Self-harm risk screening on prison entry: assessing the predictive validity of self-harm history and recent ideation...

Rates of self-harm are elevated in prison, and there is limited evidence to support the efficacy of brief risk screening at reception to predict and prevent self-harm. This study aims to examine the predictive validity of the self-harm/suicide screening items embedded in a prison mental health screening tool from two key domains strongly associated with risk: previous suicidal/self-harm behaviour, and recent ideation.

A sample of men and women were screened on entry to prison, with eight screening items covering the two key domains of risk. Follow-up data on self-harm incidents were collected for 12 months post-screening. The predictive validity of individual screening items, item combinations and cumulative screening score was examined for the overall sample and for men and women separately.

Individual screening items across the two domains were all strongly associated with self-harm in the follow-up period, with odds ratios varying from 2.34 to 9.24. The predictive validity of both individual items, item scores and item combinations demonstrated high specificity but low to moderate sensitivity, and modest area under the curves (AUCs). Predictive validity was generally better for men than women; however, differences were not statistically significant.

Identifying those at risk of self-harm in prisons remains challenging and brief universal screening at prison entry should be only one component of a broader prison risk assessment and management strategy.

To the best of the authors' knowledge, this study is one of very few to prospectively examine self-harm behaviour following risk screening. Predictive validity was examined in a representative sample of individuals in custody, and for men and women separately.