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A Prospective Cohort Study of Absconsion Incidents in Forensic Psychiatric Settings: Can We Identify Those at High-Risk?

Cullen AE, Jewell A, Tully J, Coghlan S, Dean K, Fahy T - PLoS ONE (2015)

Bottom Line: In multivariate analyses, four factors relating to offending and behaviour emerged as the strongest predictors of absconsion: history of sexual offending, previous absconsion, recent inpatient verbal aggression, and recent inpatient substance use.The weighted risk scale derived from these factors had moderate-to-good predictive accuracy (ROC area under the curve: 0.80; sensitivity: 067; specificity: 0.71), a high negative predictive value (0.91), but a low positive predictive value (0.34).Potentially-targetable recent behaviours, such as inpatient verbal aggression and substance use, are strong predictors of absconsion in forensic settings; the absence of these factors may enable clinical teams to identify unnecessarily restricted low-risk individuals.

View Article: PubMed Central - PubMed

Affiliation: Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.

ABSTRACT

Background: Incidents of absconsion in forensic psychiatric units can have potentially serious consequences, yet surprisingly little is known about the characteristics of patients who abscond from these settings. The few previous studies conducted to date have employed retrospective designs, and no attempt has been made to develop an empirically-derived risk assessment scale. In this prospective study, we aimed to identify predictors of absconsion over a two-year period and investigate the feasibility of developing a brief risk assessment scale.

Methods: The study examined a representative sample of 135 patients treated in forensic medium- and low-secure wards. At baseline, demographic, clinical, treatment-related, and offending/behavioural factors were ascertained from electronic medical records and the treating teams. Incidents of absconsion (i.e., failure to return from leave, incidents of escape, and absconding whilst on escorted leave) were assessed at a two-year follow-up. Logistic regression analyses were used to determine the strongest predictors of absconsion which were then weighted according to their ability to discriminate absconders and non-absconders. The predictive utility of a brief risk assessment scale based on these weighted items was evaluated using receiver operator characteristics (ROC).

Results: During the two-year follow-up period, 27 patients (20%) absconded, accounting for 56 separate incidents. In multivariate analyses, four factors relating to offending and behaviour emerged as the strongest predictors of absconsion: history of sexual offending, previous absconsion, recent inpatient verbal aggression, and recent inpatient substance use. The weighted risk scale derived from these factors had moderate-to-good predictive accuracy (ROC area under the curve: 0.80; sensitivity: 067; specificity: 0.71), a high negative predictive value (0.91), but a low positive predictive value (0.34).

Conclusion: Potentially-targetable recent behaviours, such as inpatient verbal aggression and substance use, are strong predictors of absconsion in forensic settings; the absence of these factors may enable clinical teams to identify unnecessarily restricted low-risk individuals.

No MeSH data available.


Related in: MedlinePlus

Receiver operator characteristic (ROC) curve for total scores on the four-item weighted absconsion risk scale (AUC = 0.75).
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pone.0138819.g001: Receiver operator characteristic (ROC) curve for total scores on the four-item weighted absconsion risk scale (AUC = 0.75).

Mentions: ROC analysis was performed on the total scores of the weighted scale to examine the predictive accuracy of the final risk assessment scale and identify a suitable cut-off score. These analyses (Fig 1) yielded an AUC statistic of 0.75 (95% CI = 0.63 to 0.87) and determined that a cut-off score of one (i.e., ≤ zero = low-risk; ≥ one = high-risk) represented the best trade-off between sensitivity and specificity. Applying this cut-off, 36% and 64% of the sample were classified as high- and low-risk, respectively. The proportion of absconders correctly classified as high-risk (sensitivity) and the proportion of non-absconders classified as low-risk (specificity) was 0.67 (95% CI = 0.45 to 0.84) and 0.71 (95% CI = 0.62 to 0.79). The probability that a patient classified as high-risk would go on to abscond was low (PPV = 0.34; 95% CI = 0.21 to 0.49), however, the likelihood that a low-risk patient would not abscond was high (NPV = 0.91; 95% CI = 0.82 to 0.96). Finally, the diagnostic OR indicated that the odds of being classified as high-risk were approximately five times higher among absconders relative to non-absconders (OR = 4.97; 95% CI = 1.93 to 12.79).


