title: Assessing the risk of self-harm in an adult offender population: an incidence cohort study.
abstract: BACKGROUND
  Self-harm is common among prisoners, particularly female prisoners. In 2007, concerned about the rising incidence, the prison service introduced a care-planning system called Assessment, Care in Custody, and Teamwork (ACCT). To date, it does not incorporate a standardised diagnostic test to estimate the risk of future self-harm.
  
  
  OBJECTIVE
  To identify potential screening instruments, or items from those instruments, to predict the risk of self-harm among prisoners.
  
  
  METHODS
  Prisoners who had been assigned to an ACCT during the recruitment period.
  
  
  METHODS
  A multistage prospective cohort study. Following a pilot study, instruments were administered to prisoners by interview at baseline, and followed up for 6 months (or until point of release if this was sooner) to ascertain self-harm status. Instruments were assessed for unidimensionality, scalability (Mokken) and quantitative structure (Rasch). Area under the curve (AUC) analysis was used to examine the ability of instruments and/or their items to predict future self-harm. Cox proportional hazards regression models were used to examine the multivariate predictive ability of the scales and various sociodemographic and sentencing factors.
  
  
  METHODS
  Three prisons (including one women's prison) in northern England.
  
  
  METHODS
  A set of standardised questionnaires, including the Prison Screening Questionnaire (PriSnQuest), Revised Borderline Symptom List-23 (frequency-based responses) (BSL-23-F), Self-Harm Inventory (SHI), Patient Health Questionnaire (PHQ-9) and the Clinical Outcomes in Routine Evaluation - Outcome Measure (CORE-OM), together with sociodemographic and sentencing data.
  
  
  RESULTS
  In total, 450 prisoners consented to participate in the study, of whom 26% were female. The mean age of participants was 31.2 years. Over half of male prisoners recruited were on remand, compared with just over one-fifth (22.6%) of female prisoners. The average tariff of those sentenced was 41 months, of which 14.7 months, on average, had been served. Just over one-third of ACCTs had been initiated because of a known self-harm event, and over one-quarter (27.8%) of participants self-harmed during the follow-up period. Thus, almost half (46.7%) of those entered into the study were reported to have self-harmed, either from their index ACCT, or subsequently, or both. Cutting was the most frequent behaviour (51%). All screening instruments showed some evidence of unidimensionality, and four out of five showed scaling criteria consistent with ordinal scaling, so verifying the validity of the cut points. However, many showed gender bias and failure to fit the Rasch measurement model. While a resolution was made in most cases, both ordinal raw scores and latent interval scale estimates failed to show predictive value when applied within AUC analysis (0.491-0.566) or adjusted Cox proportional hazards models. However, good predictive values were shown for gender-specific sets of items, thus providing easily applied screening indexes.
  
  
  CONCLUSIONS
  While four out of five potential screening instruments were found to have acceptable psychometric properties within this setting, their predictive validity of all instruments was poor under AUC analysis. Gender-specific item sets were put together to form two screening indexes with formative indicators which gave reasonable AUC values, particularly so for females. The indexes provide identification of low-medium-high risk of self-harm, and so may help to inform potential care pathways and decisions to sign prisoners off from the ACCT. Future work should concentrate on refining a set of predictive screening items among different offender populations and investigating the time point at which this set of items should be administered. Future work may also look at the different magnitudes of risk as indicators for care pathways.
  
  
  BACKGROUND
  The National Institute for Health Research Health Technology Assessment programme.
authors.affiliation: Academic Department of Rehabilitation Medicine, Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Horton
authors.affiliation: HMP Leeds Health Care Department, Leeds, UK.
authors.forename: Nat
authors.initials: N
authors.lastname: Wright
authors.affiliation: Department of Sociology and Criminology, University of Durham, , UK.
authors.forename: Wendy
authors.initials: W
authors.lastname: Dyer
authors.affiliation: Clinical Trials Research Unit, Leeds Institute of Clinical Trials Research, University of Leeds, Leeds, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Wright-Hughes
authors.affiliation: Clinical Trials Research Unit, Leeds Institute of Clinical Trials Research, University of Leeds, Leeds, UK.
authors.forename: Amanda
authors.initials: A
authors.lastname: Farrin
authors.affiliation: HMP Leeds Health Care Department, Leeds, UK.
authors.forename: Zanib
authors.initials: Z
authors.lastname: Mohammed
authors.affiliation: North East Offender Health Commissioning Unit, Durham University Science Park, County Durham, UK.
authors.forename: Jamie
authors.initials: J
authors.lastname: Smith
authors.affiliation: Brampton Primary Care Medical Centre, Rotherham, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Heyes
authors.affiliation: Department of Health Sciences, University of York, York, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Gilbody
authors.affiliation: Academic Department of Rehabilitation Medicine, Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Tennant
mesh_terms: D000293:Adolescent; D000328:Adult; D057237:Criminals / Q000523:psychology / Q000706:statistics & numerical data*; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011330:Prisons / Q000706:statistics & numerical data*; D011446:Prospective Studies; D011594:Psychometrics; D015203:Reproducibility of Results; D018570:Risk Assessment; D016728:Self-Injurious Behavior / Q000175:diagnosis* / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D055815:Young Adult