Background: Self-harm is prevalent in prison populations and is a well-established risk factor for suicide. Researchers typically rely on self-report to measure self-harm, yet the accuracy and predictive value of self-report in prison populations is unclear. Using a large, representative sample of incarcerated men and women, we aimed to examine the level of agreement between self-reported self-harm history and historical medical records, and investigate the association between self-harm history and medically verified self-harm after release from prison.
Methods: During confidential interviews with 1315 adults conducted within 6 weeks of expected release from 1 of 7 prisons in Queensland, Australia, participants were asked about the occurrence of lifetime self-harm. Responses were compared with prison medical records and linked both retrospectively and prospectively with ambulance, emergency department and hospital records to identify instances of medically verified self-harm. Follow-up interviews roughly 1, 3 and 6 months after release covered the same domains assessed in the baseline interview as well as self-reported criminal activity and contact with health care, social and criminal justice services since release.
Results: Agreement between self-reported and medically verified history of self-harm was poor, with 64 (37.6%) of 170 participants with a history of medically verified self-harm disclosing a history of self-harm at baseline. Participants with a medically verified history of self-harm were more likely than other participants to self-harm during the follow-up period. Compared to the unconfirmed-negative group, the true-positive (adjusted hazard ratio [HR] 6.2 [95% confidence interval (CI) 3.3-10.4]), false-negative (adjusted HR 4.0 [95% CI 2.2-6.7]) and unconfirmed-positive (adjusted HR 2.2 [95% CI 1.2-3.9]) groups were at increased risk for self-harm after release from prison.
Interpretation: Self-reported history of self-harm should not be considered a sensitive indicator of prior self-harm or of future self-harm risk in incarcerated adults. To identify those who should be targeted for preventive strategies, triangulation of data from multiple verifiable sources should be performed whenever possible.
Rohan Borschmann, PhD, DClinPsych, Jesse T. Young, MPH, Paul Moran, MD, Matthew J. Spittal, PhD, Kathryn Snow, MPH, Katherine Mok, PhD, Stuart A. Kinner, PhD
CMAJ Open, September 11, 2017