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The BSL-23 is the short form of Bohus’s Borderline Symptom List — the self-report severity tracker used in DBT and similar borderline-focused protocols to measure trajectory across treatment. It’s descriptive, not diagnostic. A high score doesn’t make a BPD diagnosis; a downward trend across sessions is the signal you’re after. Twenty-three items, one week look-back, free for academic and clinical use under CC-BY.

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What it measures

Past-week severity of borderline-specific symptoms across seven implicit domains:
  • Self-perception
  • Affect regulation
  • Self-destructive impulses
  • Dysphoria
  • Loneliness and emptiness
  • Intrusions
  • Hostility
The 23 items don’t map cleanly to seven distinct subscales — Bohus designed the short form for a single severity total. Use the total score and watch the trajectory.

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When to use it

  • Intake for borderline-focused work to establish a severity baseline.
  • Every 2-4 weeks during DBT or other borderline protocols to track trajectory.
  • Pre/post a discrete protocol phase (DBT skills modules, brief DBT, modified EMDR for CPTSD).
  • Outcome documentation at discharge.

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How clients fill it out

Twenty-three items rated 0-4 (Not at all → Very strong) over the past week. Five to seven minutes. Reading level grade 7-8.

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Scoring and severity cutoffs

Sum of all 23 items. Range 0-92.

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Bands

Bands are derived from the canonical per-item mean thresholds in Kleindienst 2020’s BSL-23 validation work — the original instrument is sometimes interpreted on a 0-4 mean scale rather than a sum, and the Rivet bands translate the mean cuts back to the sum scale.

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Self-harm / suicidality items

Items 5 (self-harm thoughts), 7 (right to live), 12 (self-punishment), and 18 (fascination with death) form a separate flagged subscale. Any score ≥ 1 on any of these surfaces a “self-harm / suicidality / death-fascination endorsed — clinical evaluation indicated” label on the result.
The self-harm subscale flag is decision-support, not a complete risk assessment. When any of items 5, 7, 12, or 18 are endorsed, do a direct risk conversation with the client and pair with the C-SSRS at intake and at any inflection point. The BSL-23 alone is not sufficient for risk stratification.

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Clinical change

BPD severity moves slowly. A 5-10 point drop across a 12-week treatment period is in the range of effects reported in DBT outcome literature. A one-band shift (e.g. high → moderate) over a full course of treatment is the more clinically meaningful threshold for documentation.

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Use note

BSL-23 is descriptive, not diagnostic. It tells you how severe the borderline-spectrum experience is right now — it doesn’t make a BPD diagnosis. Positive borderline screening belongs with the MSI-BPD or a structured clinical interview. Use BSL-23 once a clinical frame is established to track severity over time.

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BSL-23 vs MSI-BPD

The BSL-23 is descriptive, not diagnostic, and that is a deliberate design choice rather than a limitation. It has no cutoff that says “borderline”; it produces a severity number for the past week that you can watch move across a course of DBT. Screening is the MSI-BPD’s job — ten yes/no items against the DSM criteria with a cutoff at 7, and a positive result meaning a structured interview is warranted. So they sit in sequence rather than competition: MSI-BPD to decide whether this is the right formulation, BSL-23 to track it once you’re working. Using the BSL-23 as a screen would be reading a number it isn’t producing.

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Is it free to use?

Yes. Published under a Creative Commons attribution licence by Bohus and colleagues.

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Citation

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 (BSL-23): development and initial data on psychometric properties.” Psychopathology, 42(1): 32-39. CC-BY academic/clinical use per Bohus 2009. Verbatim canonical wording.

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When not to use it

  • You’re doing a borderline differential without an established frame. Use MSI-BPD or a structured interview first.
  • The client is under 18. BSL-23 is validated in adult samples.
  • You want a measure of emotion regulation specifically. Use the DERS-18 instead — BSL-23 is broader.

DERS-18

Emotion regulation difficulties — narrower than BSL-23 and closer to the DBT skills frame.

ITQ

Complex PTSD measure for clients whose presentation crosses BPD and CPTSD.

C-SSRS

Suicide risk screener — pair with BSL-23 when self-harm items flag.