Practical difficulties in starting active recruitment.

The study tests a structured referral process for opioid overdose survivors, from pre-hospital emergency care to long-term treatment of the individual's substance use-related disorder.

Randomized controlled trial. Subjects are included if they are being treated by an ambulance in the Malmö uptake are for an opioid overdose requiring naloxone antidote administration, and if they sign informed written consent to the study. Subjects are randomized by ambulance staff to either an active intervention, or a control condition:

Intervention: A telephone alert signal is sent from ambulance staff after successful naloxone reversal of an opioid overdose, leading to an active outreach effort from the staff of the addiction research facility, where staff locate the individual and offer her/him formal inclusion in the study.

Control: No telephone alert signal is sent, and the active outreach procedure is not carried out. Ambulance staff hand over written information to the individual about how she/he can apply actively for treatment.

Primary outcome is entry into formal assessment and treatment of the substance use disorder.

Inclusion Criteria:

• survivor of opioid overdose requiring antidote naloxone administration by ambulance staff, and provision of written informed consent

Exclusion Criteria:

• patients unable to understand study information and to provide informed consent