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| ID | Type | Description | Link |
|---|---|---|---|
| R21MH093917 | U.S. NIH Grant/Contract | View source |
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| Name | Class |
|---|---|
| National Institute of Mental Health (NIMH) | NIH |
| National Institutes of Health (NIH) | NIH |
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The goal of the current proposal is to investigate the effects of a cannabinoid drug on the memory of extinguished fear in humans and the brain circuitry important for the recall of extinction learning. The investigators findings will translate previous discoveries from animal studies to humans and increase their understanding of the neurobiological mechanisms supporting retention of extinction memory. This proof-of-concept study is a critical translational first step towards the development of cannabinoid modulators as an adjunctive strategy to exposure-based therapies to augment extinction learning and prevent the return of fear memories in patients with post-traumatic stress and other anxiety disorders.
The inability to suppress inappropriate fear responses is the hallmark of anxiety disorders, such as posttraumatic stress disorder (PTSD), panic, and phobia disorders. Extinction of fear occurs during exposure therapy; however, this is temporary and fear often re-emerges with the passage of time (spontaneous recovery), undermining the maintenance of therapeutic gains. Enhancing the neural and neurochemical substrates involved in retention of extinction memory will be critical to solving this challenge. Animal studies have shown that activation of the cannabinoid system within the amgydala, hippocampus, and ventromedial prefrontal cortex (AMYG, HPC, vmPFC, respectively), brain structures critical to fear expression and extinction learning, enhances fear extinction and its retention. Specifically, CB1 receptor agonists, such as Δ9-tetrahydrocannibinol (THC), can facilitate extinction recall by preventing recovery of extinguished fear in rats. However, this phenomenon has not been, but should be, investigated in humans. This proof-of-concept project specifically aims to assess the effects of THC on the recall of extinction learning and underlying neural circuit activation (HPC, vmPFC) when tested 24 hours and 1 week after extinction training, and to determine if the maintenance of extinction retention (1 week later) is mediated by the enhancement of vmPFC-HPC activation by THC observed during a recall test 24 hours after extinction learning. In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI and simultaneous skin conductance recordings with an acute pharmacological challenge with oral, synthetic THC prior to extinction learning in healthy adult volunteers (n=80) and test extinction retention and maintenance of extinction learning at 24 hours and 1 week later, as well as fear renewal. This proof-of-concept study provides the most translational, impactful, informative, and critical test and first step towards the development of cannabinoid modulators as an adjunctive strategy to exposure-based therapies to augment extinction retention and prevent the return of fear memories in patients with PTSD and other anxiety disorders.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Placebo | Placebo Comparator | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning. |
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| Dronabinol | Active Comparator | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Dronabinol | Drug | Dronabinol (7.5mg) is administered only once by the oral route and is placed in opaque capsules with dextrose filler. Half of the participants will receive dronabinol. |
| Measure | Description | Time Frame |
|---|---|---|
| BOLD Signal Measured by Functional Magnetic Resonance Imaging (fMRI) | Mean BOLD hippocampal signal during extinction learning and retention task in brain responsebetween the placebo (PBO) and the dronabinol (THC) group. Target areas are analyzed from fMRI scans. The scans were completed on days 1, 2, 3, and 9. Participants were randomized to the PBO and THC condition and received either placebo or dronabinol on day 2, 2 hours prior to extinction learning. Data from days 1, 2, 3, & 9 was combined and a single value was averaged for each group. | Day 1, 2, 3, & 9 |
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Inclusion Criteria:
Exclusion Criteria:
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Participants completed initial screening visit, signed consent, if eligible scheduled for 4 fMRI scans. Participants were randomized immediately before the 2nd fMRI scan. Reasons for exclusion prior to randomization: 6 excluded during initial screening, 13 lost to follow up, 5 did not want to take study drug, 11 had scheduling conflicts.
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| ID | Title | Description |
|---|---|---|
| FG000 | Placebo | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning. Placebo: Placebo is administered only once by the oral route and contains only dextrose in opaque capsules. Half of the participants will receive placebo. |
| FG001 | Dronabinol | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning Dronabinol: Dronabinol (7.5mg) is administered only once by the oral route and is placed in opaque capsules with dextrose filler. Half of the participants will receive dronabinol. |
| Title | Milestones | Reasons Not Completed | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
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| ID | Title | Description |
|---|---|---|
| BG000 | Placebo | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning. Placebo: Placebo is administered only once by the oral route and contains only dextrose in opaque capsules. Half of the participants will receive placebo. |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Customized | Between 21-45 years |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | BOLD Signal Measured by Functional Magnetic Resonance Imaging (fMRI) | Mean BOLD hippocampal signal during extinction learning and retention task in brain responsebetween the placebo (PBO) and the dronabinol (THC) group. Target areas are analyzed from fMRI scans. The scans were completed on days 1, 2, 3, and 9. Participants were randomized to the PBO and THC condition and received either placebo or dronabinol on day 2, 2 hours prior to extinction learning. Data from days 1, 2, 3, & 9 was combined and a single value was averaged for each group. | The number of participants analyzed is 22 in the placebo group and 18 in the dronabinol group. The total number of participants who completed all 4 scanning sessions is 44. 4 participants were excluded from data analysis due to having poor quality fMRI data from any of the four sessions. | Posted | Mean | Standard Deviation | parameter estimates (arbitrary units) | Day 1, 2, 3, & 9 |
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Placebo | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning. Placebo: Placebo is administered only once by the oral route and contains only dextrose in opaque capsules. Half of the participants will receive placebo. |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Dr. K. Luan Phan | University of Illinois at Chicago | 312-355-5954 | klphan@psych.uic.edu |
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| ID | Term |
|---|---|
| D013759 | Dronabinol |
| D000073893 | Sugars |
| ID | Term |
|---|---|
| D002186 | Cannabinoids |
| D013729 | Terpenes |
| D006838 | Hydrocarbons |
| D009930 | Organic Chemicals |
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| Placebo | Drug | Placebo is administered only once by the oral route and contains only dextrose in opaque capsules. Half of the participants will receive placebo. |
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| BG001 | Dronabinol | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning Dronabinol: Dronabinol (7.5mg) is administered only once by the oral route and is placed in opaque capsules with dextrose filler. Half of the participants will receive dronabinol. |
| BG002 | Total | Total of all reporting groups |
| participants |
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| Sex: Female, Male | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Count of Participants | Participants |
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| Race (NIH/OMB) | Count of Participants | Participants |
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In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning. Placebo: Placebo is administered only once by the oral route and contains only dextrose in opaque capsules. Half of the participants will receive placebo. |
| OG001 | Dronabinol | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning Dronabinol: Dronabinol (7.5mg) is administered only once by the oral route and is placed in opaque capsules with dextrose filler. Half of the participants will receive dronabinol. |
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| 0 |
| 24 |
| 0 |
| 24 |
| EG001 | Dronabinol | In a randomized, double-blind, placebo-controlled, between-subjects design, the investigators will couple a standard Pavlovian fear extinction paradigm in fMRI with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo 2 hours prior to extinction learning in healthy adult volunteers and test extinction retention and maintenance 24 hours and 1 week later, respectively, after extinction learning Dronabinol: Dronabinol (7.5mg) is administered only once by the oral route and is placed in opaque capsules with dextrose filler. Half of the participants will receive dronabinol. | 0 | 26 | 0 | 26 |
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| D002241 |
| Carbohydrates |