A Prospective Cohort Study of Absconsion Incidents in Forensic Psychiatric Settings: Can We Identify Those at High-Risk?

Cullen AE, Jewell A, Tully J, Coghlan S, Dean K, Fahy T - PLoS ONE (2015)

Receiver operator characteristic (ROC) curve for total scores on the four-item weighted absconsion risk scale (AUC = 0.75).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581860&req=5

pone.0138819.g001: Receiver operator characteristic (ROC) curve for total scores on the four-item weighted absconsion risk scale (AUC = 0.75).
Mentions: ROC analysis was performed on the total scores of the weighted scale to examine the predictive accuracy of the final risk assessment scale and identify a suitable cut-off score. These analyses (Fig 1) yielded an AUC statistic of 0.75 (95% CI = 0.63 to 0.87) and determined that a cut-off score of one (i.e., ≤ zero = low-risk; ≥ one = high-risk) represented the best trade-off between sensitivity and specificity. Applying this cut-off, 36% and 64% of the sample were classified as high- and low-risk, respectively. The proportion of absconders correctly classified as high-risk (sensitivity) and the proportion of non-absconders classified as low-risk (specificity) was 0.67 (95% CI = 0.45 to 0.84) and 0.71 (95% CI = 0.62 to 0.79). The probability that a patient classified as high-risk would go on to abscond was low (PPV = 0.34; 95% CI = 0.21 to 0.49), however, the likelihood that a low-risk patient would not abscond was high (NPV = 0.91; 95% CI = 0.82 to 0.96). Finally, the diagnostic OR indicated that the odds of being classified as high-risk were approximately five times higher among absconders relative to non-absconders (OR = 4.97; 95% CI = 1.93 to 12.79).

Bottom Line: In multivariate analyses, four factors relating to offending and behaviour emerged as the strongest predictors of absconsion: history of sexual offending, previous absconsion, recent inpatient verbal aggression, and recent inpatient substance use.The weighted risk scale derived from these factors had moderate-to-good predictive accuracy (ROC area under the curve: 0.80; sensitivity: 067; specificity: 0.71), a high negative predictive value (0.91), but a low positive predictive value (0.34).Potentially-targetable recent behaviours, such as inpatient verbal aggression and substance use, are strong predictors of absconsion in forensic settings; the absence of these factors may enable clinical teams to identify unnecessarily restricted low-risk individuals.

View Article: PubMed Central - PubMed

Affiliation: Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.

ABSTRACT

Background: Incidents of absconsion in forensic psychiatric units can have potentially serious consequences, yet surprisingly little is known about the characteristics of patients who abscond from these settings. The few previous studies conducted to date have employed retrospective designs, and no attempt has been made to develop an empirically-derived risk assessment scale. In this prospective study, we aimed to identify predictors of absconsion over a two-year period and investigate the feasibility of developing a brief risk assessment scale.

Methods: The study examined a representative sample of 135 patients treated in forensic medium- and low-secure wards. At baseline, demographic, clinical, treatment-related, and offending/behavioural factors were ascertained from electronic medical records and the treating teams. Incidents of absconsion (i.e., failure to return from leave, incidents of escape, and absconding whilst on escorted leave) were assessed at a two-year follow-up. Logistic regression analyses were used to determine the strongest predictors of absconsion which were then weighted according to their ability to discriminate absconders and non-absconders. The predictive utility of a brief risk assessment scale based on these weighted items was evaluated using receiver operator characteristics (ROC).

Results: During the two-year follow-up period, 27 patients (20%) absconded, accounting for 56 separate incidents. In multivariate analyses, four factors relating to offending and behaviour emerged as the strongest predictors of absconsion: history of sexual offending, previous absconsion, recent inpatient verbal aggression, and recent inpatient substance use. The weighted risk scale derived from these factors had moderate-to-good predictive accuracy (ROC area under the curve: 0.80; sensitivity: 067; specificity: 0.71), a high negative predictive value (0.91), but a low positive predictive value (0.34).

Conclusion: Potentially-targetable recent behaviours, such as inpatient verbal aggression and substance use, are strong predictors of absconsion in forensic settings; the absence of these factors may enable clinical teams to identify unnecessarily restricted low-risk individuals.

No MeSH data available.


Related in: MedlinePlus