D3 Study

Did you know that many older adults with depression usually also have poor motivation, difficulty making decisions, and feel slowed down, making it hard to get around? These are important symptoms we see with depression that do not always respond well to current antidepressant medications.


But, these symptoms may be caused by a common problem: dopamine! Dopamine is a chemical messenger released by nerve cells that plays an important role in motivation, decision making, and motor function, such as how fast we move and how well we can get around. Brain dopamine decreases as we age, but not much is known about the role dopamine plays in older adults with depression.

There are currently approved medications that affect dopamine, but they are not well studied in depression. A few antidepressant medicines affect dopamine, but not the majority of them.

The purpose of this study is:

  1. To see whether dopamine function is related to depressive behaviors
  2. To determine whether depressive symptoms improve with medications that increase dopamine

This study will help determine if medications that affect dopamine should be further studied for depression. It will also help determine who may be more likely to benefit from dopamine medications.

We are seeking adults age 60 or older who either:
  • Are currently depressed and also feel like they are thinking or moving slowly


  • Have never been depressed, and are willing to serve as a comparison subject


For those individuals who are depressed, this study includes an investigational medication that affects dopamine. We want to determine if the medicine can improve depressive symptoms and slowness in thinking or walking performance.

For those without a history of depression, you will not be asked to take the investigational medication. Since you have no lifetime history of depression, we will gather information from you to compare with people who are currently depressed.


You may be eligible to participate if you are depressed and:


If you have no lifetime history of depression, you may be eligible to participate if you:

  • Are 60 years or older
  • Do not have a history of alcohol dependence or substance abuse in the last 12 months
  • Are able to have an MRI scan
  • Are able to have a PET scan
  • Are currently experiencing symptoms of depression
  • Feel like you are thinking or moving slowly
  • Have no other mental health problems, other than depression and anxiety
  • Are 60 years of age or older
  • Do not have a history of alcohol dependence or substance abuse in the last 12 months
  • Are able to have an MRI scan
  • Are able to have a PET scan
  • Have no lifetime history of mental health problems
  • Do not have a first degree relative (parent sibling, or child) with a history of depression

Why should I consider participating?

Participants all have unique reasons for joining research studies. 

By participating in this study, you are significantly helping us understand the causes of depression. This study may also inform how we treat depression in the future. You also get to learn more about your depression.

Although we cannot guarantee that you personally will benefit from participating, we try to make sure that all participants have a better understanding of their depression and a plan to help them recover.

We are dedicated and passionate about our research and could not do it without your help!

What is involved in the study?

 Interested? Great! First you will have a preliminary telephone call or survey to make sure you are eligible. If you appear eligible and agree to participate, you will complete an initial screening visit to see if you qualify for the study. 

The screening visit takes about 2.5-3 hours and will take place at Vanderbilt University Medical Center. This visit includes an interview and a physical assessment. For currently, depressed participants, this will also include a walking test and a response speed test.

A telemedicine/video screening visit may be available. Please use the contact information if you are interested in learning more about this option.

After you complete the screening process, you will then enter a baseline period. This baseline period will last up to 4 weeks and will include 2-4 in-person visits. The total time required to complete the baseline period is about 11.5 hours spread over the multiple visits. During the baseline period, you will complete one blood draw, one Magnetic Resonance Imaging (MRI) brain scan, one Positron Emission Technology (PET) brain scan, questionnaires, memory tests, and walking tests.

If you have no lifetime history of depression, your participation will end after the baseline period.

If you are currently depressed, you will then enter the treatment portion of the study. This part of the study lasts 8-10 weeks. During this period, you will take the study medication and have at least weekly contacts to assess for any problems. After starting the study medication, you will also complete an additional MRI brain scan and repeat the memory and walking tests.

Will I be reimbursed or compensated?

 Yes! Participants will receive monetary compensation for their time and efforts.


Frequently Asked Questions
  • How long is the study?  

    The length of your participation in the study will vary. The screening visit will be completed within about 4 weeks from the beginning of the baseline period. All baseline procedures will be completed within 4 weeks of entering the baseline period.

    Will I receive results from my study?   We will notify you if there are any clinically important findings.

    If I am experiencing symptoms of depression, do I have to already be diagnosed with depression to participate?   No! You do not need to be already diagnosed with depression to participate. An assessment will be done at the screening visit to determine if you are eligible for the study.

    I have a history of depression, but am not currently experiencing symptoms. Can I participate?   Unfortunately, no. However, we may have other studies you could be eligible for. In this study, we are only enrolling people who are currently experiencing depression (or have no lifetime history of depression). If you have a history of depression but are currently doing well and not depressed, this may not be a good study for you. Please see the other studies listed on our website or click here to go to our contact information. We are happy to discuss our other studies that are currently recruiting with you.



    What if I have other mental health problems?  

    People with anxiety are potentially eligible.

    Individuals with a history of Bipolar Disorder, Post-Traumatic Stress Disorder (PTSD), Obsessive Compulsive Disorder (OCD), and Schizophrenia are not eligible at this time.

    What if I am already taking a medication for the treatment of depression?  

    If you are eligible for the study and decide to participate, then you will have to stop taking your current medication. However, you will do so under the care and guidance of a study doctor. Do not fear - before you stop any medication, we will make sure you are eligible for the study.

    If you do not want to stop taking your current antidepressant, we may have other studies you could be eligible for. Please see the other studies listed on our website or click here to go to our contact information. We are happy to discuss our other studies that are currently recruiting with you.

