Table 4.

Other studies

Study design and number of studies (N) with references	Sample size, date, and country of publication	Cohort diagnoses and demographics	Main findings
Mixed therapeutic modalities vs inactive/non-specialist comparators
RCT (n = 3) [220–222]	Sample size: 20–100 (n = 2); > 100 (n = 1) Date: 2010–2019 (n = 3) Country: Europe (n = 3)	Diagnoses: “BPD” diagnosis (n = 3). Demographics: 100% female (n = 1)	RCTs with primary outcomes: On the primary outcomes of RCTs, compared to controls, fewer participants in the intervention group dropped out (1/1) and attempted suicide (1/1), but there was no between-group difference in “BPD” symptoms (0/1). Compared to controls, participants in the intervention group showed greater improvement in most non-primary outcomes
Non-randomised experiments, observational studies, quasi experiment, and natural experiment with pre-post comparison (n = 6) [223–228]	Sample size: 20–100 (n = 3); > 100 (n = 3) Date: 1990–1999 (n = 1); 2000–2009 (n = 3); 2010–2019 (n = 2) Country: Europe (n = 5); North America (n = 1)	Diagnoses: “BPD” (n = 1) or other “personality disorder” diagnosis (n = 4); “personality disorder” diagnosis with self-harm, suicidal, or impulsive behaviour (n = 1). Demographics: not reported	In studies with comparisons over time only, participants improved on following primary outcomes: “BPD” symptoms (1/1), symptom distress, interpersonal relations and social functioning (1/1), and service use (1/1), as well as non-primary outcomes
Mixed therapeutic modalities vs specialist comparators
RCT (n = 1) [229]	Sample size: > 100 (n = 1) Date: 2010–2019 (n = 1) Country: Europe (n = 1)	Diagnoses: “Personality disorder” diagnosis (n = 1). Demographics: not reported	RCTs with primary outcomes: In the 1 RCT, cost-effectiveness did not differ between the step-down treatment and outpatient control group (0/1)
Other individual therapy vs inactive/non-specialist comparators
RCT (n = 5 including 1 pilot. 1 also reported in specialist comparators) [175, 230–233]	Sample size: 20–100 (n = 4); > 100 (n = 1) Date: 1990–1999 (n = 1); 2000–2009 (n = 1); 2010–2019 (n = 3) Country: Europe (n = 3); North America (n = 2)	Diagnoses: “BPD” (n = 1) or other “personality disorder” diagnosis (n = 3); “BPD” diagnosis and major depressive disorder (n = 1) Demographics: 100% female (n = 2); 50–79% White (n = 1)	RCTs with primary outcomes: In 1 RCT, compared to TAU, participants with “BPD” and major depressive disorder receiving Abandonment psychotherapy improved on the primary outcomes (suicidal relapse: 1/1; hospitalisation: 1/1) and non-primary outcomes. In 1 RCT, there was no difference between the immediate and delayed psychoeducation group on the primary outcome (“BPD” severity: 0/1). In 1 RCT, compared to Group Psychotherapy, participants receiving Body-Awareness Group Therapy showed improvement in all non-primary outcomes. In 1 RCT, compared to waitlist controls, participants receiving Brief Adaptive Psychotherapy and Psychodynamic Psychotherapy showed improvement in all non-primary outcomes
Non-randomised experiments, observational studies, quasi experiment, and natural experiment with pre-post comparison (n = 1) [234]	Sample size: 20–100 (n = 1). Date: 2010–2019 (n = 1) Country: North America (n = 1)	Diagnoses: Adverse childhood experiences (n = 1) Demographics: 50–79% White (n = 1)	In 1 study with comparisons over time only, participants with adverse childhood experiences improved on all outcomes
Other individual therapy vs specialist comparators
RCT (n = 2 including 1 also reported in non-specialist) [67, 231]	Sample size: 20–100 (n = 1); > 100 (n = 1) Date: 2000–2009 (n = 1); 2010–2019 (n = 1) Country: Europe (n = 1); North America (n = 1)	Diagnoses: “BPD” diagnosis (n = 1); “BPD” diagnosis and major depressive disorder (n = 1). Demographics: 50–79% White (n = 1)	RCTs with primary outcomes: In 1 RCT focusing on patients with major depressive disorder and “BPD”, there was no difference between Abandonment psychotherapy and TAU on the primary outcome (suicidal relapse: 0/1) and non-primary outcomes. Though no direct contrasts were made, in one RCT of DBT, supportive treatment, and psychodynamic therapy, participants receiving supportive treatment improved on some non-primary outcomes
Social-interpersonal and functional therapies vs non-specialist/inactive comparators
RCT (n = 3) [235–237]	Sample size: 20–100 (n = 1); > 100 (n = 2) Date: 1990–1999 (n = 1); 2000–2009 (n = 1); 2010–2019 (n = 1) Country: Europe (n = 1); North America (n = 1); UK (n = 1)	Diagnoses: “Personality disorder” (n = 1) or “BPD” diagnosis (n = 2) Demographics: not reported	RCTs with primary outcomes: On the primary outcomes of RCTs, compared to controls, participants in the intervention group showed improvement in social functioning (1/1) and social problem-solving skills (1/1), but not general functioning (0/1). Compared to controls, participants in the intervention group showed greater improvement on half of the non-primary outcomes
Social-interpersonal and functional therapies vs specialist comparators
