Cannabis Use DisorderPhase 2GRACENCT05957848
Guanfacine Extended-release for Adolescents With Cannabis Use
A Phase 2 study testing Guanfacine Extended Release Oral Tablet, Residential withdrawal and Engagement with alcohol and other drug services in people with Cannabis Use Disorder, run by Orygen at 1 site in Australia.
Trial summary
A randomized controlled trial to assess the efficacy of extended-release guanfacine to reduce cannabis use frequency in young people with cannabis use disorder following a period of monitored abstinence. Read more about this study
- Who is it for?
- Ages 12 to 25 years
- Conditions the study is for
- Cannabis Use Disorder
- What is being tested?
- Guanfacine Extended Release Oral Tablet, Residential withdrawal and Engagement with alcohol and other drug services
- Type of treatment
- Pill or oral medicine, Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- 1 siteAustralia
- Study dates
- 27 Jul 2023to 30 Jun 2026
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 25 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- 12-25 years of age (inclusive) at consent;
- Seeking treatment for cannabis use;
- DSM-5 Cannabis Use Disorder, mild, moderate or severe;
- Self-reported cannabis use on average at least 5 days/week during the 28 days prior to screening with a THC positive urine drug screen on the day of screening; and
- Able to provide informed consent (both adequate IQ and English fluency; <18-year-olds will provide consent themselves in addition to parent/guardian consent).
Who cannot join
- DSM-5 substance use disorder (moderate or severe) except cannabis or nicotine;
- Any unstable medical, psychiatric or neurological condition or medical contraindicating study participation;
- Diagnosis of a psychotic or bipolar illness;
- Acute suicidality as assessed by clinician;
- Prescribed antipsychotics, benzodiazepines or other sedative medications, or other medications for the treatment of ADHD. If prescribed antidepressants, the participant must have been on a stable dose for more than 2 weeks at screening;
- A history of heart disease or cardiac risk factors (e.g. arrhythmias);
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- Abnormal liver or thyroid function as indicated by clinically-significant findings on blood tests;
- Pregnancy, breast feeding or, if sexually active and able to become pregnant, no effective contraception.
- Intention to enter residential rehabilitation after treatment in the YSAS residential withdrawal facility.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Emily A Karanges, PhD contact
Australia1 site, 1 recruiting
- Recruiting
Orygen
Parkville, Victoria, 3052
Gillinder Bedi, DPsych, +61 3 9966 9100, gill.bedi@orygen.org.au
Holly I Bowman, BPsySc(Hons), +61 3 9966 9100, holly.bowman@orygen.org.au
About this study
Official title: Guanfacine Extended-release Randomised Controlled Trial for Adolescents With Cannabis usE (GRACE)
A randomized controlled trial to assess the efficacy of extended-release guanfacine to reduce cannabis use frequency in young people with cannabis use disorder following a period of monitored abstinence.
- Conditions
- Cannabis Use Disorder
- Being tested
- Guanfacine Extended Release Oral Tablet, Residential withdrawal, Engagement with alcohol and other drug services, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Guanfacine Extended Release Oral TabletDrug
Also called Intuniv, Guanfacine XR
Target dose 4 mg daily
Residential withdrawalBehavioural
4-14 days in residential withdrawal treatment
Engagement with alcohol and other drug servicesBehavioural
Ongoing engagement with a youth drug and alcohol service for counselling or other support for the duration of the study
PlaceboDrug
Placebo capsule taken daily
| Study group | Role | What they receive |
|---|---|---|
| Guanfacine extended-release | Experimental | Guanfacine extended-release (target dose 4 mg), once daily for approximately 12 weeks plus treatment as usual Receives: Drug: Guanfacine Extended Release Oral Tablet; Behavioral: Residential withdrawal; Behavioral: Engagement with alcohol and other drug services |
| Placebo | Placebo comparator | Placebo once daily for approximately 12 weeks plus treatment as usual Receives: Behavioral: Residential withdrawal; Behavioral: Engagement with alcohol and other drug services; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Efficacy - change from baseline in cannabis use frequency following monitored abstinence
Change from baseline in average frequency of cannabis use (days of use/week) in the 4 weeks immediately following discharge from residential withdrawal, assessed weekly using the Timeline Follow-Back.
