Estimating the prevalence of borderline personality disorder in psychiatric outpatients using a two-phase procedure
Introduction
Borderline personality disorder (BPD) is a pervasive pattern of impulsiveness, self-destructive threats or behaviors, instability of moods, chaotic interpersonal relationships, and unstable sense of identity [1]. Patients with BPD have disproportionately high rates of health care resource utilization, high rates of self-injurious behavior, and a suicide rate of about 10% [2]. Since the advent of effective psychotherapies [3], it is imperative that outpatient clinics have an accurate estimate of the number of BPD patients in their care to plan resources and services.
The literature on the epidemiology of personality disorders is plagued by numerous methodological problems. First, the diagnostic criteria for BPD changed from the 1980 to the 1994 editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM), making early studies less relevant. Second, different diagnostic tools produce very different estimates of the prevalence of BPD. That is, compared with semistructured interviews, unstructured clinical assessments are less reliable, with more false negatives [4]. Conversely, self-report questionnaires produce too many false positives [5]. Third, research samples can be biased by clinical setting, access to treatment, help seeking, severity of illness, and comorbidity issues [6].
In the general population, looking at the studies with the broadest community random sample selection, the prevalence of BPD varied from 0.4% to 1.8%, with a pooled rate of 1.1% [7], [8], [9], [10]. In clinical samples, BPD is usually the most common personality disorder [11]. The rates of BPD in pre-1989 clinical interview psychiatric inpatients studies are 15% [11]. More recent inpatient studies with semistructured interviews have reported rates of 40% to 44% [12], [13].
The prevalence of BPD in outpatient samples varies depending on whether the clinic serves insured or uninsured patients or specialized populations. In outpatient samples, the rates of BPD have varied from 8% to 27%. The average prevalence across 8 pre-1989 clinical interview outpatient studies is 8% [11]. The average prevalence of BPD in outpatient studies that use self-report questionnaires is 27.7% to 30.3% [7], [14]. Recent semistructured interview studies have reported rates of 9.3% to 18% in consecutively enrolled subjects, with a pooled rate of 11.9% (n = 1657) [4], [15], [16], [17]. These 4 studies were conducted in a catchmented clinic serving a more affluent and educated part of the city, psychoanalysis applicants, and university clinics where patients were insured.
The 2-phase procedure (ie, screening with a self-report questionnaire and then interviewing those who screened positive) is an efficient methodology to identify cases of personality disorder. Nussbaum and Rogers [18] screened an inpatient forensic population with the Structured Clinical Interview for DSM-IV Personality Disorders–Patient Questionnaire (SCID-II-PQ) [19], followed by the Structured Clinical Interview for DSM-IV Personality Disorders (SCID--II) interview. They obtained a 2.4% false-negative rate of BPD and a 30.5% false-positive rate of BPD. Lenzenweger et al [5] screened university students with the Personality Disorder Examination (PDE) self-report screen, followed by the PDE interview. They obtained a 0% false-negative rate and an 84.3% false-positive rate for all the personality disorders. Thus, self-report questionnaires perform remarkably well in screening for personality disorders, as very few cases are missed [18].
The goal of the present study was to estimate the point prevalence of BPD in a general adult outpatient university clinic by screening with the BPD section of the SCID-II-PQ and then assessing the positive cases with the Revised Diagnostic Interview for Borderlines (DIB-R) [20]. The DIB-R has been used extensively to diagnose BPD, but never in prevalence studies. It is time consuming (1 hour) and requires substantial clinical experience to administer and score [20].
