Table 2 Table of all clinical and research measures included in study

Basic

Demographics

10 Questions: basic demographics including; age, gender, employment, relationship status, education level, living situation and Aboriginal and Torres Strait Islander background.

Research Interview: Week 0 (baseline) day 1

Cannabis Use

Cannabis Use

4 semi-structured questions: exploring frequency, amount and method of cannabis use in the last 4-weeks

Research Interview: Weeks 0, 4, 8, 12, 24

Cannabis Withdrawal Scale (CWS) [35]

19 items on a 10-point Likert Scale, with 0 = Not at all to 10 = Extremely. The CWS is used as a diagnostic instrument in clinical and research settings to assess cannabis withdrawal symptoms. Participants are asked how they feel over the last 24 h in 8 domains; irritability, depression, anxiety, cannabis cravings, physical symptoms, sleep difficulty, restlessness and appetite.

Research Interview and Clinical Reviews: Weekly

Marijuana Craving Questionnaire-short form (MCQ) [66]

12 items on a 7-point Likert scale, with 1 = strongly disagree to 7 = strongly agree. The MCQ is a self-report instrument that assesses marijuana craving along 4 dimensions; compulsivity, emotionality, expectancy and purposefulness.

Research Interview: Weeks 0, 4, 8, 12, 24

Cannabis Problems Questionnaire (Adult revised- CPQ-R) [67]

27 items on a 11-point Likert scale, with 0 = doesn’t apply to me to 10 = strongly apply to me. The CPQ-R measures acute and physical consequences, psychological consequences, and social consequences of cannabis use.

Research Interview: Weeks 0, 4, 8, 12, 24

Self-coping and efficacy for quitting cannabis questionnaire [68]

20 items on a 7-point Likert scale, with 1 = not at all confident to 7 = very confident. Participants are asked to indicated their confidence in their ability to resist the temptation to use cannabis in a variety of interpersonal and intrapersonal situations.

Research Interview: Weeks 0, 4, 8, 12, 24

Modified Time Line Follow Back (adapted) [40]

Using a modified Time Line Follow Back approach examining cannabis use in preceding 4 week period.

Research Interview: Weeks 0, 4, 8, 12, 24

Other Substance Use

Australian Treatment Outcome Profile (ATOP) [36]

3 Part Questionnaire:

Research Interview: Weeks 0, 4, 8, 12, 24

1. Substance use; items refer to substance use over the last 4-weeks, in particular: alcohol, amphetamines, benzodiazepines, heroin, other opioids, cocaine, other substances and tobacco.

2. Injecting risk behaviour; 2-items exploring injecting behaviour in the last 4-weeks.

3.Health and Well-being; 11-items investigating the participants’ accommodation arrangements, psychological and physical health and quality of life.

FagerstrÖm Test for nicotine dependence (FTND) [69]

6 item questionnaire that measures nicotine dependency, with a total available score of 10.

Research Interview: Weeks 0, 4, 8, 12, 24

The Alcohol Use Disorders Identification Test (AUDIT) [70]

10 item questionnaire covering domains of alcohol consumption, drinking behaviour and alcohol related problems. Responses to each question are scored from 0 to 4, giving a maximum possible score of 40.

Research Interview: Weeks 0, 4, 8, 12, 24

Opioid Related Behaviours in Treatment (ORBIT) scale (modified) [71]

8 item questionnaire on a 5-point Likert scale ranging from 0 = never to 4 = very often. The questionnaire explores opioid-related behaviours that are divergent, unexpected, non-adherence to medication, unsanctioned diversion of medication to others, hazardous use or misuse. ORBIT questions modified for cannabis dependent population.

Research Interview: Week 12

Mental Health

Depression, Anxiety and Stress scale (DASS) Short-form [51]

21 item questionnaire on a 4-point Likert scale, ranging from 0 = did not apply to me at all to 3 = applied to me very much or most pf the time. The DASS 21 measures the severity of symptoms of depression, anxiety and stress and enables clinicians to measure a patient’s response to treatment.

Research Interview: Weeks 0, 4, 8, 12, 24

Primary Care Post Traumatic Stress Disorder (PC-PTSD) [72]

4 item questionnaire that explores whether a patient has ever experienced a traumatic event (e.g. a serious accident, physical/sexual assault/abuse, natural or political disaster etc.) over the course of their life. If so, participants answer a series of Yes/No questions.

Research Interview: Weeks 0, 4, 8, 12, 24

Brief Psychiatric Rating Scale (BPRS) [37]

18 item questionnaire on a 7-point Likert scale, ranging from 1 = not present to 7 = extremely severe. Clinicians measure psychiatric symptoms such as depression, anxiety, hallucinations and unusual behaviour.