Measured: Baseline and weekly in the 4 week outpatient phase immediately following discharge from residential withdrawal
Secondary outcomes (13)
Change from baseline in cannabis use frequency following monitored abstinence (categorical)
Change from baseline in average frequency of cannabis use in the 4 weeks immediately following discharge from residential withdrawal, assessed weekly using the Timeline Follow-Back and categorized as follows: heavy use (5-7 days per week), moderate use (3-5 days) or light use (0-1 days)
Measured: Baseline and weekly in the 4 weeks immediately following discharge from residential withdrawal
Cannabis exposure
The number of urine toxicology tests that are positive for cannabis exposure
Measured: Approximately weekly between Baseline (week 0) and the end of treatment visit (week C7), approximately 12 weeks from baseline
Change from baseline in cannabis use disorder symptoms
Change from baseline in number of cannabis use disorder symptoms endorsed at end of treatment as indexed by the Structured Clinical Interview for DSM-5 (SCID-5)
Measured: Baseline and end of Maintenance phase (4 weeks post discharge from residential withdrawal)
Cannabis withdrawal symptoms during residential withdrawal admission
Measured with the Cannabis Withdrawal Scale
Measured: Daily during residential treatment for 4 to 14 days
Sleep quality (subjective) during residential withdrawal admission
Measured with the PROMIS Sleep Disturbance Scale
Measured: Daily during residential treatment for 4 to 14 days
Cannabis craving during residential withdrawal admission
Measured with the Brief Substance Craving Scale - Cannabis
Measured: Daily during residential treatment for 4 to 14 days
Sleep quality (objective) during residential withdrawal admission
Measured with wrist actigraphy
Measured: Daily during residential treatment for 4 to 14 days
Food intake during residential withdrawal admission
Measured with a food intake dairy
Measured: Daily during residential treatment for 4 to 14 days
Treatment engagement (residential)
Measured as the longest consecutive length of stay in residential withdrawal (4-14 days)
Measured: Baseline to end of treatment
Treatment engagement (outpatient)
Measured as the number of outpatient alcohol and other drug counselling sessions completed
Measured: Baseline to end of treatment
Change from baseline in daily functioning - social and occupational
Measured with the Social and Occupational Functioning Assessment scale (SOFAS)
Measured: Baseline and end of maintenance period assessments (4 weeks post discharge from residential withdrawal)
Change from baseline in daily functioning - multidimensional
Measured with the Multidimensional Adolescent Functioning Scale (MAFS)
Measured: Baseline and end of maintenance period assessments (4 weeks post discharge from residential withdrawal)
Change from baseline in daily functioning - social inclusion
Measured with the Filia Social Inclusion Measure - 16 item scale (FSIM-16).
Measured: Baseline and end of maintenance period assessments (4 weeks post discharge from residential withdrawal)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Jul 2023
- Study start27 Jul 2023
- Primary completion31 Dec 2025 (estimated)
- Study completion30 Jun 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cannabis Use DisorderStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Orygen
- Sponsor type
- University, hospital or other
- Collaborators
- Youth Support and Advocacy Service, University of Melbourne
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05957848
- Sponsor's protocol ID
- 22389
- Acronym
- GRACE
- Status last verified
- Jul 2025
- First submitted
- 15 Jun 2023
- Last updated
- 31 Jul 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 31 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Guanfacine Extended-release Randomised Controlled Trial for Adolescents With Cannabis usE (GRACE)
- ClinicalTrials.gov ID
- NCT05957848
- Acronym / sponsor ID
- GRACE / 22389
- Conditions
- Cannabis Use Disorder
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- OrygenUniversity, hospital or other
- Collaborators
- Youth Support and Advocacy Service, University of Melbourne
- Study start
- 27 Jul 2023 (actual)
- Primary completion
- 31 Dec 2025 (estimated)
- Study completion
- 30 Jun 2026 (estimated)
- First posted
- 24 Jul 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A randomized controlled trial to assess the efficacy of extended-release guanfacine to reduce cannabis use frequency in young people with cannabis use disorder following a period of monitored abstinence.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Guanfacine extended-release | Experimental | Drug: Guanfacine Extended Release Oral Tablet, Behavioral: Residential withdrawal, Behavioral: Engagement with alcohol and other drug servicesGuanfacine extended-release (target dose 4 mg), once daily for approximately 12 weeks plus treatment as usual |
| Placebo | Placebo comparator | Behavioral: Residential withdrawal, Behavioral: Engagement with alcohol and other drug services, Drug: PlaceboPlacebo once daily for approximately 12 weeks plus treatment as usual |
Who may qualify
- Ages
- 12 to 25 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (5 listed)
- 12-25 years of age (inclusive) at consent;
- Seeking treatment for cannabis use;
- DSM-5 Cannabis Use Disorder, mild, moderate or severe;
- Self-reported cannabis use on average at least 5 days/week during the 28 days prior to screening with a THC positive urine drug screen on the day of screening; and
- Able to provide informed consent (both adequate IQ and English fluency; <18-year-olds will provide consent themselves in addition to parent/guardian consent).
