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Published · Empirical article

Borderline Personality Disorder Does Not Predict Treatment Outcome in a Partial Hospital Program Independent of Internalizing and Harmful Substance Use Dimensions

Gilbert, K. J., Conway, C. C., Snorrason, I., Beard, C., Moscardini, E., & Björgvinsson, T.

2025Personality Disorders: Theory, Research, and Treatment

The central contribution

Broad dimensions of psychopathology, especially internalizing, accounted for much of the prognostic information traditionally attributed to a borderline diagnosis.

In 2,625 partial-hospital patients, the study compared borderline features with internalizing and harmful substance-use dimensions as predictors of change in symptoms, functioning, and quality of life.

Analytic logic

The prognostic question changes when shared variance is modeled.

A diagnosis can summarize a recognizable clinical pattern while still sharing substantial information with broader dimensions. The analysis asked what each predictor contributed after that overlap was taken seriously.

Original website illustration showing overlapping diagnostic dimensions and shared clinical information
2,625partial-hospital patients
3outcome domains
Internalizingstrongest consistent predictor

Why the work matters

Three ideas to carry forward.

The full methods and interpretation remain in the official article.

01

Prediction is not the same as description

A diagnosis may be clinically meaningful without being the most efficient stand-alone predictor of treatment response.

02

Shared variance matters

The apparent prognostic role of BPD changed when internalizing and harmful substance use were considered in the same model.

03

Assessment should match the decision

The useful question is not only whether a diagnosis is present, but which dimensions supply information relevant to the clinical outcome being predicted.

Formal citation

Gilbert, K. J., Conway, C. C., Snorrason, I., Beard, C., Moscardini, E., & Björgvinsson, T. (2025). Borderline personality disorder does not predict treatment outcome in a partial hospital program independent of internalizing and harmful substance use dimensions. Personality Disorders: Theory, Research, and Treatment.