This study is enrolling emerging adults (ages 18-25) with cannabis use disorder (CUD) to examine sex differences in (a) cannabis withdrawal symptoms during short-term cannabis abstinence, (b) cannabidiol (CBD) versus placebo effects on stress reactivity during short-term cannabis abstinence, and (c) the relationship between stress reactivity and time to cannabis relapse after short-term cannabis abstinence. The proposed study is designed to reveal sex differences and guide the development of tailored treatments that address factors disproportionately affecting emerging adult females with CUD.

Participants will complete an assessment visit to determine eligibility. Eligible participants will be scheduled for their next visit and will be instructed to abstain from cannabis use for 3 days. Participants will be set up with a phone application (app) and given instructions on its use. This app will send twice daily, random surveys everyday throughout study participation with questions about cannabis use, cravings, and overall mood. Participants will also complete twice daily saliva samples.

At the end of the 3 days, participants will return to the clinic for their second visit. Participants will complete a urine and blood sample at each visit. After eating a snack, participants will receive one dose of CBD (800mg) or placebo and then participate in a stress task. Upon completion of the stress task, participants will complete 3 saliva samples and then be discharged after evaluation by research staff. After the completion of Visit 2, participants will continue to complete twice daily surveys for 10 days. The study will last approximately 14 days.

There are risks involved with participating in this study, including risks associated with CBD, risks associated with the stress task and study procedures, emotional distress from answering personal questions, and loss of confidentiality. There is a risk of experiencing cannabis withdrawal symptoms during the 3-day period of cannabis abstinence. Some potential risks related to CBD include dry mouth, diarrhea, reduced appetite, drowsiness, and fatigue. There is a risk of loss of confidentiality, but the researchers will code the samples and research information to protect privacy. There are no direct benefits to the participant, but we hope the knowledge gained will help us inform future clinical strategies to address cannabis use in emerging adults.

Alcohol misuse is a risk factor for early onset cognitive impairment, contributing to 10% of early onset dementia, with risk corresponding to consumption. Additionally, continued drinking risks worsening cognitive decline and dementia progression, while worsening cognitive impairment contributes to drinking escalation. Repetitive transcranial magnetic stimulation (rTMS) has been shown to improve cognition in Alzheimer's Disease and Related Dimentias (ADRD) and separately reduce heavy drinking in alcohol use disorder. Our objective is to optimize rTMS for simultaneous mitigation of both drinking and cognitive dysfunction in older adults.