People in prison often present with complex needs, including mental health problems, and prisoners are a high risk population for suicide and self-harming behaviours (Fazel et al., 2016).
Self-injurious and suicidal behaviour is a large and growing problem in UK prisons. In July 2020 the Ministry of Justice reported a ‘record high’ of self-harm incidents in the twelve months leading to March 2020, showing an increase of 11% from the previous 12 months (Ministry of Justice, 2020).
This is especially pertinent at the time of writing, as we are currently going through an international pandemic, meaning that those who are already incarcerated are likely experiencing increased feelings of loneliness and isolation due to the temporary suspension of prison visits and more time spent in cells. Reports from prison mental health staff suggest these new temporary regulations could lead to an exacerbation of symptoms among those with prior mental health difficulties, and deterioration in those without pre-existing conditions (Kothari et al., 2020).
Relatively little is known about the underlying mechanisms for self-injurious behaviours amongst prisoners, and whilst previous research has examined a range of individual and environmental correlates of self-harm in prisoners, findings are inconsistent. Hence Favril and colleagues’ timely report that aimed to “synthesise the evidence and assess the risk factors associated with self-harm in prison” (Favril et al., 2020).
The authors searched four electronic databases (PubMed, Embase, Web of Science, and PsycINFO) from database inception to Oct 31, 2019 to identify relevant observational studies on risk factors for self-harm in prisoners. They screened references of included papers and other relevant systematic reviews, conducted targeted searches to identify additional studies by first author names, and contacted experts for unreported or ongoing studies. No language restrictions were set. The review was prospectively registered on PROSPERO (CRD42018087915) and was reported using PRISMA guidelines.
The reviewers applied the following criteria for included studies:
- Cross-sectional, case-control, or cohort in design and included predominantly adult prisoners;
- Based on general prison populations;
- Included self-harm within prison as the outcome measure; and
- Provided data for an appropriate control or comparison group of unselected prisoners who did not self-harm in prison.
Qualitative or ecological studies were excluded, in addition to those that reported on: lifetime measures of self-harm; selected samples of prisoners; and those with an inappropriate comparison group (e.g. not based on general prison populations).
Data were independently extracted by two researchers, who used standardised extraction sheets that were cross-checked for consistency. Authors pooled effect sizes as odds ratios using random effects models for each risk factor examined in at least three distinct samples. Study quality was assessed using the Newcastle-Ottawa Scale for cohort and case-control studies, and the researchers examined between-study heterogeneity and presence of potential publication bias.
The meta-analysis synthesised data from almost fifty years of research, and following a rigorous study selection process the researchers identified 35 independent studies (reported in 38 articles) from twenty countries comprising a total of 663,735 prisoner participants. Overall, 18 (51%) of the 35 studies included were judged to be of high quality and four (11%) were categorised as being of low methodological quality.
The authors took a broad definition of self-harm as “any act of intentional self-poisoning or self-injury irrespective of the degree of suicidal intent or underlying motive”, and identified three separate outcomes:
- suicide attempt,
- and non-suicidal self-injury.
Risk factors were grouped into five categories:
- and historical.
Across the 40 risk factors examined, the strongest associations with self-harm in prison were found for clinical factors, including:
- suicide-related antecedents, including current or recent suicidal ideation (Odds Ratio 13·8, 95% CI 8·6 to 22·1; I²=49%),
- lifetime history of suicidal ideation (8·9, 6·1 to 13·0; I²=56%),
- and previous self-harm (6·6, 5·3 to 8·3; I²=55%)
Strong associations were also identified with:
- psychiatric diagnosis (8·1, 7·0 to 9·4; I²=0%)
- prison-specific environmental factors, such as:
- solitary confinement (5·6, 2·7 to 11·6; I²=98%),
- disciplinary infractions (3·5, 1·2 to 9·7; I²=99%),
- and experiencing sexual or physical victimisation while in prison (3·2, 2·1 to 4·8; I²=44%).