Section snippets
Methodology
The subjects were the 360 patients registered on May 1, 2005, in a general adult outpatient university clinic, catchmented to serve the downtown third of an industrial city of 500 000. All patients had government health insurance, regardless of social class. The study was approved by the hospital research ethics board. After giving informed consent, patients were screened with the BPD criteria from the DSM-IV version of the SCID-II-PQ. The SCID-II is a widely used instrument that closely adheres
Statistical analysis
We surveyed the whole clinic (n = 360) cross-sectionally to estimate the point prevalence of BPD in an outpatient clinic. The prevalence estimates were expressed as percentages (95% confidence intervals [CIs]). Descriptive statistics in phase 2 were reported by count (percentage) for categorical variables and mean (SD) or median (minimum, maximum) for continuous variables. We asked whether demographic variables would distinguish the more severely ill DIB-R–positive subjects from the
Results
Three hundred sixty patients were registered in the general clinic on the start date. Fig. 1 summarizes the flow of patients in the study. One hundred twenty-one were not screened with the SCID-II-PQ, resulting in a completion rate of 66.4% (239/360). Lacking demographic data, we cannot determine whether those who completed the screening differed significantly from those who did not. In a post hoc interview, 21.5% (26/121) of the noncompleters were considered to have BPD by their therapists
Discussion
A 22.6% point prevalence of BPD in a general adult outpatient clinic is somewhat higher than reported by other semistructured interview studies in the literature. Our study is unique in that we surveyed the entire clinic population at one time, rather than consecutive admissions. Our patients were diagnosed by 2 instruments: the SCID-II-PQ and the DIB-R. To our knowledge, the DIB-R has not been used before in a prevalence study of a clinical population.
The demographics of our sample are
Acknowledgment
This research was partially supported by a grant from the Department of Psychiatry and Behavioural Neurosciences at McMaster University.
The authors would like to thank all the clinical staff that made this study possible: Dr Alan Eppel, Michelle Carrigan, Debbie Fournier, Donna Gorle, Betty-Lou Homer, Irene Solivere, Sandy Yuen, and Karen Wisdom.
References (29)
- et al.
A 27 year follow-up of patients with borderline personality disorder
Compr Psychiatry
(2001) Diagnostic and statistical manual of mental disorders
(1994)Cognitive behavioral treatment of borderline personality disorder
(1993)- et al.
Differences between clinical and research practices in diagnosing borderline personality disorder
Am J Psychiatry
(1999) - et al.
Detecting personality disorders in a nonclinical population: application of a 2-stage procedure for case identification
Arch Gen Psychiatry
(1997) Epidemiology of personality disorders
- et al.
Prevalence of DSM-III personality disorders in the community
Soc Psychiatry Psychiatr Epidemiol
(1989) - et al.
DSM-III personality disorders in the community
Am J Psychiatry
(1994) - et al.
Estimating the prevalence of borderline personality disorder in the community
J Personal Disord
(1990) - et al.
The prevalence of personality disorders in a community sample
Arch Gen Psychiatry
(2001)
Epidemiology of borderline personality disorder
Hosp Community Psychiatry
Frequency of personality disorders in two age cohorts of psychiatric inpatients
Am J Psychiatry
Patterns of comorbidity among DSM-III-R personality disorders
Psychopathology
Personality traits and disorders among psychiatric outpatients and normal subjects on the basis of the SCID screen questionnaire
Nord J Psychiatry
Cited by (134)
Treatment outcomes of Veteran men in a comprehensive dialectical behavior therapy program: Characterizing sex differences in symptom trajectories
2023, Journal of Psychiatric ResearchBorderline personality disorder
2023, Encyclopedia of Mental Health, Third Edition: Volume 1-3Effects of pharmacological treatments on neuroimaging findings in borderline personality disorder: A review of FDG-PET and fNIRS studies
2022, Journal of Affective DisordersDevelopmental trajectories of anger and sadness dysregulation in childhood differentially predict later borderline symptoms
2023, Development and PsychopathologySex and gender in treatment response to dialectical behaviour therapy: current knowledge, gaps, and future directions
2022, Cognitive Behaviour TherapistOutcomes for pregnant women with Borderline Personality Disorder who attended a specialist antenatal service
2024, Australasian Psychiatry
Earlier versions of this work were displayed as posters at the McMaster University Department of Psychiatry and Behavioural Neurosciences, 18th Annual Research Day, Hamilton, Ontario, Canada, April 2006, and the Canadian Association for Suicide Prevention annual conference, Toronto, Ontario, Canada, October 2006.