Researchers are studying AL001 to understand how it reaches the brain and how its effects compare with lithium carbonate, a commonly used form of lithium. The information from this study may help researchers better understand AL001 as a potential treatment option for psychiatric and neurological disorders.

You may be eligible for this study if you meet the following criteria.

Inclusion Criteria:

• Ages 18-65
• Diagnosed with bipolar I disorder
• Able to stay overnight inpatient as part of study visits
• Able to undergo an MRI (You cannot have any MRI-incompatible objects in your body. You must also not be claustrophobic.)

Exclusion Criteria:

• Currently taking lithium
• History of substance abuse within the past 12 months

Participation includes screening, two treatment periods, a washout period, and follow-up visits:

1. Screening: You will complete a phone screening followed by an in-person screening that may include a medical and medication history, physical exam, MRI, blood and urine samples, mood questionnaires, drug and pregnancy testing, and an electrocardiogram (ECG).
2. Treatment Period 1: You will stay at the Massachusetts General Hospital Translational Clinical Research Center for 16 days. During this period, you will receive either AL001 or lithium carbonate three times a day. You will have meals provided, ECGs, mood and health questionnaires, and other study procedures.
3. MRI and blood testing: Between Days 14 and 15 of each treatment period, you will have 8 MRI scans and 29 blood draws to help researchers understand how the study drug is processed and how it reaches the brain.
4. Washout: After Treatment Period 1, you will have a 9- to 28-day washout period. During this time, the study drug will leave your body before you begin the second treatment period.
5. Treatment Period 2: You will return to MGH for another 16-day stay and receive the other study treatment—either AL001 or lithium carbonate—three times a day. The same types of MRI scans, blood draws, ECGs, questionnaires, and other study procedures will be performed.
6. Follow-up: About 7 days after the second treatment period, you will have an in-person follow-up visit that includes a physical exam, blood draw, urine sample, and questionnaires. About 4 weeks later, you will complete a final follow-up by phone.

The order in which you receive AL001 and lithium carbonate is assigned randomly. You must sign an informed consent form before any study procedures begin.

Eligible participants may receive up to $10,300 for completing the study. Compensation includes:

• Baseline: $100
• Treatment Period 1: $4,400
• Treatment Period 2: $4,400
• In-clinic follow-up: $50
• Completion bonus: $1,350

Study-related transportation to and from visits is provided at no cost. Hotel stays and meals are also covered when applicable, and participants will receive study swag.

There is no cost for you to participate in our research study.