- Brain Measures [ Time Frame: Visits 3-5: For approximately 60 mins each visit ] [ Designated as safety issue: No ]
functional magnetic resonance imaging (fMRI) blood oxygen level-dependent (BOLD) percent signal change within region of interests [amygdala; ventromedial prefrontal cortex; hippocampus].
- Psychophysiology [ Time Frame: Visits 2-5: For approximately 30 mins during Visit 2 and 60 mins during Visits 3-5. ] [ Designated as safety issue: No ]
Skin conductance response (SCR): change in SCR [peak amplitude from 0.5-4.5 sec following stimulus presentation minus average 2 second baseline prior to stimulus presentation].
- Expectancy Ratings [ Time Frame: Visits 2-5: For approximately 30 minutes during Visit 2 and 60 minutes during Visits 3-5. ] [ Designated as safety issue: No ]
To assess the expected likelihood that an aversive cue (e.g. noise burst or shock) will occur or not based on while slide was shown, participants will repeatedly rate their expectancy of the aversive cue using a button box on a scale from 1 to 3 [1 = certain that the aversive cue will be presented; 2 = certain that the aversive cue will not be presented; 3 = uncertain whether the aversive cue will be presented].
- Subjective Units of Distress (SUDS) [ Time Frame: Visits 2-5: taken at three time points throughout the tasks: before the task begins, in the middle of the task, and at the end of the task. Each rating takes no more than 5 seconds ] [ Designated as safety issue: No ]
Subjective Units of Distress (SUDS): used to measure fear ratings/”subjective” anxiety on a scale from 0-100
- Visual Analogue Scale of Mood [ Time Frame: Visit 3: These measures are collected immediately before capsule ingestion (Time 0), and 30, 60, 120, 180, and 240 minutes afterwards. This rating takes approximately 5 minutes to complete. ] [ Designated as safety issue: No ]
Visual Analog Scales (VAS): Subjective ratings of mood and drug effects on a 0-100.
- Drug Effects Questionnaire [ Time Frame: Visits 3 & 4: During Visit 3, collected immediately before capsule ingestion (Time 0), and 30, 60, 90, 120, 150, 180, and 240 minutes and 8 hours. Will also be collected 24 hours after drug administration on Visit 4. ] [ Designated as safety issue: No ]
Drug Effects Questionnaire (DEQ): Subjective ratings of drug effects on from 1-5 on the following scales: “Feel”, “High”, and “Like”.
- Addiction Research Center Inventory [ Time Frame: Visit 3: These measures are collected immediately before capsule ingestion (Time 0), and 30, 60, 120, 180, and 240 minutes afterwards. This rating takes approximately 5 minutes to complete. ] [ Designated as safety issue: No ]
Addiction Research Center Inventory (ARCI): A standardized questionnaire for assessing subjective effects of psychoactive drugs. Used to differentiate drug effects from placebo.
- State-Trait Anxiety Inventory [ Time Frame: Visit 3: These measures are collected immediately before capsule ingestion (Time 0), and 30, 60, 120, 180, and 240 minutes afterwards. This rating takes approximately 5 minutes to complete. ] [ Designated as safety issue: No ]
Spielberger Trait/State Anxiety Inventory (STAI): Measure of trait and state anxiety.
- End of Session Questionnaire [ Time Frame: Visit 3: Completed at the end of Visit 3 (240 min post drug ingestion). Takes approximately 2 minutes to complete. ] [ Designated as safety issue: No ]
Participants will complete the End of Session Questionnaire (ESQ), which includes question regarding overall drug effects during the session and asks participants to indicate whether they think they received active drug or placebo.
- Heart Rate [ Time Frame: Visit 3: Heart rate is collected immediately before capsule ingestion (Time 0), and 30, 60, 120, 180, and 240 minutes afterwards. This assessment takes approximately 1 minute. ] [ Designated as safety issue: No ]
Heart rate will be collected at regular intervals throughout Visit 3.
- Blood Pressure [ Time Frame: Visit 3: Blood pressure is collected immediately before capsule ingestion (Time 0), and 30, 60, 120, 180, and 240 minutes afterwards. This assessment takes approximately 1 minute. ] [ Designated as safety issue: No ]
Blood pressure will be collected at regular intervals throughout Visit 3.
The total time that for each participant involved in this study is 5 visits, as outlined below:
Visit 1: Questionnaires, Screening, and Orientation: During this visit the potential participant will learn about the study procedures, sign the informed consent documents, and fill out a packet of forms that ask about his or her race and ethnic background, use of drugs and alcohol and physical and mental health.
Visit 2: Behavioral Tests: During this visit the participant will complete several computer tasks, and the study staff will be measuring reaction time and psychophysiological measures.The tasks that the participant will perform will show three different images and an aversive stimulus (e.g. loud burst of noise or animated snake) may follow one image most of the time, while the other images may never be followed by the aversive cue. The participant will need to try to predict whether the aversive cue will occur or not based on which image is shown and will be asked to repeatedly rate on a scale how likely it is that he or she thinks an aversive cue will occur after each image. Lastly, during the session the participant will also be asked to report his or her level of anxiety on a scale from 0 to 100.
Visit 3: Behavioral Tests with Drug or Placebo and Magnetic Resonance (MR) scan: For safety reasons participant will not be allowed to take any drugs for at least 24 hours before this visit, and should not use marijuana for at least 2 weeks before. Participants will be required to pass a urine drug test (and pregnancy test for women) and breathalyzer test before being allowed to continue with this visit. The participant will also not be allowed to drive himself or herself home from this visit, so he or she should arrange a friend or family member to pick him or her up or a taxi can be called by our research staff.
The participant will view the same images he or she did on the previous day (Visit 2), and may experience the same aversive stimulus as during Visit 2. The participant will again be asked to rate how much he or she expects to experience the aversive stimulus after each image and he or she will also be asked to report his or her level of anxiety on a scale from 0 to 100. However, about 2 hours before the task begins, the participant will be asked to swallow a capsule containing either a marijuana-like drug (Dronabinol) or a placebo (sugar pill). Dronabinol is a Food & Drug Administration (FDA) approved drug and the doses (5mg or 10mg; one time) are unlikely to have any effects that last beyond the duration of the study visit. About every 30 minutes after taking the pill, the participant will fill out some questionnaires about mood and how he or she is feeling at the moment.
Visit 4: Behavioral Tests and MR scan: This visit will be very similar to Visit 2. Participants will participate in the same type of task inside the MR scanner, while the study staff measures reaction time and psychophysiological responding and brain activation. Participants will view the same images he or she did previously, and may experience the same aversive stimulus as during Visit 2. Participants will again be asked to rate how much they expect to experience the aversive stimulus after each image and will also be asked to report their level of anxiety on a scale from 0 to 100.
Visit 5: Behavioral Tests and MR scan: This visit will occur approximately 1 week after Visit 4 and will have the same procedure. Participants will participate in the same type of task inside the MR scanner, while the study staff measures reaction time and psychophysiological responding and brain activation. Participants will again be asked to rate how much they expect to experience the aversive stimulus after each image and will also be asked to report their level of anxiety on a scale from 0 to 100.