Behavioural
Study Design: SUPPORT is a multi-centre, open-label, randomised controlled trial evaluating the effectiveness of a structured aftercare intervention for people completing community treatment for alcohol or drug dependence. Hypothesis: The primary hypothesis is that participants receiving the Recovery Check-In (RCI) intervention will have better recovery outcomes than those receiving treatment as usual (TAU) over 12 months. This hypothesis was chosen based on evidence from studies conducted in the United States showing that structured aftercare support can improve outcomes following substance use treatment, but where robust UK evidence is currently lacking. Setting: The study will be conducted in NHS and third-sector community substance use disorder (SUD) treatment services across England. Participants: The study aims to recruit approximately 1,938 participants across around 20 treatment services in England. Adults who are completing an episode of community treatment for moderate to severe alcohol or drug dependence will be eligible to take part. Clinical teams at participating services will identify potentially eligible individuals before discharge from treatment and provide information about the study. People who choose to take part will give written informed consent. There are a few exclusion criteria, meaning the study is open to a wide range of people leaving treatment. This approach was informed by patient and public contributors, who emphasised the importance of keeping eligibility broad and inclusive. Allocation to study groups: Participants will be randomly allocated, with an equal chance, to one of two groups: Recovery Check-In (RCI) Treatment as usual (TAU) Randomisation will be carried out centrally, and allocation will not be known to researchers at the time of baseline assessment. Randomisation will be stratified by site and by primary substance use disorder category (alcohol, cannabis, cocaine, opioids, or other) to maintain balance across key participant characteristics. Block sizes will be varied and concealed within the system. The allocation mechanism is automated, independent, and free from researcher influence, and allows a fair comparison between groups and reflects current routine care in the UK. Recovery Check-In (RCI): Participants allocated to the RCI group will receive structured aftercare support over 12 months. This includes one initial face-to-face (or online) meeting shortly after treatment discharge, followed by brief check-in contacts by phone or video call. These will take place weekly during the first two months, fortnightly during months three to six, and monthly during months seven to twelve. The intervention focuses on practical support, personal goals, and coping strategies. RCI will be delivered by trained peer workers, drug workers, and psychology assistants. Treatment as usual (TAU): Participants allocated to the comparison group will receive the standard discharge and follow-up support routinely provided by their treatment service. This reflects current practice and allows the additional benefit of Recovery Check-In to be assessed. Data collection: All study data will be recorded using secure electronic case report forms. After discharge from treatment, a researcher will contact participants to arrange a baseline research appointment. At the start of this appointment, final eligibility criteria will be confirmed prior to randomisation. Baseline assessments will then be completed. All assessments can be completed by phone or video call, depending on participant preference. Participants may withdraw from the study at any time without affecting their care. Follow-up and additional data: Participants will be followed up at regular intervals over 12 months. With consent, data will also be linked to national treatment records to confirm treatment re-admission. A small number of participants will be invited to take part in qualitative interviews during the pilot phase and at the end of the study to explore experiences of the intervention. The study includes an initial pilot phase to ensure procedures are acceptable and workable before continuing to the full trial. To minimise potential researcher effects and bias, outcome data will be collected using standardised, validated measures wherever possible. Researchers conducting follow-up assessments will receive training and will follow detailed study procedures. Randomisation will be carried out centrally, and allocation will not be known to researchers at the time of baseline assessment. Analysis will be conducted according to a pre-specified analysis plan.