Table 2 Trial measures

Eligibility measures

 Pre-eligibility questions

Brief information on prior barriers to seeking AOD treatment and current substance use problem severity collected using structured questions.

 Demographic information

Demographic information (e.g. age, gender, education level) collected using structured questions.

 SCID-5-RV

Presence and severity of MA use disorder assessed using the Structured Clinical Interview for DSM-5 Research Version (SCID-5-RV) [28] in combination with clinical review. Scores range 0–11, with higher scores suggesting greater severity of MA use disorder. Scores ≤1 or ≥ 6 typically warrant clinical review for inclusion in the study. The SCID-5-RV will also be used as a measure of change in this trial.

 CAPE-15

Psychotic-like experiences assessed using the Community Assessment of Psychotic-like Experiences, 15-item revision (CAPE-15) [32]. Score range 1–4 for frequency and 1–4 for distress, with higher scores indicating greater symptom frequency and distress. Scores >1.47 (cut-off value for people at ultra-high risk of psychosis [33]) will be reviewed in conjunction with information on recent psychiatric- or AOD-related hospitalisations and current medications. The CAPE-15 will also be used as a measure of change in this trial.

 SIDAS

Suicidal risk assessed with the Suicidal Ideation Attributes Scale (SIDAS) [34]. Scores >21 indicate a high risk of suicidal behaviour. Further structured clinical questions will be asked when required to assess risk.

 Other eligibility

Structured questions assess additional inclusion/exclusion criteria (e.g. current AOD treatment, diagnosed primary psychotic disorder).

Primary outcome

 DUDIT

MA problem severity assessed with the Drug Use Disorders Identification Test (DUDIT) [35] at 3 months post-randomisation. Scores range 0–44. Higher score suggests more severe MA use problem. The DUDIT will also be used as a secondary outcome measure (6 and 12 months post-randomisation). The time frame has been adapted to cover month prior to assessment (rather than year), so that planned follow-up assessments can be performed.

Secondary outcomes

 TLFB

Days of MA use, amount of MA used and days of other drug use in past 28 days assessed with the Timeline Follow-back (TLFB) calendar-based assessment tool [36].

 CEQ

Past-week frequency of MA cravings, and strength of strongest craving, assessed with the Craving Experience Questionnaire (CEQ) [37]. Scores range from 0 to 100. Higher score indicates greater craving frequency and strength.

 DASS-21

Past-month psychological functioning assessed with the Depression, Anxiety and Stress Scale-21 (DASS-21) [38]. Total scores range from 0 to 63 (depression scored 0–21, anxiety scored 0–21, stress scored 0–21). Higher score indicates higher symptom severity.

 EUROHIS-QOL single item

Past-month quality of life (QoL) assessed with the EUROHIS-QOL single item [39].

 AEs

Adverse events monitored with structured questions relevant to MA use disorder cohort and trials of psychotherapeutic interventions.

Cost-effectiveness

 EQ-5D-5L+

Quality-adjusted life years (QALYs) assessed with the EuroQol, 5 dimensions, 5 levels (EQ-5D-5L+) [40, 41].

 3Mg trial’s Health-care Resource Use Questionnaire

Health resource usage in past 3 months assessed with the 3Mg trial’s Health-care Resource Use Questionnaire [42].

 WHO HPQ28-Day

Time lost from work or from lower work productivity assessed with the WHO Health and Work Performance Questionnaire Clinical Trials 28-Day Version (WHO HPQ28-Day) [43].

Additional measures

 SBQ

Barriers to help-seeking for MA use disorder assessed with the Short Barriers Questionnaire (SBQ) [44]. Scores range from 0 to 66 (low perceived need scored 0–27; stigma scored 0–18; apprehension scored 0–21). Higher scores indicate greater importance of barrier.

 RR-ICR

Readiness to change at randomisation assessed with the Readiness Ruler I-C-R (RR-ICR) [45]. Importance, confidence and readiness scored 0–10. Higher scores indicate greater change readiness. The RR-ICR will be used as a predictor of treatment response in this trial.

 CIS

Impulse control assessed with the Cognitive Impulsivity Suite (CIS) [46] in a subsample of participants willing to complete the additional task.

 Sleep measures

Chronotype assessed with the Reduced Morningness-Eveningness Questionaire (rMEQ) [47, 48], and sleep quality and disturbances assessed with the Pittsburgh Sleep Quality Index (PSQI) [49].

 Mixed-methods program evaluation

Program reach assessed by response rate to trial advertising, participant engagement (i.e. number of sessions completed), reach to rural and regional areas and health inequity groups (i.e. participation rates by gender, Aboriginal and Torres Strait Islander status, lesbian, gay, bisexual, transgender, intersex, queer, and other LGBTIQ+ status, and culturally and linguistically diverse background, disability status). R2C-M program feedback via participant qualitative interviews and the Working Alliance Inventory – Short Revised (WAI-SR) [50] with ~30% of participants allocated to the intervention condition.