The Norwegian network for personality disorders - development, contributions and challenges through 30 years.

BACKGROUND: Established in 1992, the Norwegian Network for Personality Disorders (The Network) is a clinical research collaboration of specialist mental health and addiction services in Norway. Its primary focus is to facilitate systematic and relevant clinical assessment for patients with personality disorder and evaluate progress in psychotherapeutic treatment. However, large-scale data registers for personality disorder are still unique. This article presents the circumstances that led to the establishment of the Network, and its development and challenges in many areas, and through various phases. METHODS: In the following, we will outline how this close interaction between researchers, clinicians, and well-adapted systems has facilitated cooperation and clinical research. We will highlight some key factors that have been decisive during the network's development, and not least for further adaptation and existence. RESULTS: Through 30 years, the Network has succeeded in establishing a large and sustainable clinical research collaboration with a persistent focus on personality disorder and psychotherapeutic treatment. The collaboration has resulted in a broad range of scientific contributions to the understanding of personality disorder, assessment and measurement methods, treatment alliance, clinical outcomes, service utilization, and costs. In addition, The Network has also resulted in a number of synergy effects that have benefited clinicians, patients, and researchers. CONCLUSIONS: The Norwegian Network for Personality Disorders has become an acknowledged institution in the field. Many aspects of its development, organization, maintenance, and solutions to challenges may be relevant to others who plan to establish, maintain, or further develop similar collaborations.

A borderline focused Reflective Functioning measure - Interrater reliability of the Mentalization Breakdown Interview.

OBJECTIVE: Mentalizing difficulties can be considered the core psychopathology of borderline personality disorder (BPD). Typical failures of mentalizing are targets in therapy for BPD. They are related to severe distress, relational problems, self-destructive behaviors, violence, or substance misuse. A major obstacle in BPD treatment research is the lack of suitable and easily administrated methods to assess mentalizing ability during treatment. The Mentalization Breakdown Interview (MBI) is a new method for capturing episodic mentalizing difficulties occurring in close relationships. Interviews are videotaped and scored in accordance with the Reflective Functioning Scale (MBI-RF). In this way the patients' ability to retrospectively reflect over such episodes are evaluated. This study investigates the interrater reliability of MBI-RF. METHODS: The study includes videotapes of MBIs from 32 patients with BPD in an outpatient clinic specialized on mentalization-based treatment (MBT). The MBIs were performed by MBT therapists. Three certified raters scored MBI-RF. RESULTS: The interrater reliability was good for MBI-RF. CONCLUSIONS: The MBI is promising as a BPD-focused method for the assessment of Reflective Functioning.

Avoidant and borderline personality disorder patients during the first Covid-19 wave in Norway - a survey-based comparison of therapy changes and patients' accommodations.

BACKGROUND: Patients with personality disorders (PDs) often have insecure attachment patterns and may be especially vulnerable to abrupt treatment changes. Patients with borderline PD (BPD) are often considered vulnerable to treatment interruption due to chronic fear of abandonment. Nonetheless, other PDs are poorly investigated. In the first Covid-19 wave in Norway, in-person treatment facilities and group treatments were strongly restricted from March 12th until May/June 2020. OBJECTIVES: To examine and compare changes in outpatient treatment for patients with avoidant (AvPD) and BPD during the first Covid-19 wave in Norway, and patients' reactions to these changes. METHODS: The study is based on a cross-sectional survey distributed to 1120 patients referred to 12 different PD treatment units on a specialist mental health service level within the Norwegian Network for Personality Disorders. The survey included questions on treatment situation, immediate reactions, and changes during the crisis. From 133 responders (response rate 12%), 40 patients reported BPD and 30 AvPD as diagnosis. RESULTS: All patients were followed up from their therapist after March 12th. Almost all patients in both groups expressed satisfaction under the new circumstances. Both groups experienced the same regularity as before, but more AvPD patients reported less than weekly consultations. AvPD patients reported more negative feelings about changes in therapy, and missed the therapy and group members more than the BPD group. CONCLUSION: After the lockdown, BPD patients received a closer follow-up than AvPD patients, and the latter reported more negative feelings related to change in their treatment situation.

Vulnerability of personality disorder during the Covid-19 crises - a multicenter survey of treatment experiences among patients referred to treatment.

