CARS: Cannabis and Alcohol Reduction Study

BEHAVIORAL

modified Approach-Avoidance Task (mAAT), which aims to modify automatic approach bias

Participants will undergo a baseline assessment before completing computerized tasks. During the baseline assessment, participants will be asked questions about alcohol and cannabis use. We will also ask questions about the way participants think about things, past life experiences related to substance use, and questions about how participants feel about reducing their substance use. Then, participants will complete a series computerized tasks where they will push and pull a joystick in response to images that are presented on a screen or where they will try to get a high score. During the computerized tasks, we will also be measuring brain activity using EEG. During the study, participants will also be asked to respond to questions about their health and behavior using an app on a smartphone or tablet using a secure program. Participants in the Treatment Group will then complete four sessions of the modified Approach-Avoidance Task (mAAT), which aims to modify automatic approach bias.

BEHAVIORAL

modified Approach-Avoidance Task (mAAT) that does not aim to modify automatic approach bias.

Participants will undergo a baseline assessment before completing computerized tasks. During the baseline assessment, participants will be asked questions about alcohol and cannabis use. We will also ask questions about the way participants think about things, past life experiences related to substance use, and questions about how participants feel about reducing their substance use. Then, participants will complete a series computerized tasks where they will push and pull a joystick in response to images that are presented on a screen or where they will try to get a high score. During the computerized tasks, we will also be measuring brain activity using EEG. During the study, participants will also be asked to respond to questions about their health and behavior using an app on a smartphone or tablet using a secure program. Participants in the Control Group will then complete four sessions of an Approach-Avoidance Task (mAAT) that does not aim to modify automatic approach bias.

Change in cannabis use as assessed by Timeline Followback

Time frame: Baseline and Three-Month Follow-up

The TLFB is a calendar-assisted semi-structured interview that will be used to assess cannabis and alcohol use since the last assessment. The TLFB will assess the number of days a person used cannabis over the past 90 days compared to the 90 days prior to enrolling in this study.

Change in alcohol use as assessed by Timeline Followback

Time frame: Baseline and Three-Month Follow-up

The TLFB is a calendar-assisted semi-structured interview that will be used to assess cannabis and alcohol use since the last assessment. The TLFB will assess the number of days a person consumed alcohol over the past 90 days compared to the 90 days prior to enrolling in this study.

Change in Cannabis Approach Bias (D-Score)

Time frame: Baseline, One-Week Follow-up, and Three-Month Follow-up

D scores will be calculated for each participant at baseline, posttest, and three-month follow-up. Participants' mean reaction times (RTs) during the approach cannabis trials will be subtracted from the mean avoid cannabis trial RTs. These scores are then divided by the SD across all cannabis trials. Positive scores indicate an approach bias for cannabis stimuli.

Change Cannabis Approach Bias (D-Score)

Time frame: Baseline, One-Week Follow-up, and Three-Month Follow-up

D scores will be calculated for each participant at baseline, posttest, and three-month follow-up. Participants' mean reaction times (RTs) during the approach alcohol trials will be subtracted from the mean avoid alcohol trial RTs. These scores are then divided by the SD across all alcohol trials. Positive scores indicate an approach bias for alcohol stimuli.

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.