Clinical Trial Details
— Status: Recruiting
Administrative data
| NCT number |
NCT06264791 |
| Other study ID # |
STUDY00018516 |
| Secondary ID |
K99AA030591 |
| Status |
Recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
February 1, 2024 |
| Est. completion date |
October 1, 2024 |
Study information
| Verified date |
February 2024 |
| Source |
University of Washington |
| Contact |
Jonas Dora, PhD |
| Phone |
206-741-6330 |
| Email |
jdora[@]uw.edu |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The goal of this experimental study is to improve our understanding of the effects of stress
on the decision to consume (more) alcohol in regular drinkers. The main question[s] it aims
to answer are:
- Does psychological stress affect the decision to consume (more) alcohol?
- How does psychological stress affect the decision to consume (more) alcohol?
Participants will be randomly assigned to one of four conditions (stress alcohol, stress
no alcohol, no stress alcohol, no stress no alcohol) and complete a value-based
decision-making task twice (once before and once after the manipulations).
Description:
In this study, the investigators will explore whether and how the decision between consuming
an alcoholic or non-alcoholic drink is influenced by a stressful event and by being already
intoxicated.
Behavioral data:
Our first set of hypotheses tests whether the decision is influenced by stress and alcohol
intoxication:
H1a: Stress affects the decision between alcoholic and non-alcoholic drinks, so that
participants in the stress conditions choose alcoholic over non-alcoholic drinks more often
compared to participants in the no stress conditions.
H1b: Alcohol intoxication does not affect the decision between alcoholic and non-alcoholic
drinks.
H1c: The effect of stress on the decision between alcohol and non-alcoholic drinks is
modulated by alcohol intoxication, so that the effect of stress is stronger for participants
that are intoxicated.
H2a: Stress affects the reaction time for decisions between alcoholic and non-alcoholic
drinks, so that participants in the stress condition make choices between alcoholic and
non-alcoholic drinks faster compared to participants in the no stress condition.
H2b: Alcohol intoxication affects the reaction time for decisions between alcoholic and
non-alcoholic drinks, so that participants in the alcohol condition make choices between
alcoholic and non-alcoholic drinks faster compared to participants in the no alcohol
condition.
H2c: The effect of stress on the reaction time for decisions between alcohol and on-alcoholic
drinks is modulated by alcohol intoxication, so that the effect of stress is stronger for
participants that are intoxicated.
Drift diffusion modeling:
Our second set of hypotheses test how the decision might be influenced by stress and
intoxication. The investigators do not have directional hypotheses for these analyses but the
following global predictions:
H3a: Stress affects at least one of three DDM (drift diffusion model) parameters (drift rate,
boundary, bias). The investigators have no a priori prediction which parameter will be most
affected by stress.
H3b: Alcohol intoxication affects at least one of three DDM parameters (drift rate, boundary,
bias). The investigators have no a priori prediction which parameter will be most affected by
alcohol intoxication.
H3c: Stress and alcohol intoxication have an interactive effect on the DDM parameter(s) most
affected by stress and alcohol. The investigators have no a priori prediction which parameter
will be most affected by the interaction.
The investigators will do a 2x2 between-subjects experiment. Participants will be randomly
assigned to one of four groups (stress and alcohol condition, no stress and alcohol
condition, stress and no alcohol condition, no stress and no alcohol condition). This is the
experimental procedure:
1. Participants will perform an image rating task, value-based decision-making task, and
psychomotor vigilance task (described below).
2. Participants will undergo the beverage administration (alcohol vs no alcohol; described
below).
3. Participants will undergo the stress induction (stress vs no stress; described below).
4. Participants will perform the value-based decision-making task and psychomotor vigilance
task again and will perform the alcohol purchase task.
Block randomization will be used to randomly assign participants to conditions while ensuring
balanced sample sizes in all 4 conditions.
Participants will be recruited from the community via advertisements in public places around
Seattle as well as online ads.
