Exercising an injury on purpose: relationships with borderline personality symptomatology.

To the Editor: Borderline personality disorder (BPD) is a personality dysfunction characterized by repetitive self-harm behavior. In this study, we examined whether having intentionally exercised an established injury, a potential form of self-harm behavior, might be associated with borderline personality symptomatology. Method. To maximize the size of the current sample for investigation, we compiled 4 datasets that were collected over a 2-year period (2009–2011),1–4 all consisting of men and women aged 18 years or older consecutively recruited from the same internal medicine outpatient clinic staffed predominantly by resident providers. For each dataset, the recruiter informally assessed and excluded individuals with symptoms of a severity to preclude the completion of a survey. (Few were actually excluded, most because of severe illness and/or language difficulties.) Of the resulting 1,511 patients, 496 were male, 1,014 were female, and 1 did not indicate sex. Ages ranged from 18 to 97 years (mean [SD] = 50.83 [15.71] y), and 87.6% were white. During clinic hours, each incoming patient was approached by a research assistant, who assessed exclusion criteria, reviewed the focus of the project, and invited candidates to participate by completing a multipage survey. In addition to demographic queries, we examined borderline personality symptomatology through 2 self-report measures—the BPD scale of the Personality Diagnostic Questionnaire-4 (PDQ-4)5 and the Self-Harm Inventory (SHI),6 using the traditional cutoff scores of 5 or greater for both measures (ie, substantial borderline personality symptomatology). SHI item 19 asks, “Have you ever intentionally, or on purpose, exercised an injury to hurt yourself?” As the focus of the current investigation, this item was not included in the subsequent scoring of the SHI to determine borderline personality symptomatology status. These various projects were reviewed and exempted by 2 institutional review boards. Completion of the survey was assumed to be implied consent, which was explicitly clarified on the cover page of each survey booklet. Results. Of the 1,511 respondents, 44 (2.9%) indicated having intentionally exercised an injury to hurt themselves, and this rate did not differ significantly between men and women (χ2 = 0.83, P < .88). Point-biserial correlation coefficients revealed that those who endorsed this item tended to be younger (r = –0.14, P < .001) and scored higher on the PDQ-4 (r = 0.24, P < .001) and the SHI (r = 0.37, P < .001). Similarly, when compared to respondents who denied ever having exercised an injury on purpose, those who did were more likely to exceed the clinical cutoff score for borderline personality symptomatology on both the PDQ-4 (50.0% vs 13.9%, χ2 = 43.87, P < .001) and the SHI (86.4% vs 15.0%, χ2 = 153.52, P < .001). The potential limitations of this study include the self-report nature of all data, possible repeat patients in the database (less likely due to the 2-year time span), and the overinclusiveness of the borderline personality symptomatology measures (ie, risk of false positives). However, to our knowledge, this is the first report to associate exercising an injury on purpose with borderline personality symptomatology—a seemingly relevant finding for all professionals involved in health care.