Borderline Symptom Test (BSL23)

The Borderline Symptom List – 23 (BSL-23) is a widely recognized, psychometrically validated self-report questionnaire designed to assess the severity of symptoms associated with borderline personality disorder (BPD). Developed by Martin Bohus and colleagues, the BSL-23 is the short form of the original 95-item Borderline Symptom List, created to provide a concise, reliable, and user-friendly measure for both clinical and research purposes. Its brevity and scientific rigor make it one of the most popular tools for monitoring BPD symptom severity and tracking treatment outcomes.

The BSL-23 contains 23 items covering key aspects of borderline symptomatology, including emotional instability, identity disturbance, interpersonal sensitivity, impulsivity, self-destructive urges, and dissociation. Respondents rate each statement based on their experiences over a specified time frame, typically the past week or month, using a 5-point Likert scale ranging from “not at all” to “very strong.” All items are scored in the same direction, meaning higher scores indicate greater symptom severity, simplifying interpretation for clinicians and researchers.

One of the BSL-23’s strengths is its validated psychometric properties. Research shows it has excellent internal consistency, test-retest reliability, and convergent validity with other measures of borderline personality disorder. Additionally, it is sensitive to change over time, making it an effective tool for monitoring treatment progress in psychotherapy or other clinical interventions. Clinicians often use the BSL-23 to identify symptom patterns, assess severity, and guide treatment planning, while researchers use it in studies exploring the etiology, course, and treatment of borderline personality disorder.

The BSL-23 is organized into several thematic subscales, although it is often used as a unidimensional measure. These subscales include Emotional Instability/Pain, Identity & Self-Disturbance, Interpersonal & Abandonment Sensitivity, Impulsivity & Destructive Urges, and Dissociation, Anger & Inner Tension. This structure allows clinicians to identify which areas are most affected in a given individual, providing a more nuanced understanding of symptom expression.

Because it is brief, reliable, and evidence-based, the BSL-23 is increasingly used in both mental health clinics and academic research. It is suitable for adults diagnosed with borderline personality disorder as well as for screening in clinical populations where BPD traits are suspected. Importantly, while the BSL-23 provides a clear measure of symptom severity, it is not a diagnostic tool on its own and should be used alongside comprehensive clinical assessment.

In summary, the BSL-23 is an essential instrument for anyone involved in the assessment or treatment of borderline personality disorder. Its combination of brevity, validated psychometric properties, and sensitivity to treatment effects makes it a gold-standard measure in both clinical and research settings. For clinicians, researchers, and mental health professionals, the BSL-23 provides a reliable, evidence-based approach to understanding and tracking the complex symptoms of borderline personality disorder over time.

References

• Bohus, M., Kleindienst, N., Limberger, M. F., Stieglitz, R.D., Domsalla, M., Chapman, A. L., Steil, R., Philipsen, A., & Wolf, M. (2009). The short version of the Borderline Symptom List (BSL23): Development and initial data on psychometric properties. Psychopathology, 42(1), 32–39. https://doi.org/10.1159/00017370
• Wolf, M., Limberger, M. F., Kleindienst, N., Stieglitz, R.D., Domsalla, M., Philipsen, A., & Bohus, M. (2009). Short version of the Borderline Symptom List (BSL23): Development and psychometric evaluation. Psychopathology. https://doi.org/10.1055/s00281104598
• Soler, J., Vega, D., FeliuSoler, A., Trujols, J., Soto, Á., Elices, M., & Pascual, J. C. (2013). Validation of the Spanish version of the Borderline Symptom List, short form (BSL23). BMC Psychiatry, 13, 139. https://doi.org/10.1186/1471244X13139