Dopamine D3 Receptor Occupancy in Bipolar Depression
Stopped: Funding decision
United States0Started 2026-01-06
Plain-language summary
Bipolar disorder is a common condition that can cause significant disability and risk for suicide. Second generation antipsychotic medications can be used to treat depression in bipolar disorder, yet we do not know how they work. Here, we will use a recently approved medication, cariprazine (Vraylar), to treat participants with bipolar depression. They will have brain imaging with PET scans before and during treatment to understand how the medication may be working. Particularly, we will look at the role of the D3 dopamine receptor.
Who can participate
Age range
18 Years – 60 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Capacity to provide consent, and informed consent provided
. Diagnosis of bipolar I disorder and currently meet criteria for DSM5 major depressive episode
. Depression at enrollment of sufficient severity to score at least 16 on the first 17 items of the Hamilton Depression Rating Scale when including the atypical depression items addendum
. Age 18-60 years old
. Patients who are on antidepressant (SSRI, SNRI or bupropion) or antipsychotic medications at presentation will be included if they have failed that regimen, as defined as not achieving at least partial remission after an adequate dose of medications for at least four weeks. Fluoxetine will not be allowed due to its long half-life. Patients will be able to continue to take other mood stabilizer medications (lamotrigine, lithium, valproate, carbamazepine or oxcarbazepine) if they had not made changes to the dose of those medications within eight weeks of signing consent. Benzodiazepines and hypnotics are allowed throughout the study. If taking stimulant medications, they must be willing not to take these during the study.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
. Females of child-bearing potential must be willing to use an acceptable method of birth control throughout the study; abstinence if it does not require changes to usual behavior, birth control pill, male condom, IUD, dep- provera, norplant, male sterilization or female sterilization are acceptable.
. Participant is likely to tolerate medication washout if indicated
Exclusion criteria
. Diagnosis of any other major psychiatric disorders such as schizoaffective disorder, current psychotic depression. Any recent drug or alcohol use disorder; within 3 months before the study unless mild. Participant meets DSM5 criteria for manic episode at the time of screening, or has YMRS \> 12.
. Previous failed trial of cariprazine, defined by at least six weeks of treatment at the dose of 1.5 mg per day or more. Experienced intolerable side effects of cariprazine in the past. Taking any medications that are either contraindicated or that have clinically significant drug-drug interactions (such as strong CYP3A4 inducers) with cariprazine, unless there is a plan to stop these as part of the washout.
. History of clinical deterioration when any of the medications that the participant is taking at presentation have been discontinued in the past if they will be discontinued as part of the washout.
. First-degree family history of schizophrenia if the participant is less than 33 years old.
. Significant active physical illness, including blood dyscrasias, lymphomas, hypersplenism, endocrinopathies, renal failure, chronic obstructive lung disease, autonomic neuropathies, peripheral vascular disease, neuromuscular disorder or tardive dyskinesia. Any medical diagnoses that would be a contraindication to cariprazine treatment, including any movement disorders. Any history of a seizure disorder.
. Actively suicidal, as defined by expressive ideation with a plan and intent for suicide, or developing suicidal ideation that requires immediate medical or treatment intervention.
. Active lactation
. Electroconvulsive therapy within the past 6 months