BACKGROUND: The societal shutdown due to the Covid-19 pandemic involved mental health services for personality disorder (PD) and was introduced from 12 March 2020 in Norway. Rapid implementation of treatment modifications was required for patients typically characterized by insecure attachment and vulnerability to separation. AIM: To investigate immediate reactions to the shutdown of services; alternative treatment received; and differences related to age in a clinical sample of patients with PD. DESIGN: A survey performed from June to October 2020 (after the first Covid-19 wave) among 1120 patients from 12 units offering comprehensive group-based PD programs. RESULTS: The response-rate was 12% (N = 133). Negative feelings of anxiety, sadness, and helplessness were noteworthy immediate reactions, but the dominating attitude was accommodation. Younger patients (<26 years) reported more skepticism and less relief. Modified treatment was mainly telephone therapy. Digital therapy was less available, but was more frequent among younger patients. A minority received digital group therapy. Most patients rated the frequency and quality of modified treatments as satisfactory in the given situation, but also worried about own treatment progress, lack of group therapy, and 47% missed seeing the therapist when having telephone consultations. CONCLUSION: The survey confirms a radical modification from comprehensive group-based PD programs to telephone consultations, low availability of digital consultations and group treatments. Taking a short-term, first wave perspective, the survey indicates a noteworthy capacity among poorly functioning patients for accommodating to a clearly challenging situation, as well as considerable concern about treatment progress.

Psychometric evaluation of the Norwegian Toronto Alexithymia Scale (TAS-20) in a multisite clinical sample of patients with personality disorders and personality problems.

OBJECTIVE: Psychometric properties of 20-item Toronto Alexithymia Scale (TAS-20) have been widely analyzed, but the validity and psychometric qualities of the TAS-20 in populations with personality disorders are still poorly understood. The aim of the current study was to analyze the factor structure and validity of TAS-20. METHOD: Data were extracted from a multisite clinical sample of patients with personality disorders or personality-related problems referred to specialist mental health services in Norway. RESULTS: With one exception, TAS-20 revealed acceptable psychometric properties. Variations of TAS-20 are associated with other clinical measures of distress and severity. Anxiety disorders, borderline, and avoidant personality disorders were all highly related to levels of TAS-20. The TAS-20 also revealed unique variance not accounted for by subjective distress, symptom disorders, or dysfunctional personality traits. CONCLUSION: The TAS-20 is a relevant instrument for use in assessment of personality disorders, but one subscale should be improved.

A multi-center psychometric evaluation of the Severity Indices of Personality Problems 118 (SIPP-118): Do we really need all those facets?

PURPOSE: The Severity Indices of Personality Problems 118 (SIPP-118) is a self-report questionnaire that aims to measure core components of (mal)adaptive personality functioning that can change over time. In this study, we aimed to assess the facet strength of the 16 facets across three large clinical samples. METHODS: Data from Norwegian and Dutch psychiatric patients were analyzed in this international multi-center study (N1 = 2814, N2 = 4751, N3 = 2217). Bi-factor modeling was used to assess to what degree the SIPP items tap into an overall general factor. The incremental value (distinctiveness) of the facets was studied using proportional reduction in mean squared error (PRMSE) based statistics. RESULTS: The estimated model showed adequate fit. The explained common variance (ECV) attributable to the general factor equaled 50% for all three samples. All but two facets (stable self-image and frustration tolerance) showed sufficient levels of distinctiveness. The findings were observed to be comparable across the three samples. CONCLUSION: Our findings showed that the general factor was relatively weak, and the facets had a clear incremental value.

Level of alexithymia as a measure of personality dysfunction in avoidant personality disorder.

BACKGROUND AND OBJECTIVES: Avoidant Personality Disorder (AvPD) is considered a mild to moderate personality disorder. However, few studies have focused on the heterogeneity of AvPD in terms of symptoms and severity. In the current study we set out to replicate and extend earlier findings showing that there is variation among patients with AvPD in terms of alexithymia and, further, that this variation is especially associated with specific facets of personality functioning and is not explained by measures of depression, symptom severity, or co-occurring personality disorder traits. METHOD: We used intake data from a sample of AvPD patients (n = 56) who had been treated in similar outpatient services. Alexithymia was measured using the Toronto Alexithymia Scale (TAS-20). Patients filled out questionnaires that were analysed using linear regression models. RESULTS AND CONCLUSIONS: Using well-established cut-off points for low, intermediate and high levels of alexithymia we found an almost equal distribution of alexithymia groups in our sample. Alexithymia was associated with higher personality dysfunction on twelve out of sixteen facets of personality functioning. For eight of these personality facets the alexithymia total score explained significant variance even after controlling for self-reported depression, symptom severity and clinician ratings of personality disorder. Results suggest that AvPD is heterogeneous and that alexithymia may be important as an indicator of severity of specific personality dysfunction.

