Cannabis UseNCT03276221

Cognitive Recovery With Cannabis Abstinence Among High School-Aged Adolescents

A study testing Abstinence in people with Cannabis Use and Cognitive Change, run by Massachusetts General Hospital at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

This study will use a randomized controlled design to test whether 30 days of cannabis abstinence, compared to 30 days of monitoring, is associated with improvements in cognitive functioning. Non-using controls will also be enrolled to determine the clinical significance of any cognitive improvements with abstinence. Read more about this study

Who is it for?: Ages 10 to 19 yearsHealthy volunteers can take part
Conditions the study is for: Cannabis Use, Cognitive Change, Adolescent Behavior
What is being tested?: Abstinence
Type of treatment: Lifestyle or therapy programme
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 201 participants
Where: 1 siteUnited States
Study dates: 7 Aug 2017to 9 Nov 2022
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 10 to 19 years
All sexes
Healthy volunteers accepted
Child, Adult

Who may be able to join

None listed.

Who cannot join

Passive consent for initial school-wide assessment withdrawn by parent or legal guardian or written parental consent not provided prior to screening

Trial locations and contacts

1 site in 1 country.

United States1 site

Massachusetts General Hospital
Boston, Massachusetts, 02114

Other trials in United States

About this study

Read the detailed description

This is a 5-year randomized, longitudinal trial of cannabis abstinence designed to determine (1) if performance improves with abstinence beyond that observed with continued cannabis use, and if so, (2) when during abstinence cognitive improvement occurs, and (3) whether performance in abstinent individuals "returns" to performance levels observed in non-using peers. We hypothesized that abstinent adolescent cannabis users would have more neurocognitive improvement over four weeks compared to non-abstinent cannabis users, and performance would continuously improve throughout four weeks of abstinence. We will recruit 210 adolescents with and without regular cannabis use. Eligible cannabis users will be randomized to either a contingency management intervention which will incentivize 4 weeks of cannabis abstinence (n = 70), or non-contingent monitoring with no abstinence requirement (n = 70). All participants (including non-users; n = 70) will complete cognitive assessments, toxicology testing, self-report questionnaires and semi-structured mood and substance use interviews during the 4-week study as well as one 30-day follow-up visit. Abstinence will be indexed by decreasing levels of cannabis metabolites in urine.

Conditions: Cannabis Use, Cognitive Change, Adolescent Behavior
Being tested: Abstinence
Medical subject headings: Adolescent Behavior

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

AbstinenceBehavioural
Also called Contingency Management
Cannabis users randomized to this condition will be enrolled in a contingency management intervention for 30 days of cannabis abstinence.

Study groups in NCT03276221
Study group	Role	What they receive
Abstinent	Active comparator	This group of cannabis users are agree to remain abstinent from cannabis use for 30 days. Receives: Behavioral: Abstinence
Monitoring	No intervention	This group of cannabis users are not asked to change their cannabis use behavior.
Non-Users	No intervention	This is a group of adolescents with little to no cannabis use history and is non-randomized.

What is being measured

The primary outcome is the main question the study is designed to answer.

Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4
The number of times the subject chose the incorrect box for a stimulus on assessment problems plus an adjustment for the estimated number of errors they would have made on any problems/attempts/recalls they did not reach. This is a specific measure from the Paired Associates Learning (PAL) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The PAL module assesses visual memory and new learning. Count variable, ranging from 0 to 70, where higher scores indicate more errors and worse performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in First Attempt Memory Score From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4
The number of times a subject chose the correct box on their first attempt when recalling pattern locations, which was calculated across all trials. This is a specific measure from the Paired Associates Learning (PAL) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The PAL module assesses visual memory and new learning. Count variable, ranging from 0 to 20, where higher scores indicate better memory performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in Forward Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4
The longest length of sequences (spans) a subject successfully remembered in the original order. This is a specific measure from the Spatial Span (SSP) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SSP assesses visuospatial working memory capacity. Count variable, ranging from 2 to 9, with higher scores indicating better memory performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in Reverse Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4
The longest length of sequences (spans) a subject successfully remembered in the reverse order. This is a specific measure from the Spatial Span (SSP) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SSP assesses visuospatial working memory capacity. Count variable, ranging from 2 to 9, with higher scores indicating better memory performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Total Number Correct in the Immediate Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of distinct words a subject correctly recalled from the studied list of 18 words during the immediate free recall phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 18, with higher scores indicating better immediate recall performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Total Number Correct in the Delayed Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of distinct words a subject correctly recalled from the studied list of 18 words during the delayed free recall phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 18, with higher scores indicating better immediate recall performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Total Number Correct in the Immediate Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of words a subject correctly identified as either previously studied or novel during the immediate recognition phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 36, with higher scores indicating better recognition memory performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Total Number Correct in the Delayed Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of words a subject correctly identified as either previously studied or novel during the delayed recognition phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 36, with higher scores indicating better recognition memory performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Total Number Incorrect From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of words a subject correctly identified as either previously studied or novel during the delayed recognition phase. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Count variable, ranging from 0 to 160, with higher scores indicating more errors and worse performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Response Latency From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
The response latency for each participant was defined as a summary (median) computed over their response times for all correct responses irrespective of condition. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Response time variable in milliseconds (ms), ranging from 100 to 2000 ms, with higher values indicating slower performance across all trials.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Incongruency Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
The incongruency cost for each participant was defined as a summary (median) of response times for incongruent trials minus a summary (median) of response times for congruent trials. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Difference score in milliseconds (ms), ranging from -1900 to 1900 ms, with higher values indicating slower responses on incongruent trials, suggesting that it takes longer to process conflicting information.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Multitasking Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
The multitasking cost for each participant was defined as a summary (median) of response times for the multi-task blocks (trials alternated between having to respond to the direction or position of the arrow) minus a summary (median) of response times for the single-task blocks (all trials consisted of either responding to the direction or position of the arrow). This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Difference score in milliseconds (ms), ranging from -1900 to 1900 ms, with higher values indicating slower responses on multi-task blocks, suggesting that it takes longer to process multiple sources of information.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in Number of Problems Correctly Solved on the First Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of trials where the subject chose the correct answer on the first attempt. This is a specific measure from the One Touch Stockings of Cambridge (OTS) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The OTS module assesses executive function based upon the Tower of Hanoi test. Count variable, ranging from 0 to 15, with higher scores indicating better performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Latency to First Correct Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4
The latency to first correct choice for each participant was defined as a summary (median) of the response times for all trials in which the subject picked the correct choice on the first attempt. This is a specific measure from the One Touch Stockings of Cambridge (OTS) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The OTS module assesses executive function based upon the Tower of Hanoi test. Response time variable in milliseconds (ms), a positive unbounded variable, with higher values indicating slower performance across correct trials.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in Stop Signal Reaction Time From Stop Signal Task (SST) Module Averaged Over Weeks 1, 2, 3, and 4
The estimate of the duration at which a person can successfully inhibit a response 50% of the time, represents the time before which all actions become ballistic and a subject is unable to cancel a response selection. This is a specific measure from the Stop Signal Task (SST) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SST module assesses response inhibition (impulse control). Response time variable in milliseconds (ms), ranging from 0 to 500 ms, with higher values indicating that it takes longer for a person to inhibit a response.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Total Number of Between Errors From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4
The number of times a subject incorrectly revisited a box that had contained a token in a previous trial across the 4, 6, and 8 box conditions. This is a specific measure from the Spatial Working Memory (SWM) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SWM module provides a measure of strategy as well as working memory errors. Count variable, ranging from 0 to 63, with higher scores indicating worse performance.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Participant's Strategy for 6-8 Box Conditions From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4
The number of times subjects began a new search from the same box they started on in previous trials. It is assumed that a person who begins from the same box each time is using a planned strategy to find the tokens. This is a specific measure from the Spatial Working Memory (SWM) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SWM module provides a measure of strategy as well as working memory errors. Count variable, ranging from 2 to 14, with higher scores indicating low strategy, meaning a subject began searches from many different boxes.
Measured: 1, 2, 3, and 4 Weeks

Secondary outcomes (2)

