Neural and Psychiatric Consequences of Cannabis Use in Adolescents (Cann-Teen)

April 20, 2026 updated by: Vilma Gabbay, University of Miami
The goal of this study is to investigate the effects of cannabis on brain function among adolescents with depression.

Study Overview

Status

Recruiting

Study Type

Interventional

Enrollment (Estimated)

280

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Vilma Gabbay, MD, JD, MS
  • Phone Number: 305-243-5510
  • Email: vxg595@miami.edu

Study Locations

    • Florida
      • Miami, Florida, United States, 33136
        • Recruiting
        • University of Miami Clinical Research Building
        • Contact:
        • Contact:
        • Principal Investigator:
          • Vilma Gabbay, MD, JD, MS
        • Sub-Investigator:
          • Benjamin Ely, PhD
    • New York
      • Orangeburg, New York, United States, 10962
        • Not yet recruiting
        • Nathan Kline Institute
        • Contact:
        • Principal Investigator:
          • Russell Tobe, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion criteria at baseline.

  • Cannabis users: To capture a wide range of cannabis use frequency, meeting DSM-5 criteria for cannabis use disorder will not be required. However, in order to ensure sufficient exposure, we will require majority of adolescents with cannabis use to have a significant cannabis use (self-reported use on more or equal to 10 of the prior 30 days and positive THC urine toxicology).
  • Depression: Similarly, to capture a wide range of depression illness severity, we will allow participants with subthreshold depression, defined as a raw severity score of >=30 on the Children's Depression Rating Scale-Revised (CDRS-R, for ages 14-17) and as a raw severity score of >=12 on the Montgomery Asberg Depression Rating Scale (MADRS, for ages 18-20). However, we plan for at least 50% of participants with depressive symptoms to have a raw severity score of >=40 on the CDRS-R and of >=20 MADRS, which are considered reliable for depression. Additionally, we will allow participants with a research diagnosis of Major Depressive Disorder as defined by the MINI, even with a CDRS-R score below 30 or a MADRS score below 12. Moreover, because there could be individuals without MDD who have current depressive symptoms, individuals who lack a diagnosis of a depressive disorder but have a CDRS-R score of 30 (or higher) or a MADRS score of 12 (or higher) will be allowed. Through careful recruitment, we will ensure distributions of depression severity. Based on our prior studies employing similar criteria, we anticipate that anhedonia, anxiety and depression severity scores will be normally distributed in our samples.

Exclusion criteria.

All participants:

  • Psychotropic medication free for more than 1 month (or more than three months for medications with a long half-life such as fluoxetine) prior to study enrollment. We have successfully enrolled hundreds of psychotropic medication-free depressed adolescents and young adults to date. Psychotherapy will be allowed.
  • MRI contraindications such as claustrophobia, metallic ink tattoos, orthodontic braces, or pacemakers
  • Positive pregnancy tests
  • Neurological illnesses and medical conditions such as unique pain syndromes (e.g. multiple sclerosis, rheumatoid arthritis)
  • Estimated full-scale IQ <=80 to ensure that participants have the ability to understand the study
  • Current SUD other than cannabis or nicotine. Excluding nicotine use will limit generalization of our findings and impact feasibility. Similarly, alcohol use will be allowed as long as it is not hazardous and does not meet criteria of a DSM-5 disorder (AUDIT-C >5). Therefore, nicotine and alcohol use will be allowed and controlled for. Alcohol and cannabis use (assessed based on breathalyzer from alcohol and self-report for cannabis/THC) on the day of the scan will result in rescheduling the scan as it can affect MRI data.
  • Certified for or self-reported medical cannabis use, or intent to become certified, current stimulant use (methamphetamine or cocaine) by self-report or urine toxicology. Adderall and Vyvanse for ADHD will be allowed as long as use is temporarily paused medication usage at least 3 days before neuroimaging visit. If medication is not discontinued on scan day, scanning at that time will be up to PI discretion.
  • Oral contraceptives will be allowed and controlled for in order to maximize recruitment of older adolescents.

Depressed THC non-users:

  • DSM-5 diagnoses of bipolar disorder, psychotic disorders, autism spectrum disorders, and all non-cannabis substance-related disorders will be exclusionary. However, anxiety disorders, obsessive-compulsive disorder (OCD), and post-traumatic stress disorder (PTSD) are not uncommon among depressed individuals and will be allowed as long as depressive symptoms are primary. Our focus on behavioral constructs aims to address comorbidity and mechanistic overlap among psychiatric disorders. Were these diagnoses exclusionary, the sample would be highly atypical of depression.
  • Self-injurious acts (e.g. cutting) and suicidal ideations (SI) without a specific plan (defined as passive SI) are common in adolescent depression and will be allowed. However, if SI constitutes an imminent risk to self or others (defined as active SI), the adolescent will be withdrawn from the study and emergency procedures will be initiated immediately, including ER admission (see Protection of Human Subjects).

Healthy controls will have no lifetime history of any major psychiatric diagnoses and no use of any THC.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Neuroimaging Investigation Group
Participants in this group will receive neuroimaging investigation for up to 2 years.
Participants will undergo fMRI neuroimaging at two timepoints, at the start of the study and at the 1 year follow up. The fMRI is one hour in duration. During the fMRI, participants will complete two tasks investigating diverse aspects of reward circuitry activity. After this is completed, participants will be followed up for another year clinically.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Depression Severity measured by the Beck Depression Inventory (BDI)
Time Frame: Up to 3 years
Scores range from 0-63 with a higher score indicating higher depression severity
Up to 3 years
Anhedonia Severity measured by the Temporal Experience of Pleasure Scale (TEPS)
Time Frame: Up to 3 years
Scores range from 18-108 with a higher score indicating higher Anhedonia severity
Up to 3 years
Cannabis Use measured by the Daily Frequency, Age of Onset, and Quantity of Cannabis Use (DFAQCU) Inventory
Time Frame: Up to 3 years
Scores range from 1-15 with a higher score indicating more Cannabis Use
Up to 3 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Depression Severity measured by the Montgomery-Åsberg Depression Rating Scale (MADRS)
Time Frame: Up to 3 years
Scores range from 0-60 with a higher score indicating higher depression severity
Up to 3 years
Depression Severity measured by the Convergence of Children's Depression Rating Scale-revised (CDRSR)
Time Frame: Up to 3 years
Scores range from 17-113 with a higher score indicating higher depression severity
Up to 3 years
Anhedonia Severity measured by the Snaith-Hamilton Pleasure Scale (SHAPS)
Time Frame: Up to 3 years
Scores range from 0-14 with a higher score indicating higher Anhedonia severity
Up to 3 years
Cannabis Use measured by the Cannabis Use Problems Identification Test (CUPIT)
Time Frame: Up to 3 years
Scores range from 0-18 with a higher score indicating more Cannabis Use
Up to 3 years
Cannabis Use measured by a quantitative cannabinoid metabolites urine analysis
Time Frame: Up to 3 years
will be measured in microgram per liter
Up to 3 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Vilma Gabbay, MD, JD, MS, University of Miami

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 4, 2025

Primary Completion (Estimated)

June 1, 2029

Study Completion (Estimated)

June 1, 2029

Study Registration Dates

First Submitted

April 15, 2025

First Submitted That Met QC Criteria

April 15, 2025

First Posted (Actual)

April 23, 2025

Study Record Updates

Last Update Posted (Actual)

April 22, 2026

Last Update Submitted That Met QC Criteria

April 20, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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