Vulnerability of personality disorder during COVID-19 crises: a multicenter survey of mental and social distress among patients referred to treatment.

BACKGROUND: Relational and emotional problems, dysregulation, self-harming or substance abuse often characterize personality disorders (PD). In Norway, COVID-19 restrictions led to an abrupt shutdown of services from 12 March 2020 also including specialized PD treatments. AIMS: The objective of this study was to investigate social and mental distress among patients with PDs during the first COVID-19 wave. DESIGN: A survey was distributed after the first COVID-19 wave (June-October 2020) among 1120 patients from 12 PD treatment units. RESULTS: The response rate was 12% (N = 133). The survey reflected impairment of occupational activity (53% <50% activity last 6 months), life quality (EQ-5D-VAS: 56, SD 19), and personality functioning (LPFS-BF ≥12: 81%, 35% avoidant PD, 44% borderline PD) and high levels of depression and anxiety (PHQ-9 ≥ 10: 84%, GAD-7 ≥ 10: 68%), 49% with health-related anxiety. Problem increase was reported for anxiety (28%), depression (24%), aggression (23%), substance use (14%), and 70% of parents had more child-care difficulties. Self-destructive behaviors (26%) did not increase. The majority (78%) reported increased or unchanged social isolation and loneliness. Occupational activity declined with negative effects on part-time jobs/rehabilitation. Therapist contact was mainly telephone-based (63% ≥ weekly contact). More severe personality problems, current depressive symptoms, and self-harming before 12 March were associated with more frequent consultations. CONCLUSION: The survey confirms severe, enhanced levels of mental distress among patients receiving telephone-based consultations as the main alternative to specialized PD treatment during the COVID-19 shutdown. The most vulnerable patients received more frequent consultations and self-destructive actions did not increase.

Subjective experience of the origin and development of avoidant personality disorder.

OBJECTIVE: To better understand how persons diagnosed with avoidant personality disorder (AVPD) make sense of the origin and development of their current everyday struggles. METHODS: Persons with AVPD (N = 15) were interviewed twice using semi-structured qualitative interviews, which were analyzed through interpretative-phenomenological analysis. Persons with the first-hand experience of AVPD were included in the research. RESULTS: The superordinate theme, "a story of becoming forlorn," encompassed three main themes: "it goes all the way back to when I was little," "there was a distance between others and me," and "transitions made it worse." CONCLUSIONS: Though the results are not necessarily specific to AVPD, the findings clarify how people with AVPD can make sense of their current struggles by constructing developmental life stories in the interplay between themselves as persons and the growing demands of their social world. Furthermore, childhood relational vulnerabilities may challenge the ongoing development of social cognition and skills.

Measuring Personality Problems in Patients With Substance Use Disorders: A Cross-Sample Validation.

Objective: Co-occurrence of substance use disorder and personality disorder (PD) is associated with greater functional impairment and mutual deterioration of the prognosis. More information is needed about the extent of personality problems in substance use disorder patients and when these problems can be assessed in a reliable way. The aim of this study was to compare the levels and scale reliability of (mal)adaptive personality functioning in four different samples and to discuss the possible clinical implications. Methods: Personality problems were assessed using the self-report Severity Indices of Personality Problems (SIPP) questionnaire in four samples: (a) 136 patients in the detoxification phase, (b) 187 patients with substance use disorder in long-term inpatient treatment, (c) 1,399 patients with PD in day and outpatient treatment, and (d) a community population of 935 respondents. Scale reliability of the SIPP facets was computed for each sample and levels of personality problems were compared among samples. Results: The scale reliability was acceptable for most of the SIPP facets in both substance use disorder samples. The substance use disorder samples had scores on SIPP that reflected greater personality dysfunction compared with the general community population and at a level similar to the PD population. Conclusions: SIPP appears to be a promising instrument for assessing personality pathology in substance use disorder treatment. The finding of high levels of maladaptive personality functioning in substance use disorder populations challenges the clinical management of the substance use disorder patient group and supports the development of integrated treatment approaches.

Struggling to be a person: Lived experience of avoidant personality disorder.

