Using guanfacine to help adolescents reduce cannabis use

Guanfacine Extended-release Randomised Controlled Trial for Adolescents With Cannabis usE (GRACE)

Phase 2 Interventional Orygen · NCT05957848

This study is testing if a medication called guanfacine can help young people aged 12 to 25 cut down on their cannabis use.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment100 (estimated)
Ages12 Years to 25 Years
SexAll
SponsorOrygen Academic / other
Locations1 site (Parkville, Victoria)
Trial IDNCT05957848 on ClinicalTrials.gov

What this trial studies

This clinical trial is a randomized controlled trial designed to evaluate the effectiveness of extended-release guanfacine in decreasing the frequency of cannabis use among adolescents and young adults diagnosed with cannabis use disorder. Participants aged 12 to 25 will undergo a period of monitored abstinence before receiving either guanfacine or a placebo. The study aims to assess changes in cannabis use frequency following treatment. The trial will also involve engagement with alcohol and other drug services to support participants during the intervention.

Who should consider this trial

Good fit: Ideal candidates for this study are adolescents and young adults aged 12 to 25 who are seeking treatment for cannabis use and meet the criteria for cannabis use disorder.

Not a fit: Patients with severe substance use disorders other than cannabis or those with unstable medical or psychiatric conditions may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for adolescents struggling with cannabis use disorder.

How similar studies have performed: While this approach is relatively novel, previous studies have explored pharmacological interventions for substance use disorders, indicating potential for success.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. 12-25 years of age (inclusive) at consent;
2. Seeking treatment for cannabis use;
3. DSM-5 Cannabis Use Disorder, mild, moderate or severe;
4. 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
5. Able to provide informed consent (both adequate IQ and English fluency; \<18-year-olds will provide consent themselves in addition to parent/guardian consent).

Exclusion Criteria:

1. DSM-5 substance use disorder (moderate or severe) except cannabis or nicotine;
2. Any unstable medical, psychiatric or neurological condition or medical contraindicating study participation;
3. Diagnosis of a psychotic or bipolar illness;
4. Acute suicidality as assessed by clinician;
5. 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;
6. A history of heart disease or cardiac risk factors (e.g. arrhythmias);
7. Abnormal liver or thyroid function as indicated by clinically-significant findings on blood tests;
8. Pregnancy, breast feeding or, if sexually active and able to become pregnant, no effective contraception.
9. Intention to enter residential rehabilitation after treatment in the YSAS residential withdrawal facility.

Where this trial is running

Parkville, Victoria

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Cannabis Use Disorder
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.