Brain Imaging of Cannabinoid Receptors

Early Phase 1

Completed

Brief Summary: All participants will be healthy volunteers and all procedures will be completed for research purposes only. Two groups will be recruited, females who use cannabis (marijuana, MJ), and female who do not use cannabis (controls). Female MJ users will be enrolled in a protocol that includes an outpatient drug administration session and a 4-day/3-night inpatient stay on the Johns Hopkins Bayview Clinical Research Unit (CRU). During outpatient visits, MJ users will have an MRI, and complete MJ self-administration and cognitive performance sessions. MJ users will then reside on the CRU,and complete MJ abstinence, and self-report instruments for withdrawal discomfort. A positron emission tomography (PET) scan of brain cannabinoid type 1 receptors will also be completed. Non-users will complete MRI, PET imaging and cognitive testing under an outpatient protocol (no MJ administration).

Detailed Description: The primary goals of this project are to examine whether use of cannabis alters brain cannabinoid type 1 receptor (CB1R) availability in females, and if severity of cannabis withdrawal is correlated with CB1 receptor availability. CB1R are widely distributed in the human brain and can be quantified using PET imaging with the radiotracer 11C-OMAR (Carbon-11-OMAR). The effects MJ use on brain CB1R have not been studied in females. The current study will enroll 10 female MJ users in an inpatient protocol that includes administration of smoked MJ, followed by monitored abstinence with daily behavioral assessments, and PET imaging with 11C-OMAR. PET data will collected in 10 matched controls for comparison. The proposed study is an important first step to determine whether localized CB1R changes in female MJ users help explain, and provide a neurobiological target for intervention. Results will increase knowledge of cannabinoid mechanisms of cannabis use and severity of dependence in females, an understudied population.

Recruitment & Eligibility

Inclusion Criteria

Not provided

Exclusion Criteria

< 5th grade reading level
Current Diagnostic and Statistical Manual, version 5 (DSM-5) psychiatric disorder;
Current DSM-5 alcohol or substance use disorder (excluding MJ or nicotine)
Recent Illicit drug use or positive drug test
Using MJ under the guidance of MD;
History of seizures, closed head trauma;
unstable hypertension;
conditions preventing magnetic resonance imaging (MRI) such as implanted metal, claustrophobia, or anatomical abnormalities (e.g., enlarged ventricles, brain lesions);
Use of medications or herbal supplements which may be counter indicated as determined by study physician
Have had exposure to ionizing radiation that in combination with the study's estimated radiation exposure would result in a cumulative exposure that exceeds recommended exposure limits of 5 rem per year.
Presence or history of drug allergy, or allergic disease diagnosed and treated by a physician.
any serious medical condition in whom participation is contraindicated.

Arm && Interventions

Group	Intervention	Description
Nonuser controls	11C-OMAR	No cannabis administration. Non-user controls will complete a PET scan where 20 millicuries of 11C-OMAR
Cannabis users	11C-OMAR	Smoked Cannabis plant material (0 and 25 mg THC) will be administered to volunteers who are regular cannabis users. Cannabis users will also complete a PET scan where 20 millicurie of 11C-OMAR
Cannabis users	Cannabis	Smoked Cannabis plant material (0 and 25 mg THC) will be administered to volunteers who are regular cannabis users. Cannabis users will also complete a PET scan where 20 millicurie of 11C-OMAR

Primary Outcome Measures

Name	Time	Method
Distribution Volume (VT)	Collected during 90-min PET study	Distribution Volume (VT) is the quantification of 11C-OMAR binding to the CB1R; Per our statistical plan we examined VT for eight volumes of interest in the brain (ventral striatum, amygdala, putamen, cingulate, globus pallidus, insula, frontal cortex, and hippocampus) as well as the composite VT for the brain. The unit of measure is mL/cm\^3.

Secondary Outcome Measures

Name	Time	Method
Peak Change From Baseline Marijuana Withdrawal Discomfort Score	Up to 5 days	Marijuana withdrawal discomfort will be self-reported using the marijuana withdrawal checklist, available via PhenXToolkit.org. Items are: depressed mood, irritability, nervousness/anxiety, restlessness, increased aggression, increased anger, violent outbursts, nausea, decreased appetite, stomach pain, shakiness, sweating, sleep difficulty, strange/wild dreams, craving to smoke cannabis, diarrhea/loose stools, dizziness, muscle spasms/aches, hiccups, stuffy nose, feverish feeling, hot flashes, chills, increased appetite, headaches, fatigue/tiredness, yawning, difficulty concentrating, general physical discomfort, and other. Each item is rated as 0=none, 1=mild, 2=moderate, or 3=severe. A sum score is calculated from items that are valid, reliable cannabis withdrawal symptoms (Budney et al, 2003, Journal of Abnormal Psychology,112(3): 393-402). A higher score represents more severe withdrawal. Scores range from 0-36.