OBJECTIVE: To better understand the subjective lived experience of persons diagnosed with avoidant personality disorder (AVPD). METHODS: Persons with an AVPD (N = 15) were interviewed twice with semistructured qualitative interviews and analyzed through interpretative-phenomenological analysis. Persons with first-hand experience of AVPD were included in the research process. RESULTS: The superordinate theme, "struggling to be a person," encompassed two main themes. The first, "fear and longing," incorporated the subthemes "longing for connection," "dreading to get close" and "being alone, for better or for worse." The second main theme, "a doubting self," included the subthemes "feeling insecure" and "searching for a sense of self." CONCLUSIONS: The findings shed light on how the reflexive selves of people with AVPD might struggle with sense-making, sense of agency, and identity. This study underscores how impaired tacit knowledge of social behavior can hamper the process of being a person in relation to others.

Contours of a causal feedback mechanism between adaptive personality and psychosocial function in patients with personality disorders: a secondary analysis from a randomized clinical trial.

BACKGROUND: Patients with personality disorders commonly exhibit impairment in psychosocial function that persists over time even with diagnostic remission. Further causal knowledge may help to identify and assess factors with a potential to alleviate this impairment. Psychosocial function is associated with personality functioning which describes personality disorder severity in DSM-5 (section III) and which can reportedly be improved by therapy. METHODS: The reciprocal association between personality functioning and psychosocial function was assessed, in 113 patients with different personality disorders, in a secondary longitudinal analysis of data from a randomized clinical trial, over six years. Personality functioning was represented by three domains of the Severity Indices of Personality Problems: Relational Capacity, Identity Integration, and Self-control. Psychosocial function was measured by Global Assessment of Functioning. The marginal structural model was used for estimation of causal effects of the three personality functioning domains on psychosocial function, and vice versa. The attractiveness of this model lies in the ability to assess an effect of a time - varying exposure on an outcome, while adjusting for time - varying confounding. RESULTS: Strong causal effects were found. A hypothetical intervention to increase Relational Capacity by one standard deviation, both at one and two time-points prior to assessment of psychosocial function, would increase psychosocial function by 3.5 standard deviations (95% CI: 2.0, 4.96). Significant effects of Identity Integration and Self-control on psychosocial function, and from psychosocial function on all three domains of personality functioning, although weaker, were also found. CONCLUSION: This study indicates that persistent impairment in psychosocial function can be addressed through a causal pathway of personality functioning, with interventions of at least 18 months duration.

Favourable outcome of long-term combined psychotherapy for patients with borderline personality disorder: Six-year follow-up of a randomized study.

OBJECTIVE: This study reports the six-year follow-up data of patients with borderline personality disorder (BPD) who participated in the Ullevål Personality Project (UPP), a randomized clinical study comparing outpatient individual psychotherapy (OIP) with a long-term combination programme (CP) comprising short-term day-hospital treatment followed by outpatient combined group and individual psychotherapy. METHODS: For 52 patients, outcomes were evaluated after 8 months, 18 months, 3 years, and 6 years based on a wide range of clinical measures, such as symptom severity, psychosocial functioning, personality functioning, and Axis-I and II diagnoses. RESULTS: At the six-year follow-up, patients in the CP condition reported significantly greater reduction of symptom distress and improvements in the personality functioning domains Identity Integration and Self-control compared with patients allocated to OIP. Patients in the CP also had a more favourable long-term course of psychosocial functioning. There were no differences between treatment conditions in outcomes of interpersonal functioning and self-esteem. CONCLUSIONS: Long-term psychotherapy in a combination programme seems favourable for BPD patients. In this study, patients who received combined treatment fared better on crucial parameters than patients who received individual therapy. Of particular importance are the positive effects on fundamental borderline problem areas like Identity Integration and Self-control.

Is reflective functioning associated with clinical symptoms and long-term course in patients with personality disorders?

OBJECTIVE: Mentalization is the capacity to understand behavior as the expression of various mental states and is assumed to be important in a range of psychopathologies, especially personality disorders (PDs). The first aim of the present study was to investigate the relationship between mentalization capacity, operationalized as reflective functioning (RF), and clinical manifestations before entering study treatment. The second aim was to investigate the relationship between baseline RF and long-term clinical outcome both independent of treatment (predictor analyses) and dependent on treatment (moderator analyses). METHODS: Seventy-nine patients from a randomized clinical trial (Ullevål Personality Project) who had borderline and/or avoidant PD were randomly assigned to either a step-down treatment program, comprising short-term day-hospital treatment followed by outpatient combined group and individual psychotherapy, or to outpatient individual psychotherapy. Patients were evaluated on variables including symptomatic distress, psychosocial functioning, personality functioning, and self-esteem at baseline, 8 and 18months, and 3 and 6years. RESULTS: RF was significantly associated with a wide range of variables at baseline. In longitudinal analyses RF was not found to be a predictor of long-term clinical outcome. However, when considering treatment type, there were significant moderator effects of RF. Patients with low RF had better outcomes in outpatient individual therapy compared to the step-down program. In contrast, patients in the medium RF group achieved better results in the step-down program. CONCLUSION: These findings indicate that RF is associated with core aspects of personality pathology and capture clinically relevant phenomena in adult patients with PDs. Moreover, patients with different capacities for mentalization may need different kinds of therapeutic approaches.