Mean Difference in the Measure of Discriminability - A' From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4
A transformation of the proportion of hits and false alarms, providing an estimate of a subject's ability to detect the target sequences of digits after controlling for response bias (i.e., biases to respond or not respond irrespective of the stimuli on screen). This is a specific measure from the Rapid Visual Information Processing (RVP) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The RVP module assesses sustained attention. Bounded continuous variable, ranging from 0 to 1, where higher scores indicate a greater ability to discriminate between targets and distractors.
Measured: 1, 2, 3, and 4 Weeks
Mean Difference in the Reponse Latency for Hits From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4
The response latency for hits for each participant was defined as a summary (median) over the set of response times for all correct responses (identification of target 3-digit sequences). This is a specific measure from the Rapid Visual Information Processing (RVP) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The RVP module assesses sustained attention. Response time variable in milliseconds (ms), ranging from 100 to 1900 ms, with higher values indicating slower performance in detecting targets.
Measured: 1, 2, 3, and 4 Weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

7 Aug 20179 Nov 2022

First posted8 Sep 2017
Study start7 Aug 2017
Primary completion9 Nov 2022
Study completion9 Nov 2022

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (5)Papers the sponsor has linked to this study.
Other trials for Cannabis UseStudies of the same condition, open and under way.
More trials run by Massachusetts General HospitalThe sponsor's other registered studies.
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 N/A
Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Model description: Cannabis users are randomized either to 30 days of cannabis abstinence or 30 days of monitoring with no abstinence requirement. Non-users are not randomized.
Masking: None (open label)
Enrolment: 201 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT03276221
Sponsor's protocol ID: 1K23DA042946
Status last verified: Jan 2024
First submitted: 6 Sep 2017
Last updated: 1 Feb 2024
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No

Publications

Cooke ME, Gilman JM, Lamberth E, Rychik N, Tervo-Clemmens B, Evins AE, Schuster RM. Assessing Changes in Symptoms of Depression and Anxiety During Four Weeks of Cannabis Abstinence Among Adolescents. Front Psychiatry. 2021 Jul 1;12:689957. doi: 10.3389/fpsyt.2021.689957. eCollection 2021.
PubMed 34276449
Savulich G, Rychik N, Lamberth E, Hareli M, Evins AE, Sahakian BJ, Schuster RM. Sex Differences in Neuropsychological Functioning are Domain-Specific in Adolescent and Young Adult Regular Cannabis Users. J Int Neuropsychol Soc. 2021 Jul;27(6):592-606. doi: 10.1017/S1355617720001435.
PubMed 34261559
Schuster RM, Gilman J, Schoenfeld D, Evenden J, Hareli M, Ulysse C, Nip E, Hanly A, Zhang H, Evins AE. One Month of Cannabis Abstinence in Adolescents and Young Adults Is Associated With Improved Memory. J Clin Psychiatry. 2018 Oct 30;79(6):17m11977. doi: 10.4088/JCP.17m11977.
PubMed 30408351
Schuster RM, Potter K, Lamberth E, Rychik N, Hareli M, Allen S, Broos HC, Mustoe A, Gilman JM, Pachas G, Evins AE. Alcohol substitution during one month of cannabis abstinence among non-treatment seeking youth. Prog Neuropsychopharmacol Biol Psychiatry. 2021 Apr 20;107:110205. doi: 10.1016/j.pnpbp.2020.110205. Epub 2020 Dec 9.
PubMed 33309538
Schuster RM, Potter K, Vandrey R, Hareli M, Gilman J, Schoenfeld D, Evins AE. Urinary 11-nor-9-carboxy-tetrahydrocannabinol elimination in adolescent and young adult cannabis users during one month of sustained and biochemically-verified abstinence. J Psychopharmacol. 2020 Feb;34(2):197-210. doi: 10.1177/0269881119872206. Epub 2019 Sep 19.
PubMed 31535597

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 1 Feb 2024. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Cognitive Recovery With Cannabis Abstinence Among High School-Aged Adolescents
ClinicalTrials.gov ID: NCT03276221
Acronym / sponsor ID: 1K23DA042946
Conditions: Cannabis Use, Cognitive Change, Adolescent Behavior
Study type: Interventional
Recruitment status: Completed
Enrolment: 201 participants (actual)
Lead sponsor: Massachusetts General HospitalUniversity, hospital or other
Study start: 7 Aug 2017 (actual)
Primary completion: 9 Nov 2022 (actual)
Study completion: 9 Nov 2022 (actual)
First posted: 8 Sep 2017 (actual)
Results: Posted 1 Feb 2024

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: None (open label)
Number of arms: 3
Model description: Cannabis users are randomized either to 30 days of cannabis abstinence or 30 days of monitoring with no abstinence requirement. Non-users are not randomized.

