PRISMA-ScR flow diagram of the literature search and the selection process.
gender patients, mean age = 17.37 (SD = 3.4) and 26 gender-expansive patients, mean Age = 18.96 (SD = 4.18) To explore the proportion and clinical characteristics of gender-expansive patients seeking CHRdifferent CHR-P criteria (including established ones), 70.5% males To investigate the progression of Axis I and Axis II mental conditions.Mean follow up = 2411 CHR-P individuals, Mean age = 23.04 (SD = 5.6), 56% males; 299 non-CHR-P individuals, Mean age = 23.21(SD = 5.05), 57% males To examine the long-term validity of CHR-P for predicting non-psychotic mental disorders.Mean follow-up: 1472 days (SD = 1,171 days) Mean age = 18 (SD = 2.9), 40.7% males To examine whether, at baseline entry in CHR-P clinic, perceptual abnormalities are (a) more prevalent in cases with comorbid diagnoses, (b) more prevalent in cases with childhood adversities, (c) correlated with comorbid clinical diagnoses or history of childhood adversities.Follow-up ranged from 1.2 to 6.5 years (Median = 4.5 years) Zurich 10 patients not meeting at-risk criteria, 40% of males, Mean age = 22.2 (SD = 4.89); 60 patients meeting different CHR-P criteria, 45% males, Mean age = 21.98 (SD = 5.34).To examine borderline symptoms in patients at CHR-P and their potential impact on conversion to psychosis.Follow-up: 52 CHR-P youth, 61.5% males (Mean age at entry = 23.42;SD = 2.97) To describe the mental health service over the course of its clinical activity.

( 6 )
Develop transdiagnostic interventions.(7) Engage youth with lived experience of BPD and CHR-P to gain insight into their subjective experiences for better clinical management.(8) Investigate the burden on caregivers to aid in developing interventions that support both the patient and the family system.

( 9 )
Expand research to include studies from underrepresented regions such as Asia and Africa.(10)Conduct research on the cost-effectiveness of early intervention services in various countries to assess scalability.

TABLE 1
Characteristics of the included studies.

TABLE 1 (
Continued) ). Clinics/Services: ASPA: Assessment and Single point of Access team; CAMEO: Cambridgeshire and Peterborough Assessing, Managing and Enhancing Outcomes; CEDAR: Center for Early Detection, Assessment, and Response to Risk; EPPIC: Early Psychosis Prevention and Intervention Centre; FETZ: Cologne Early Recognition and Intervention Centre for mental crises; HYPE: Helping Young People Early; NAPLS: North American Prodrome Longitudinal Study; NHS: National Health Service; OASIS: Outreach and Support in South London; PORT: Programme of Recognition and Therapy; PACE: Personal Assessment and Crisis Evaluation; RAP: Recognition and Prevention Program; PARMS: Parma At-Risk Mental States; SLaM: South London and the Maudsley; NHS Foundation Trust; YMC: Youth Mood Clinic; ZInEP: Zürcher Impulsprogramm zur nachhaltigen Entwicklung in der Psychiatrie.
For example, BPD can be considered a comorbid mental disorder in CHR-P/APS patients that needs to be assessed and treated.Moreover, CHR-P and BPD can also represent admission diagnoses to diverse early clinics.Finally, sub-threshold psychotic symptoms and sub-threshold BPD can both be part of broader transdiagnostic approaches.

TABLE 2
Research recommendations.