Preliminary Efficacy Trial of a Digital Intervention for Depression and Cannabis Use

BEHAVIORAL

Amplification of Positivity - Cannabis Use (AMP-C)

AMP-C is a smartphone-based digital intervention that includes activities that focus on positivity (e.g., noticing and capitalizing on positive events) to increase positive emotions, thoughts, and behaviors. The role and impact of CU on the maintenance of depression and reward dysfunction (and vice versa), is intertwined throughout the intervention.

Change in Depressive Symptoms (Patient Health Questionnaire-9; PHQ-9)

Time frame: Baseline, Primary Endpoint: Post-Intervention (approximately one week after completing intervention), Secondary Endpoints: Intervention Midpoint (4 weeks into intervention), 1-, 3-, 6-, and 12-months after completing intervention

Depressive symptoms will be measured with the Patient Health Questionnaire-9 (PHQ-9). The PHQ-9 is a widely-used 9-item self-report measure that assesses depressive symptom severity over the previous two weeks. Scores on the PHQ-9 range from 0-27, with greater scores indicating greater depression severity.

Change in Cannabis Use Frequency (Daily Sessions, Frequency, Age of Onset, and Quantity of Cannabis Use Inventory; DFAQ-CU)

Time frame: Baseline, Primary Endpoint: Post-Intervention (approximately one week after completing intervention), Secondary Endpoints: Intervention Midpoint (4 weeks into intervention), 1-, 3-, 6-, and 12-months after completing intervention

Cannabis use use will be measured with the Daily Sessions, Frequency, Age of Onset, and Quantity of Cannabis Use Inventory (DFAQ-CU). The DFAQ-CU is a 24-item self-report measure that assesses frequency, age of onset, and quantity of cannabis use. There are six factors: daily sessions, frequency, age of onset, marijuana quantity, concentrate quantity, and edible quantity. The six factors, except age of onset, are independently scored, and higher scores indicate greater cannabis use. Our primary outcome will assess changes in frequency.

Usability (System Usability Scale; SUS)

Time frame: Post-Intervention (approximately one week after completing intervention)

The System Usability Scale (SUS) is a 10-item self-report measure commonly used to assess the degree to which participants endorse ease of use following task-based operation of computer systems (i.e., perceived usability). Total scores on the SUS range from 0 to 100, with greater scores indicating greater usability. An average score of 68 or greater on the SUS in our AMP-C group will indicate acceptable usability.

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.