Arm	Type	Receives
Abstinent	Active comparator	Behavioral: AbstinenceThis group of cannabis users are agree to remain abstinent from cannabis use for 30 days.
Monitoring	No intervention	–This group of cannabis users are not asked to change their cannabis use behavior.
Non-Users	No intervention	–This is a group of adolescents with little to no cannabis use history and is non-randomized.

Who may qualify

Ages: 10 to 19 years
Sex: All
Healthy volunteers: Accepted
Age groups: Child, Adult

Key inclusion criteria (0 listed)

Key exclusion criteria (1 listed)

Passive consent for initial school-wide assessment withdrawn by parent or legal guardian or written parental consent not provided prior to 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
AbstinenceAlso: Contingency ManagementCannabis users randomized to this condition will be enrolled in a contingency management intervention for 30 days of cannabis abstinence.	Behavioural	Abstinent

Primary outcome

Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The number of times the subject chose the incorrect box for a stimulus on assessment problems plus an adjustment for the estimated number of errors they would have made on any problems/attempts/recalls they did not reach. This is a specific measure from the Paired Associates Learning (PAL) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The PAL module assesses visual memory and new learning. Count variable, ranging from 0 to 70, where higher scores indicate more errors and worse performance.
Mean Difference in First Attempt Memory Score From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The number of times a subject chose the correct box on their first attempt when recalling pattern locations, which was calculated across all trials. This is a specific measure from the Paired Associates Learning (PAL) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The PAL module assesses visual memory and new learning. Count variable, ranging from 0 to 20, where higher scores indicate better memory performance.
Mean Difference in Forward Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The longest length of sequences (spans) a subject successfully remembered in the original order. This is a specific measure from the Spatial Span (SSP) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SSP assesses visuospatial working memory capacity. Count variable, ranging from 2 to 9, with higher scores indicating better memory performance.
Mean Difference in Reverse Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The longest length of sequences (spans) a subject successfully remembered in the reverse order. This is a specific measure from the Spatial Span (SSP) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SSP assesses visuospatial working memory capacity. Count variable, ranging from 2 to 9, with higher scores indicating better memory performance.
Mean Difference in the Total Number Correct in the Immediate Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The total number of distinct words a subject correctly recalled from the studied list of 18 words during the immediate free recall phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 18, with higher scores indicating better immediate recall performance.
Mean Difference in the Total Number Correct in the Delayed Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The total number of distinct words a subject correctly recalled from the studied list of 18 words during the delayed free recall phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 18, with higher scores indicating better immediate recall performance.
Mean Difference in the Total Number Correct in the Immediate Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The total number of words a subject correctly identified as either previously studied or novel during the immediate recognition phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 36, with higher scores indicating better recognition memory performance.
Mean Difference in the Total Number Correct in the Delayed Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The total number of words a subject correctly identified as either previously studied or novel during the delayed recognition phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 36, with higher scores indicating better recognition memory performance.
Mean Difference in the Total Number Incorrect From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The total number of words a subject correctly identified as either previously studied or novel during the delayed recognition phase. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Count variable, ranging from 0 to 160, with higher scores indicating more errors and worse performance.
Mean Difference in the Response Latency From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The response latency for each participant was defined as a summary (median) computed over their response times for all correct responses irrespective of condition. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Response time variable in milliseconds (ms), ranging from 100 to 2000 ms, with higher values indicating slower performance across all trials.
Mean Difference in the Incongruency Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The incongruency cost for each participant was defined as a summary (median) of response times for incongruent trials minus a summary (median) of response times for congruent trials. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Difference score in milliseconds (ms), ranging from -1900 to 1900 ms, with higher values indicating slower responses on incongruent trials, suggesting that it takes longer to process conflicting information.
Mean Difference in the Multitasking Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The multitasking cost for each participant was defined as a summary (median) of response times for the multi-task blocks (trials alternated between having to respond to the direction or position of the arrow) minus a summary (median) of response times for the single-task blocks (all trials consisted of either responding to the direction or position of the arrow). This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Difference score in milliseconds (ms), ranging from -1900 to 1900 ms, with higher values indicating slower responses on multi-task blocks, suggesting that it takes longer to process multiple sources of information.
Mean Difference in Number of Problems Correctly Solved on the First Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The total number of trials where the subject chose the correct answer on the first attempt. This is a specific measure from the One Touch Stockings of Cambridge (OTS) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The OTS module assesses executive function based upon the Tower of Hanoi test. Count variable, ranging from 0 to 15, with higher scores indicating better performance.
Mean Difference in the Latency to First Correct Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The latency to first correct choice for each participant was defined as a summary (median) of the response times for all trials in which the subject picked the correct choice on the first attempt. This is a specific measure from the One Touch Stockings of Cambridge (OTS) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The OTS module assesses executive function based upon the Tower of Hanoi test. Response time variable in milliseconds (ms), a positive unbounded variable, with higher values indicating slower performance across correct trials.
Mean Difference in Stop Signal Reaction Time From Stop Signal Task (SST) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The estimate of the duration at which a person can successfully inhibit a response 50% of the time, represents the time before which all actions become ballistic and a subject is unable to cancel a response selection. This is a specific measure from the Stop Signal Task (SST) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SST module assesses response inhibition (impulse control). Response time variable in milliseconds (ms), ranging from 0 to 500 ms, with higher values indicating that it takes longer for a person to inhibit a response.
Mean Difference in the Total Number of Between Errors From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The number of times a subject incorrectly revisited a box that had contained a token in a previous trial across the 4, 6, and 8 box conditions. This is a specific measure from the Spatial Working Memory (SWM) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SWM module provides a measure of strategy as well as working memory errors. Count variable, ranging from 0 to 63, with higher scores indicating worse performance.
Mean Difference in the Participant's Strategy for 6-8 Box Conditions From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
The number of times subjects began a new search from the same box they started on in previous trials. It is assumed that a person who begins from the same box each time is using a planned strategy to find the tokens. This is a specific measure from the Spatial Working Memory (SWM) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SWM module provides a measure of strategy as well as working memory errors. Count variable, ranging from 2 to 14, with higher scores indicating low strategy, meaning a subject began searches from many different boxes.