Research Interview: Weeks 0, 4, 8, 12, 24

Physical Health

Short form 36 health survey questionnaire (SF-36) [50]

36 item questionnaire using a mixed scale. Domains covered in the survey include; physical functioning, role limitations due to physical problems, social functioning, bodily pain, general mental health, role limitations due to emotional problems, vitality and general health problems.

Research Interview: Weeks 0, 4, 8, 12, 24

Brief Pain Inventory - Short form (BPI) [53]

5 items taken from Brief Pain Inventory-Short form using a 10-point Likert scale, ranging from 0-no pain to 10 = worst pain imaginable. Participants are asked to think about any abnormal pain experienced in the last 7 days and rate the intensity and interference of the pain in the participants’ life.

Research Interview: Weeks 0, 4, 8, 12, 24

Athens Insomnia Scale (AIS) [54]

7 item questionnaire using a 4-point Likert scale ranging from 0 = none to 4 = very severe. The AIS is a self-assessment psychometric instrument designed for quantifying sleep difficulty based on the ICD-10 criteria.

Research Interview: Weeks 0, 4, 8, 12, 24

Sheehan Disability Scale (SDS) [73]

3 item instrument using a 10-point Likert scale ranging from 0 = not at all to 10 = very severe. The SDS asks participants to best rate their impairment with work, social life/leisure activities and family life/home responsibilities.

Research Interview: Weeks 0, 4, 8, 12, 24

Visual Analogue Scale of client ratings on medication effects [42]

5 item questionnaire using a scale from 0 to 100 measuring subjective liking and strength of drug effect, comparability to cannabis, sedation, bad effects and subjective physiological effects

Research Interview: Weeks 0, 4, 8, 12, 24

Social/ Other

Opioid Treatment Index- Crime (OTI-Crime) [55]

8 questions modified from the full Opioid Treatment Index. The modified version concentrates on questions relating to criminality and focuses on the frequency of recent criminal behaviour in four areas: property crime, drug dealing, fraud and crimes involving violence.

Research Interview: Weeks 0, 4, 8, 12, 24

Health and Work Performance Questionnaire (HPQ) -Short Form Absenteeism and Presenteeism [74]

4 Questions modified from the Health and Work Performance questionnaire (HPQ). The HPQ is designed to estimate the workplace costs of health problems in terms of reduced job performance, sickness absence, and work-related accidents/injuries.

Research Interview: Weeks 0, 4, 8, 12, 24

National Evaluation of Pharmacotherapies for Opioid Dependence (NEPOD) - Health Service Utilisation (HSU) [75]

5 questions adapted from the NEPOD study. The HSU section of the NEPOD focusses on health services used in the last 4-weeks, frequency of use and cost of service to the participant.

Research Interview: Weeks 0, 4, 8, 12, 24

Testing the Blind

5 questions exploring the participants’ subjective opinion of study drug allocation.

Research Interview: Weeks 4, 8, 12, 24

Patient’s Global Impression of Change Scale (PGICS) [64]

1 question modified from the Global Rating of Change (GLOC) survey exploring the participants’ subjective opinion of change since starting study.

Day: 85

Cognitive Assessment

Wechsler Test of Adult Reading (WTAR) [61]

Verbal pronunciation of 50 words with irregular phoneme-to-grampheme conversion. Total correct recorded

Research Interview: Weeks 0

Eriksen Arrow Flankers (with no-go) [56]

Speed of response to target stimuli flanked with either neutral, congruent or incongruent stimuli (24 each). Random 10% (n = 8) trials require with-holding of response (no-go). Reaction time; errors and false alarms recorded

Research Interview: Weeks 0, 4, 24

1,2,3-Back Task [58]

Identification of repetition in a rapid sequence of stimuli, either 1, 2, or 3 stimuli prior (30, 75, 75 stimuli respectively; 25% targets). Reaction time, accuracy, false-positives recorded

Research Interview: Weeks 0, 4, 24

Symbol-Digit Substitution Task (SDMT) [59]

Decoding symbols related to presented digit; 87 trials; Reaction Time and Accuracy recorded

Research Interview: Weeks 0, 4, 24

Stop-Signal Task (SST) [57]

Withholding of already initiated motor response after a delay; 12 target trials of 48; reaction time, errors, stop signal response time recorded

Research Interview: Weeks 0, 4, 24

Rapid Visual Information Processing (RVIP) [60]

Response to high working memory load (3 back) stimuli; 24 targets in 300 stimuli; reaction time; accuracy and false positive responses recorded

Research Interview: Weeks 0, 4, 24

Rey Auditory Verbal Learning Task [62]

Retention of a 15 item word list presented on 5 occasions. Number of words recalled on each presentation, following presentation of a novel list of 15 words; and then after brief and long delays recorded. Recognition of target stimuli also assessed.

Research Interview: Weeks 0, 4, 24