Step-down versus outpatient psychotherapeutic treatment for personality disorders: 6-year follow-up of the Ullevål personality project.

BACKGROUND: Although psychotherapy is considered the treatment of choice for patients with personality disorders (PDs), there is no consensus about the optimal level of care for this group of patients. This study reports the results from the 6-year follow-up of the Ullevål Personality Project (UPP), a randomized clinical trial comparing outpatient individual psychotherapy with a long-term step-down treatment program that included a short-term day hospital treatment followed by combined group and individual psychotherapy. METHODS: The UPP included 113 patients with PDs. Outcome was evaluated after 8 months, 18 months, 3 years and 6 years and was based on a wide range of clinical measures, such as psychosocial functioning, interpersonal problems, symptom severity, and axis I and II diagnoses. RESULTS: At the 6-year follow-up, there were no statistically significant differences in outcome between the treatment groups. Effect sizes ranged from medium to large for all outcome variables in both treatment arms. However, patients in the outpatient group had a marked decline in psychosocial functioning during the period between the 3- and 6-year follow-ups; while psychosocial functioning continued to improve in the step-down group during the same period. This difference between groups was statistically significant. CONCLUSIONS: The findings suggest that both hospital-based long-term step-down treatment and long-term outpatient individual psychotherapy may improve symptoms and psychosocial functioning in poorly functioning PD patients. Social and interpersonal functioning continued to improve in the step-down group during the post-treatment phase, indicating that longer-term changes were stimulated during treatment. TRIAL REGISTRATION: NCT00378248.

Patients with personality disorders in private specialist practice.

BACKGROUND: Private practitioners with contracts with the regional health authorities have an important place among the treatment options provided by the psychiatric specialist health service. Little information is available on the part such specialists in private practice should play in the treatment of patients with personality disorders. This study describes private practitioners' experiences with this patient group and the patients' satisfaction with the treatment. MATERIAL AND METHOD: 46 patients were referred to specialists in private practice as part of a treatment study of patients with personality disorders. 26 private practitioners took part. The patient population had extensive problems with a high level of symptoms, interpersonal difficulties and poor work functioning. A follow-up investigation of the patient group was conducted after three years. The therapists answered questionnaires about their own practices and the patient therapy. RESULTS: At the time of the three-year follow-up, a third of the patients were still in therapy. The median number of therapy sessions was 43 (range 2-258 hours). On the whole, the therapists found the treatments interesting from a professional point of view, and the majority of the patients were satisfied with the therapy. Some treatments were complicated by irregular attendance, substance abuse, risk of suicide or other serious symptoms. 29 % of the patients were dissatisfied with the therapy, particularly patients with substance abuse. INTERPRETATION: Psychotherapy with a specialist in private practice with a contract with regional health authorities allows for flexibility with respect to the duration of treatment for patients with a personality disorder. Substance abuse problems and acting-out behaviour present a challenge to treatment which may be difficult to handle in private practice. Treatment in private specialist practice presupposes the possibility of acute hospitalisation or access to other health services in the event of crises and complicating substance abuse.

The significance of connectedness: avoidant personality disorder patients' subjective experiences of change after attending a specialized treatment program.

Objectives: This study aimed to inquire into the subjective experiences and meaning-making of change of people diagnosed with avoidant personality disorder (AvPD) after attending a treatment program developed for AvPD. Methods: Eighteen AvPD patients were interviewed 1 year after completing their treatment using a semi-structured interview guide. The interviews were analyzed through reflexive thematic analysis. Results: Three main themes were found to capture the various subjective experiences of change. The first main theme "being more alive" included the subthemes "talking and listening together" and "opening up and grounding into myself." The second main theme was "still longing for more," and the third main theme "I cannot even manage therapy" included the subthemes "as if we were together" and "capitulation." Conclusion: Although these findings may not be specific to AvPD, they shed light on the importance of attending to the dynamic interplay of intersubjectivity, social motivations, and agency in a therapeutic context. Discovering a sense of agency within an interpersonal context in which the patient feels connected may lead to them opening up for development in accordance with their social motivational intentions.