2 secondary outcomes

Mean Difference in the Measure of Discriminability - A' From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks
Mean Difference in the Reponse Latency for Hits From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4
Time frame: 1, 2, 3, and 4 Weeks

Results and safety

Results posted to the registry on 1 Feb 2024, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Abstinent	64	54
Monitoring	68	66
Non-Users	69	69

Primary outcome: Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4

Time frame: 1, 2, 3, and 4 Weeks. Mean (Standard Deviation). Unit: score on a scale

Measure	Abstinent n = 54	Monitoring n = 66	Non-Users n = 69
Value	5.6 (6.4)	6.2 (7.7)	5.9 (8.1)

Abstinent vs Monitoring: Slope: -0.19, p = 0.215, Mixed Models Analysis

Population analysed: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Plan).

Primary outcome: Mean Difference in First Attempt Memory Score From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4

Time frame: 1, 2, 3, and 4 Weeks. Mean (Standard Deviation). Unit: score on a scale

Measure	Abstinent n = 54	Monitoring n = 66	Non-Users n = 69
Value	16.2 (3.2)	15.8 (3.4)	16.1 (3.6)

Abstinent vs Monitoring: Slope: 0.10, p = 0.495, Mixed Models Analysis

Population analysed: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).

Primary outcome: Mean Difference in Forward Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4

Time frame: 1, 2, 3, and 4 Weeks. Mean (Standard Deviation). Unit: score on a scale

Measure	Abstinent n = 54	Monitoring n = 66	Non-Users n = 69
Value	7.6 (1.3)	7.4 (1.3)	7.6 (1.4)

Abstinent vs Monitoring: Slope: 0.28, p = 0.050, Mixed Models Analysis

Population analysed: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).