    What if I don't want to take an investigational medication?  

    All currently depressed participants will have to take an investigational medication for this study. We may have other studies you could be eligible for that don't involve investigational medications. Please see the other studies listed on our website, or click here to go to our contact information. We are happy discuss our other studies that are currently recruiting with you.

    People without a history of depression will not be asked to take an investigational medication for this study.

    Are there medical conditions that would exclude me from participating?  

    Yes. You CANNOT participate if you have a history of:

    • Major neurological disorders, such as dementia, stroke, brain tumors, seizures, Parkinson's Disease, or Multiple Sclerosis (MS).
    • Surgical implants that send electrical signals, such as pacemakers, cardio defibrillators, and spinal cord stimulators.
    • Arthritis of any lower extremity joints (like ankles, knees, and hips) that impair your mobility, symptomatic lumbar spinal disease, or history of a joint replacement or spine surgery that limits mobility. 

    There are also certain medications that are not allowed for this study. A study coordinator and/or study doctor will discuss with you all the medications you are currently taking to see if you are eligible for this study.

    What if I don't live close to Vanderbilt University Medical Center?  

    Volunteers must be able to attend study visits at VUMC. Unfortunately, travel reimbursement is not available.

    How can I volunteer?  

    If you are 60 or older, click here to contact us.

  • What does an MRI involve?   An MRI scan is performed in a large machine that is shaped like a tunnel. The machine we use for our studies is open on both ends, but closed on the top. This scan does not use x-rays. Instead, they use a strong magnet and radio waves, like an AM/FM radio, to take pictures of your body. We do not give you any drugs or injections during our MRI scan(s). During the scan(s), you will hear "hammering", clicking, or squealing noises. They are a little loud, but you will be given earplugs to reduce the noise.


    Are there any known risks of an MRI scan?  

    There are no known major risks with an MRI scan. MRIs do not use radiation.

    Before you can complete an MRI for the study, we will take a detailed medical and surgical history to assess you for MRI safety.

    However, it may be uncomfortable being in a tight space if you experience claustrophobia. Furthermore, the noises can be loud despite the ear plugs.

    You have the option to complete a "mock" MRI scan during the screening visit. It takes place in a non-operational scanner that is similar to the scanner that will be used for other studies.

    Do I have to be able to have an MRI to participate?  

    Yes. MRIs are required for this study. Currently depressed participants will complete 2 MRIs over the course of the study, while those without a history of depression will complete 1 MRI.

    Can I be sedated during the MRI scans?   No, sedation is not permitted during the MRI scan(s). We need participants to be awake so they can complete tasks in the scanner.

    I have metal implants. Are these safe for the MRI?   Many medical implants are MRI-safe. During the screening visit, we will evaluate you for any surgical implants that may exclude you from having an MRI.
  • What does a PET scan involve?  

    The PET scan for our study involves the use of a radioactive investigational drug called [18F]Fallypride. [18F]Fallypride is an investigational drug that binds to parts of your brain that process dopamine. The drug contains a very small radiotracer that can be "seen" by the PET camera. The PET camera then takes "pictures" of the chemical activity in the brain by detecting the radioactive signal of Fallypride.

    To administer the Fallypride, we will need to place an intravenous (IV) catheter in one of your veins. After the catheter is inserted, we will begin the PET scan. The drug will be administered just before the PET scan so the PET techniques can better measure the dopamine system in the brain.

    For the PET scan, we will ask you to lie on a narrow table. We will also position your head with a chin strap or a polyurethane head holder that we will mold around your head to reduce head movement during the scan. Right before each PET scan we will perform a very short (~10-15 second) computerized tomography (CT, or "CAT") scan of the brain which helps us make sure the PET scan is positioned correctly. We will then inject the radioactive substance [18F]Fallypride through the catheter in your arm.


    Are there any known risks of a PET scan?  

    During PET Imaging, you will be exposed to radiation from x-rays and radioactive materials. This research study involves exposure to radiation from administration of [18F]Fallypride. You should not be a part of this study if you routinely work around radiation.

    This radiation exposure is not necessary for your medical care and is for research purposes only. The total amount of radiation that you will receive by participating in this study is equal to your body receiving 29 months (2.4 years) of radiation from your natural surroundings. Although the radiation exposure from this imaging study is considered acceptable by current guidelines, the effect of radiation exposure is cumulative (adds up over time) over your lifetime. Therefore, you should notify the study doctor of any other research radiation exposure that you have received over the past year or plan to receive over the next year. 

    The radioactive mixture will be injected in a vein (intravenous). As with any medication or substance, allergic reactions are a possibility. 

    If you have concerns, please do not hesitate to contact us and bring them up.

    Do I have to be able to have a PET scan to participate?  

    A PET scan is required for this study. All participants will complete 1 PET scan during the baseline period.

    Can I be sedated during the PET scan?   No, sedation is not permitted during the PET scan.

    Will I have to fast for the PET scan?   No, you do not have to fast prior to the PET scan. The PET scan will occur in the afternoon. You may have a moderate lunch with no more than a single cup of coffee or tea before the PET scan.
  • The Laboratory of Affective and Cognitive Imaging is located within the Center for Cognitive Medicine at the

    Vanderbilt Psychiatric Hospital

    1601 23rd Ave South

    Nashville, TN 37212


  • If you have any additional questions or would like to find out if you may be eligible, please click here to be taken to our contact information.