RCT (n = 2 including 1 pilot) [238, 239]	Sample size: 20–100 (n = 2) Date: 1990–1999 (n = 1); 2020- (n = 1) Country: North America (n = 1); UK (n = 1)	Diagnoses: Avoidant “personality disorder” diagnosis (n = 1); at least 3 episodes of self-harm in the past 3 months (n = 1) Demographics: not reported	RCTs with primary outcomes: On the primary and secondary outcomes of RCTs, there were no significant differences between skills training in vivo and skills training in the clinic as well as between Functional Imagery Training (FIT) and delayed FIT across outcomes (0/2)
Self-management and care planning vs self-management
RCT (n = 2) [240, 241]	Sample size: 20–100 (n = 2) Date: 2010–2019 (n = 2) Country: Europe (n = 1); UK (n = 1)	Diagnoses: “BPD” diagnosis and past self-harm (n = 1); “personality disorder” diagnosis (n = 1). Demographics: 50–79% White (n = 1); 100% White (n = 1)	RCTs with primary outcomes: On the primary outcomes of 1 RCT, the Joint Crisis Plan and TAU group did not differ in the frequency or proportion of participants who self-harm (0/1). In non-primary outcomes, compared to TAU, participants receiving Joint Crisis planning did not differ in outcomes. Compared to Structured Goal-Focused Pre-Treatment Intervention (GFPTI), participants receiving therapeutic assessment showed improvements in more than half of non-primary outcomes
Self-management and care planning vs established generic or specialist mental health services
RCT (n = 1) [242]	Sample size: 20–100 (n = 1) Date: 2000–2010 (n = 1) Country: UK (n = 1)	Diagnoses: Severe mental illness and comorbid personality disorder or difficulty (n = 1)	In 1 RCT with primary outcomes, there were no differences between Nidotherapy enhanced assertive outreach and standard assertive outreach in primary outcomes (number of admissions: 0/1; duration of bed use: 0/1) or non-primary outcomes
Non-randomised experiments, observational studies, quasi experiment, and natural experiment with pre-post comparison (n = 3) [243–245]	Sample size: 20–100 (n = 2); > 100 (n = 1) Date: 2010–2019 (n = 3) Country: Europe (n = 1); North America (n = 1); UK (n = 1)	Diagnoses: “Personality disorder” diagnosis (n = 2); major depressive disorder with or without a “personality disorder” diagnosis (n = 1) Demographics: not reported	Non-randomised experiments: In 1 study, compared to TAU, participants receiving collaborative care management showed improvement on the primary outcome (remission of depression: 1/1). In 1 study, compared to TAU, participants in the Collaborative Care Programme (CCP) improved on one of two non-primary outcomes In 1 study with comparisons over time, participants improved on outcomes
Novel mental health service model vs day hospital
RCT (n = 5) [246–250]	Sample size: 20–100 (n = 1); > 100 (n = 4) Date: 2000–2009 (n = 1); 2010–2019 (n = 4) Country: Europe (n = 5)	Diagnoses: “Personality disorder” (n = 4) or “BPD” diagnosis (n = 1) Demographics: not reported	RCTs with primary outcomes: Four RCTs reported results for the same sample at different time points. Compared to outpatient controls, participants in the step-down day hospital group showed no difference in non-primary outcomes at 18 months. On primary outcomes, compared to outpatient controls, participants in the step-down group showed less improvement in functioning (0/1) at 37 months. There were not between-group differences in social and occupational functioning (0/2), interpersonal problems (0/2), depressive symptoms (0/2), symptom severity (0/2), and quality of life (0/2) at 37 months and 6 years as well as functioning (0/1) at 6 years. There were no between-group differences in non-primary outcomes at 37 months and 6 years. In 1 RCT only including patients with a “BPD” diagnosis, compared to outpatient controls, participants in the step-down intervention group showed greater improvement in half of the non-primary outcomes at 6 years
Novel mental health service model vs established generic or specialist mental health services
RCT (n = 2) [251, 252]	Sample size: > 100 (n = 2) Date: 2010–2019 (n = 2) Country: Oceania (n = 1); UK (n = 1)	Diagnoses: “BPD” (n = 1) or “personality disorder” diagnosis (n = 1) Demographics: not reported	RCTs with primary outcomes: On the primary outcomes of 1 RCT, compared to TAU, participants receiving stepped care psychological therapy showed improvement in bed days (1/1) and A&E attendance (1/1). In 1 RCT, compared TAU, participants in the democratic therapeutic community group did not differ in hospital admission (0/1), but showed greater improvement in some non-primary outcomes
Non-randomised experiments, observational studies, quasi experiment, and natural experiment with pre-post comparison (n = 5) [253–257]	Sample size: 20–100 (n = 2); > 100 (n = 3) Date: 2010–2019 (n = 5) Country: North America (n = 1); Oceania (n = 1); UK (n = 3)	Diagnoses: “Personality disorder” (n = 4) or “BPD” diagnosis (n = 1). Demographics: 50–79% White (n = 1)	In studies with comparisons over time only, participants improved on most outcomes
Uncontrolled intervention development studies and single case study with (n = 1) [258]	Sample size: < 20 (n = 1) Date: 2010–2019 (n = 1) Country: UK (n = 1)	Diagnoses: “Personality disorder” diagnosis (n = 1). Demographics: older adults, + 65 (n = 1)	In 1 intervention study with comparisons over time only, there was some evidence for improvement on outcomes, but no statistical analysis was conducted (1/1)