Primary outcome: Mean Difference in Reverse Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4

Time frame: 1, 2, 3, and 4 Weeks. Mean (Standard Deviation). Unit: score on a scale

Measure	Abstinent n = 54	Monitoring n = 66	Non-Users n = 69
Value	6.9 (1.4)	7 (1.5)	6.9 (1.6)

Abstinent vs Monitoring: Slope: -0.07, p = 0.532, Mixed Models Analysis

Population analysed: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).

2 secondary outcomes are reported in the full results.

Adverse events

Time frame: Adverse event data was collected over 60 days.. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Abstinent	0 of 54 (0%)	49 of 54 (90.7%)	0 of 54
Monitoring	0 of 66 (0%)	46 of 66 (69.7%)	0 of 66
Non-Users	0 of 69 (0%)	31 of 69 (44.9%)	0 of 69

Limitations and caveats (from the sponsor): Due to the constraints of the COVID-19 pandemic, approximately 6% of all study visits were conducted virtually. Visits were conducted remotely for one of the following reasons: the study site was closed due to hospital policy, the participant tested positive for COVID-19, or they endorsed a COVID-19-related symptom before the study visit. We believe this is a minor limitation of our study since administering the cognitive assessments virtually could have affected data collection.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 1 Feb 2024.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Results publication: PubMed 34276449Cooke ME, Gilman JM, Lamberth E, Rychik N, Tervo-Clemmens B, Evins AE, Schuster RM. Assessing Changes in Symptoms of Depression and Anxiety During Four Weeks of Cannabis Abstinence Among Adolescents. Front Psychiatry. 2021 Jul 1;12:689957. doi: 10.3389/fpsyt.2021.689957. eCollection 2021.
Results publication: PubMed 34261559Savulich G, Rychik N, Lamberth E, Hareli M, Evins AE, Sahakian BJ, Schuster RM. Sex Differences in Neuropsychological Functioning are Domain-Specific in Adolescent and Young Adult Regular Cannabis Users. J Int Neuropsychol Soc. 2021 Jul;27(6):592-606. doi: 10.1017/S1355617720001435.
Results publication: PubMed 30408351Schuster RM, Gilman J, Schoenfeld D, Evenden J, Hareli M, Ulysse C, Nip E, Hanly A, Zhang H, Evins AE. One Month of Cannabis Abstinence in Adolescents and Young Adults Is Associated With Improved Memory. J Clin Psychiatry. 2018 Oct 30;79(6):17m11977. doi: 10.4088/JCP.17m11977.
Results publication: PubMed 33309538Schuster RM, Potter K, Lamberth E, Rychik N, Hareli M, Allen S, Broos HC, Mustoe A, Gilman JM, Pachas G, Evins AE. Alcohol substitution during one month of cannabis abstinence among non-treatment seeking youth. Prog Neuropsychopharmacol Biol Psychiatry. 2021 Apr 20;107:110205. doi: 10.1016/j.pnpbp.2020.110205. Epub 2020 Dec 9.
Results publication: PubMed 31535597Schuster RM, Potter K, Vandrey R, Hareli M, Gilman J, Schoenfeld D, Evins AE. Urinary 11-nor-9-carboxy-tetrahydrocannabinol elimination in adolescent and young adult cannabis users during one month of sustained and biochemically-verified abstinence. J Psychopharmacol. 2020 Feb;34(2):197-210. doi: 10.1177/0269881119872206. Epub 2019 Sep 19.

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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. This study is not recruiting at the moment.

Randi M Schuster, PhD principal investigator

Massachusetts General Hospital

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A study testing Abstinence in people with Cannabis Use and Cognitive Change, run by Massachusetts General Hospital at 1 site in United States.

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 0 inclusion and 1 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: finished, as of the sponsor's last update on 1 Feb 2024. 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 United States. 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 1 Feb 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 (time frame: 1, 2, 3, and 4 Weeks). The study lists 17 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03276221, which also lists 5 linked publications.

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 1 Feb 2024.