Liaison and Diversion (L&D) has twin objectives: improving mental health outcomes and reducing re‐offending. Early diversion from police custody seems promising, but evidence of benefit is required to sustain such programmes. To test the hypothesis that contact with L&D services while in police custody would lead to improved mental health outcomes and a reduction in type and level of offending, we used a pre–post service use design. National Health Service (NHS) records in two counties were searched for evidence that patients had been involved with L&D services while in police custody during the period July 2009–December 2017. We defined January 2009–July 2014 as the pre‐intervention period and any time after contact as the post‐intervention period. Data from the Police National Computer were gathered for each period for these individuals, to assess their pre‐post L&D contact offending histories. NHS Trust data were similarly gathered to assess their pre‐post use of mental health legislation. 4,462 individuals were identified who had used L&D services in police custody. There were statistically significant reductions in the amount of offending following contact with the L&D service (whether one or two contacts), regardless of offence type. Statistically significant reductions were also observed in use of the four most commonly used legislative powers for detaining patients in hospital on mental disorder grounds, regardless of offending status (prolific/non‐prolific). Our results indicate positive associations between the L&D interventions and change in offending and use of compulsory hospital detention. Whilst our research does not allow a direct causal relationship to be established in either area, the findings go beyond other impact assessments of L&D which have either been with small samples or relied only on qualitative data or expert opinion.

中文翻译：

---

警务中的联络和转移干预措施是否能产生计划的影响：在两个警察中进行纵向评估？

联络与转移（L＆D）有两个目标：改善心理健康结果并减少再犯罪。尽早撤离警察拘留所似乎是有希望的，但是维持这种方案需要受益的证据。为了检验这一假设，即在警察羁押期间与L＆D服务部门联系会改善精神健康状况并减少犯罪类型和程度，我们使用了事前服务使用设计。搜寻了两个县的国家卫生服务（NHS）记录，以寻找证据表明患者在2009年7月至2017年12月期间在警察拘留期间参与了L＆D服务。我们将2009年1月至2014年7月定义为干预前的时期以及任何接触后的时间作为干预后的时间。在每个时期从警察国家计算机收集数据，以评估这些人在事前与事后接触的犯罪历史。同样收集了NHS Trust数据，以评估其对精神卫生立法的事前使用。确定了4,462个人在警察拘留中使用了L＆D服务。与L＆D服务部门联系（无论是一名还是两名联系人）之后，无论违规类型如何，犯罪数量都有统计上的显着减少。在使用四种最常用的立法权力以精神障碍为由将患者拘留在医院时，无论犯罪状态如何（多产/不多产），也观察到统计学上的显着减少。我们的结果表明L＆D干预和改变强制性医院拘留的犯罪和使用方式。尽管我们的研究不允许在这两个领域中建立直接因果关系，但研究结果超出了对L＆D的其他影响评估的范围，这些评估要么只是样本量很小，要么仅依赖定性数据或专家意见。