All historical life events measured (e.g. childhood abuse, or family history of suicide) were associated with self-harm; sociodemographic and criminological factors were only modestly associated with self-harm in prison. The leading risk factors for each of the five categories are presented below.
|Category||Leading risk factor|
|Clinical||Current suicidal ideation|
|Historical||Childhood sexual abuse|
|Criminological||Being sentenced for ≥ 5 years|
The authors identified five categories of risk factors that are associated with self-harm in prison; their findings indicate strong effects for modifiable clinical and custodial factors, moderate effects for historical factors, and smaller effects for sociodemographic and criminological factors.
Many of the identified risk factors are similar to those found for self-harm in the general population.
Contrary to many other research studies, Favril and colleagues did not find a statistical difference in self-harm behaviour between male and female prisoners, although women did have an increased risk of self-harm.
Strengths and limitations
This review has many merits; it provides the first quantitative meta-synthesis of factors associated with self-harm in prison that boasts large population numbers and the inclusion of previously unavailable data.
However, the authors noted several limitations:
- the scope of the search;
- overestimating risk estimates;
- scarcity of prospective studies that are required to explore whether risk factors predict self-harm during the course of imprisonment (reported associations could be due to reverse causality);
- frequency of self-harm was not explored, where risk factors might differ in separate incidences (i.e. first episode of self-harm and repeat self-harm);
- reliance on self-report of self-harm, which might underestimate the prevalence of self-harm in custody;
- some variables associated with self-harm showed high heterogeneity among risk estimates, so the pooled estimates should be interpreted with caution;
- lack of inclusion of institutional variables (e.g. prison size); and
- the authors identified no studies from low-income and middle-income countries.
Additionally, the authors use a broad definition of self-harm, combining non-suicidal self-injury and suicide attempt into a single self-harm outcome. Whilst this is consistent with policy and reporting in many prison jurisdictions, due to high co-occurrence of both behaviours and previously identified overlapping risk factors, it would be interesting to look at these as separate outcomes as the authors noted a disparity between previously identified risk-factors for suicide in custody (e.g. single-cell occupancy; Fazel et al., 2008) and their findings relating to self-harm.
Implications for practice
This systematic review and meta-analysis helps us understand the risk factors for self-harm in a prison environment, and provides evidence of modifiable risk factors that could help improve prevention efforts in this high-risk population. The authors identify the main clinical implication, that is, “the contribution of both individual and environmental risk factors to self-harm in prison” in that “prisoners might import a vulnerability for self-harm into prison that might interact with custody-specific stressors, thereby increase the likelihood of self-harming in prison” (Favril et al., 2020).
These findings emphasise the need for a whole-prison approach and multiagency collaboration in the prevention of self-harm and could identify suitable groups for future interventions and treatment trials, and assist decision makers in allocating limited prison resources.
Statement of interests
Favril, L., Yu, R., Hawton, K. and Fazel, S. (2020) Risk factors for self-harm in prison: a systematic review and meta-analysis Lancet Psychiatry, 7(8), pp. 682-691, DOI: https://doi.org/10.1016/S2215-0366(20)30190-5
Fazel, S., Cartwright, J., Norman-Nott, A. and Hawton, K. (2008). ‘Suicide in prisoners: a systematic review of risk factors‘, Journal of Clinical Psychiatry, 69(11), pp. 1721-31, DOI, https://pubmed.ncbi.nlm.nih.gov/19026254/
Fazel, S., Hayes, A. J., Bartellas, K., Clerici, M. and Trestman, R. (2016). ‘Mental health of prisoners: prevalence, adverse outcomes, and interventions’, The Lancet Psychiatry, 3(9), pp. 871-881, DOI: 10.1016/s2215-0366(16)30142-0
Kothari, R., Forrester, A., Greenberg, N., Sarkissian, N. and Tracy, D. K. (2020). ‘COVID-19 and prisons: Providing mental health care for people in prison, minimising moral injury and psychological distress in mental health staff‘, Medicine, Science and the Law, 60(3), pp. 165–168, DOI: https://doi.org/10.1177/0025802420929799
Ministry of Justice (2020). Safety in Custody Statistics, England and Wales: Deaths in Prison Custody to June 2020 Assaults and Self-harm to March 2020: Ministry of Justice. Available at: www.gov.uk/government/collections/safety-in-custody-statistics.