Key exclusion criteria (9 listed)
- DSM-5 substance use disorder (moderate or severe) except cannabis or nicotine;
- Any unstable medical, psychiatric or neurological condition or medical contraindicating study participation;
- Diagnosis of a psychotic or bipolar illness;
- Acute suicidality as assessed by clinician;
- Prescribed antipsychotics, benzodiazepines or other sedative medications, or other medications for the treatment of ADHD. If prescribed antidepressants, the participant must have been on a stable dose for more than 2 weeks at screening;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Guanfacine Extended Release Oral TabletAlso: Intuniv, Guanfacine XRTarget dose 4 mg daily | Drug | Guanfacine extended-release |
| Residential withdrawal4-14 days in residential withdrawal treatment | Behavioural | Guanfacine extended-release, Placebo |
| Engagement with alcohol and other drug servicesOngoing engagement with a youth drug and alcohol service for counselling or other support for the duration of the study | Behavioural | Guanfacine extended-release, Placebo |
| PlaceboPlacebo capsule taken daily | Drug | Placebo |
Primary outcome
Efficacy - change from baseline in cannabis use frequency following monitored abstinence
Time frame: Baseline and weekly in the 4 week outpatient phase immediately following discharge from residential withdrawal
Change from baseline in average frequency of cannabis use (days of use/week) in the 4 weeks immediately following discharge from residential withdrawal, assessed weekly using the Timeline Follow-Back.
13 secondary outcomes
Change from baseline in cannabis use frequency following monitored abstinence (categorical)
Time frame: Baseline and weekly in the 4 weeks immediately following discharge from residential withdrawal
Cannabis exposure
Time frame: Approximately weekly between Baseline (week 0) and the end of treatment visit (week C7), approximately 12 weeks from baseline
Change from baseline in cannabis use disorder symptoms
Time frame: Baseline and end of Maintenance phase (4 weeks post discharge from residential withdrawal)
Cannabis withdrawal symptoms during residential withdrawal admission
Time frame: Daily during residential treatment for 4 to 14 days
Sleep quality (subjective) during residential withdrawal admission
Time frame: Daily during residential treatment for 4 to 14 days
Cannabis craving during residential withdrawal admission
Time frame: Daily during residential treatment for 4 to 14 days
Sleep quality (objective) during residential withdrawal admission
Time frame: Daily during residential treatment for 4 to 14 days
Food intake during residential withdrawal admission
Time frame: Daily during residential treatment for 4 to 14 days
Treatment engagement (residential)
Time frame: Baseline to end of treatment
Treatment engagement (outpatient)
Time frame: Baseline to end of treatment
Change from baseline in daily functioning - social and occupational
Time frame: Baseline and end of maintenance period assessments (4 weeks post discharge from residential withdrawal)
Change from baseline in daily functioning - multidimensional
Time frame: Baseline and end of maintenance period assessments (4 weeks post discharge from residential withdrawal)
Change from baseline in daily functioning - social inclusion
Time frame: Baseline and end of maintenance period assessments (4 weeks post discharge from residential withdrawal)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Jul 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Emily A Karanges, PhD contact
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Guanfacine Extended Release Oral Tablet, Residential withdrawal and Engagement with alcohol and other drug services in people with Cannabis Use Disorder, run by Orygen at 1 site in Australia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 31 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Australia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Gillinder Bedi, DPsych (+61 3 9966 9100, gill.bedi@orygen.org.au), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Efficacy - change from baseline in cannabis use frequency following monitored abstinence (time frame: Baseline and weekly in the 4 week outpatient phase immediately following discharge from residential withdrawal). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Jul 2025; AzTrials last refreshed its copy on 6 Nov 2026.