Minding mentalizing - convergent validity of the Mentalization Breakdown Interview.

Objectives: Mentalizing difficulties are central to borderline personality disorder (BPD), have severe consequences, and are an explicit focus in mentalization-based treatment. The significance of mentalizing capacity as a predictor or mediator of change is however still uncertain due to a scarcity of research. The Mentalization Breakdown Interview (MBI) was developed as a time saving tool for studying psychotherapy processes and outcome in borderline pathology. This study aimed to investigate the convergent validity of reflective functioning (RF) ratings based on the MBI (MBI-RF) by a comparison with the gold standard, i.e., RF assessments based on the Adult Attachment Interview (AAI-RF). A secondary aim was to investigate how MBI-RF relates to core symptoms of BPD, levels of functional impairment and symptom distress compared with AAI-RF. Method: Forty-five patients with BPD or significant BPD traits were included. MBI-RF and AAI-RF were rated using the Reflective Functioning Scale. Levels of MBI-RF and AAI-RF and the correlation between the measures were calculated, as well as their associations with the Difficulties in Emotion Regulation Scale, Levels of Personality Functioning-Brief Form 2.0, Work and Social Adjustment Scale, Patient Health Questionnaire, Depression, Generalized Anxiety Disorder-7, self-harm, suicide attempts, and PD diagnostics. Results: The correlation between MBI-RF and AAI-RF was 0.79 (p<0.01), indicating high convergent validity. There were few significant associations between MBI-RF and AAI-RF and clinical measures. Conclusions: The study provides support for the convergent validity of the MBI as a BPD-focused RF assessment method. The MBI has the potential as a time saving, reliable and valid method to be applied in treatment research on patients with borderline pathology. The results indicate that measures of MBI-RF and AAI-RF are different from clinical symptoms. Clinical trial registration: ClinicalTrials.gov ID NCT04157907.

"It takes time to see the whole picture": patients' views on improvement in cognitive behavioral therapy and psychodynamic therapy after three years.

Introduction: There is a lack of qualitative research that retrospectively explores how patients with major depressive disorder view their improvement in psychotherapy. Methods: Fifteen patients who received short-term cognitive behavioral therapy and psychodynamic therapy were individually interviewed approximately three years after completing therapy. Results: Some patients had altered their views on therapy, especially those who initially were uncertain of how helpful therapy had been. They said they did not realize the extent and importance of their improvement in therapy before some time had passed, which can be explained by the surprising cumulative effects of seemingly small changes. Discussion: This should make retrospective qualitative research an important part of future psychotherapy research.

Health service costs and clinical gains of psychotherapy for personality disorders: a randomized controlled trial of day-hospital-based step-down treatment versus outpatient treatment at a specialist practice.

BACKGROUND: Day-hospital-based treatment programmes have been recommended for poorly functioning patients with personality disorders (PD). However, more research is needed to confirm the cost-effectiveness of such extensive programmes over other, presumably simpler, treatment formats. METHODS: This study compared health service costs and psychosocial functioning for PD patients randomly allocated to either a day-hospital-based treatment programme combining individual and group psychotherapy in a step-down format, or outpatient individual psychotherapy at a specialist practice. It included 107 PD patients, 46% of whom had borderline PD, and 40% of whom had avoidant PD. Costs included the two treatment conditions and additional primary and secondary in- and outpatient services. Psychosocial functioning was assessed using measures of global (observer-rated GAF) and occupational (self-report) functioning. Repeated assessments over three years were analysed using mixed models. RESULTS: The costs of step-down treatment were higher than those of outpatient treatment, but these high costs were compensated by considerably lower costs of other health services. However, costs and clinical gains depended on the type of PD. For borderline PD patients, cost-effectiveness did not differ by treatment condition. Health service costs declined during the trial, and functioning improved to mild impairment levels (GAF > 60). For avoidant PD patients, considerable adjuvant health services expanded the outpatient format. Clinical improvements were nevertheless superior to the step-down condition. CONCLUSION: Our results indicate that decisions on treatment format should differentiate between PD types. For borderline PD patients, the costs and gains of step-down and outpatient treatment conditions did not differ. For avoidant PD patients, the outpatient format was a better alternative, leaning, however, on costly additional health services in the early phase of treatment. TRIAL REGISTRATION: Clinical Trials NCT00378248.