Upon responding to one of our ads, participants will complete an online screening survey to
check for our inclusion/exclusion criteria. Eligibility will be confirmed via a phone call to
the participant. If assigned to the stress condition, next they will perform the stress
induction interview (described below). All participants will then come to the bar lab to
complete the lab session.
The investigators explored power for a 2x2 between-subjects ANOVA (with the ANOVA_exact Shiny
app) with the following means (sd = 0.1 for all cells), which creates two main effects and an
interaction:
a1_b1 = 1.5 a1_b2 = 1.35 a2_b1 = 1.55 a2_b2 = 1.5 These are reasonable values chosen (for
drift rate) based on our previous work and create an effect size of eta-squared = .06 for the
interaction effect, which The investigators consider a medium-sized effect. This gives us
power = 87.86 with N = 40 per condition.
Intoxication: Participants randomly assigned to the alcohol condition will be administered
100-proof Vodka mixed with orange juice (1:3 ratio) to induce a BAC (Blood Alcohol
Concentration) of .06% (based on Widmark's formula). They will be breathalyzed every 5
minutes until they reach peak BAC, at which point they will continue with the experiment.
Participants randomly assigned to the no alcohol condition will be administered water mixed
with orange juice (1:3 ratio). Each participant in the no alcohol condition will be yoked to
a participant in the alcohol condition and will complete the same number of breath tests.
Once participants in the alcohol condition reach peak BAC and participants in the no alcohol
condition performed the same number of breath tests as the participant they are yoked to,
participants will continue to the stress induction.
Stress: To manipulate stress, The investigators follow the personalized imagery script
procedure developed by Sinha and colleagues. Participants randomly assigned to the stress
condition will be interviewed about one week prior to the lab session. The participants will
share a detailed description of a stressful event from their life (last 12 months) with the
interviewer. Based on this interview, the experimenter will write a script (~500 words), that
will then be audiotaped. Participants will listen to this personalized audiotape during the
experiment, and will be asked to imagine this event as vividly as possible. Participants
randomly assigned to the no stress condition will listen to a generic audiotape that
describes a non-stressful event (~500 words). The participants will not be interviewed.
During the lab session, participants will first complete a 3-min color counting task. The
participant will then listen to the audiotape (personalized stressful audiotape in stress
condition, generic non-stressful audiotape in no stress condition). The stress induction will
be checked via two self-report items that ask the participant to report their current
experience of stress and mood before and after listening to the audiotape.
Image rating task: Participants will view 30 images of alcoholic drinks and 30 images of
non-alcoholic drinks and will indicate for each item how much the participants like to
consume them (1 = not at all, 2 = not really, 3 = a little bit, 4 = a lot). These ratings
will be used to create the VBDM (value-based decision-making) trials. Participants will
perform this task twice, once before and once after the manipulations.
Value-based decision-making task: On each trial, participants will be presented with one
alcoholic drink and one non-alcoholic drink image side-by-side. Participants will never be
presented with two images the participants gave the same initial rating. The difference in
value will be balanced (there will be an equal number of trials where the initial rating
difference is 3, 2, and 1 in favor of alcohol and non-alcoholic drink respectively). The side
on which the correct choice appears will be randomized. Participants will have 4 seconds to
decide which one the participants would rather like to consume right now by pressing a
corresponding button on their keyboard ('Z' for left and 'M' for right option). Participants
will complete a total of 360 trials, with a short break after 180 trials. The participants
will be instructed to respond as quickly as possible while making sure the participants
choose the one the participants would rather want to consume in that moment. Trials will be
separated by the display of a fixation cross for 250ms. Participants will perform this task
twice, once before and once after the manipulations.
Psychomotor vigilance task: After the VBDM task, participants will perform a 3-minute PVT
(psychomotor vigilance task). A stimulus will appear on the screen in random intervals
between 2 and 10 seconds. Participants are instructed to press the spacebar in response to
the stimulus appearing as quickly as possible. Participants will perform this task twice,
once before and once after the manipulations.
Alcohol purchase task: For exploratory purposes, participants will complete the Alcohol
Purchase Task. Participants will report how many drinks the participants would consume right
now if they cost $0-$15 (increments of $1).
