Hospital-treated self-harm is common and costly, and is associated with repeated self-harm and suicide.

To investigate the effectiveness of a brief contact intervention delivered via short message service (SMS) text messages in reducing hospital-treated self-harm re-presentations in three hospitals in Sydney (2017–2019), Australia. Trial registration number: ACTRN12617000607370.

A randomised controlled trial with parallel arms allocated 804 participants presenting with self-harm, stratified by previous self-harm, to a control condition of treatment as usual (TAU) (n = 431) or an intervention condition of nine automated SMS contacts (plus TAU) (n = 373), over 12 months following the index self-harm episode. The primary outcomes were (a) repeat self-harm event rate (number of self-harm events per person per year) at 6-, 12- and 24-month follow-up and (b) the time to first repeat at 24-month follow-up.

The event rate for self-harm repetition was lower for the SMS compared with TAU group at 6 months (IRR = 0.79, 95% CI 0.61–1.01), 12 months (IRR = 0.78, 95% CI 0.64–0.95) and 24 months (IRR = 0.78, 95% CI 0.66–0.91). There was no difference between the SMS and TAU groups in the time to first repeat self-harm event over 24 months (HR = 0.96, 95% CI 0.72–1.26). There were four suicides in the TAU group and none in the SMS group.

The 22% reduction in repetition of hospital-treated self-harm was clinically meaningful. SMS text messages are an inexpensive, scalable and universal intervention that can be used in hospital-treated self-harm populations but further work is needed to establish efficacy and cost-effectiveness across settings.

医院治疗的自残行为很常见，而且费用昂贵，并且与反复的自残和自杀有关。

旨在调查澳大利亚悉尼三家医院（2017-2019 年）通过短信服务 (SMS) 短信提供的简短接触干预在减少医院治疗的自残再呈现方面的有效性。试用注册号：ACTRN12617000607370。

一项平行组随机对照试验将 804 名表现出自残行为的参与者按既往自残情况分层，分配至照常治疗控制条件 (TAU) ( n = 431) 或 9 个自动 SMS 联系人的干预条件（加上TAU) ( n = 373)，自残事件发生后 12 个月以上。主要结局是 (a) 6、12 和 24 个月随访时的重复自残事件率（每人每年自残事件的数量），以及 (b) 24 个月时首次重复的时间。月随访。

与 TAU 组相比，SMS 组在 6 个月（IRR = 0.79，95% CI 0.61–1.01）、12 个月（IRR = 0.78，95% CI 0.64–0.95）和 24 个月时重复自残的事件率较低（IRR = 0.78，95% CI 0.66–0.91）。SMS 组和 TAU 组在 24 个月内首次重复自残事件的时间上没有差异（HR = 0.96，95% CI 0.72-1.26）。TAU 组中有 4 人自杀，而 SMS 组没有人自杀。

医院治疗的自残重复率减少了 22%，具有临床意义。短信是一种廉价、可扩展且普遍的干预措施，可用于医院治疗的自残人群，但需要进一步开展工作来确定跨环境的有效性和成本效益。