What It’s Like to Be a Patient in an NIH Clinical Trial

Interview with Alexandra Ambrico

Alexandra Ambrico

Alexandra Ambrico

Alexandra Ambrico is a “healthy volunteer” participating in the NIH clinical trial ”Brain Dopamine Function in Human Obesity,” which is measuring dopamine activity in the brain to determine how it relates to body weight and eating behavior. Here she answers a few questions about what it’s like to be part of the trial. Her responses have been lightly edited.


About the Brain Dopamine Function in Human Obesity Clinical Trial

Being conducted by Senior Investigator Kevin Hall, chief of the Integrative Physiology Section, Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, and Valerie Darcey, a postdoc in his lab.

Hall’s lab investigates how metabolism and the brain adapt in response to a variety of interventions in diet and physical activity. This study is a follow-up to an earlier one that explored how dopamine in the brain influences eating behavior in people with obesity (Mol Psychiatry 19:1078–1084, 2014). That study found that opportunistic eating behavior and body mass index (BMI) were both positively associated with dopamine D2-like receptor-binding potential (D2BP) in the brain’s dorsal and lateral striatum, whereas BMI was negatively associated with D2BP in the ventromedial striatum. These results suggested that people with obesity have alterations in dopamine neurocircuitry that may increase their susceptibility to opportunistic overeating while at the same time making food intake less rewarding, less goal directed, and more habitual.

The objective of the current trial is to better understand how brain function, particularly dopamine activity, relates to body weight and eating behavior. Participants must have a BMI of at least 18.5 kg/m2 (normal BMI is between 18.5 kg/m2 and 25 kg/m2), be between 18 and 45 years old, be relatively healthy, and meet certain other eligibility criteria. During the trial, their activities include undergoing magnetic resonance imaging (MRI) and positron emission tomography (PET) scans to measure dopamine; having fasting blood and urine tests; eating a special diet five days before an inpatient visit; staying at the Clinical Center for five days as an inpatient; wearing a monitor that measures glucose; having X-rays taken to measure body fat; and, for 12 months after the visit, tracking their weight and physical activity using a special scale and activity monitor. Hall expects to recruit 60 participants with and without obesity for the study.


How did you find out about the clinical trial?

I came across the trial on Twitter last year. I have been following the NIH Clinical Center on Twitter for years and was excited about participating in trials as a healthy volunteer now that I live near NIH. Due to COVID-19 restrictions, I was not able to participate in the study until May 2021. However, I stayed in touch with the researchers on the study to be notified when the trial resumed.

What was your understanding of what the trial was about?

I understood that “Brain Dopamine Function in Human Obesity” trial was designed to understand aspects of brain function and how it relates to body weight and weight change by studying the effects of dopamine activity. I was informed that the researchers would use PET and MRI scans and different radiotracers to measure dopamine activity in regions of the brain involved in reward processing and feeding behavior. How much dopamine is released may affect these processes and behaviors. The researchers would also track my weight and physical activity throughout the year following my inpatient visit, as well as my body composition and brain structure at a one-year follow-up visit. These results would help them understand how brain dopamine may relate to future changes.

What concerns, if any, did you have before entering the trial?

I truly did not have any concerns going into the trial because all of my questions were answered. I was able to work remotely throughout my inpatient stay and organize my day since I was given the schedule in advance. During the outpatient portion (the five days before my inpatient visit), I was able to pick up my meals early in the morning so as to not conflict with my work schedule.

What were your biggest motivators for participating?

My biggest motivation for participating in this trial was to give back to science. I am always looking for ways to volunteer. When I saw the posting on Twitter, I was excited to participate in a clinical trial at NIH. Having a background in science, especially research—and knowing what it takes to write a protocol and outline a study—provided a perspective that I wished to share. I was very motivated to be able to share my story with colleagues and friends, in the hopes that they too would participate in more trials and give back to science. It is so important to have healthy volunteers. We see that now especially with the COVID-19 pandemic. It’s incredible that a year later, we have access to vaccines. That would not be possible without clinical trials. Lastly, paramount to my decision was the opportunity to give back to the biomedical enterprise at a time when Americans are internalizing the importance of research. Taking part in a trial at the center of our nation’s preeminent biomedical research institution was truly my honor as a scientist and a citizen.

Can you briefly describe what you had to do for the trial?

I had a blood draw, electrocardiogram, and physical. I also met with a nutritionist prior to the start of the trial to establish a baseline and create the meal plan. During the first outpatient portion of the trial, I was put on a five-day diet-stabilization meal plan with meals prepared by NIH’s metabolic kitchen. I could not drink or consume anything else during this time. Following the outpatient study, I then checked into the NIH Clinical Center for a five-day inpatient stay. I was given activity-monitoring devices to wear on my ankle, wrist, and waist during my inpatient stay and for two weeks afterwards. During my inpatient stay, I had blood draws, continuous glucose monitoring, body composition analysis, MRIs, PET scans, iPad questionnaires and computer tasks, the diet-stabilization meal plan, and my vitals were taken daily. I could not exercise during the study.

How was your regular routine affected by the trial and how did you adapt?

Not being able to exercise was more difficult than I expected. Living in Washington, D.C., my main method of transportation is walking. I also do an exercise class online every day. I was grateful this restriction was only for a few days. I thought it would be hard to stick to the diet, however, I did not have any urge to eat any foods that weren’t part of the study. I found it harder to eat all of the food provided, especially during my inpatient stay. I don’t usually eat large meals in one sitting; I normally eat smaller amounts throughout the day.

How was the food?

I quite enjoyed most of the food. I worked with a nutritionist, who allowed me to share my likes and dislikes and choose the outpatient and inpatient menu. This ensured that I would eat all of the meals provided. Overall, I was satisfied with the selection.

Was there anything surprising or unexpected that happened?

During the end of the trial, I experienced some stomach issues. I later found out that I had higher sensitivity to certain foods that I was consuming throughout the study. The doctors and nurses were monitoring me closely and made sure I felt okay. I cannot stress enough how incredible the staff was at the NIH Clinical Center. They provided me their contact details and told me to reach out if I had any questions or concerns. Even though I was alone (as an inpatient) and could not have visitors, I did not feel the least bit lonely. I had the pleasure of having many conversations with the nurses throughout my inpatient visit and they were there for me the entire time.

How long will you continue to participate in the trial?

I will participate in the trial for one more year. I will wear an activity monitor and weigh myself daily on the scale provided. I do not have to adjust my daily routine. I can go back to my normal level of exercise and can eat my usual foods.

Is there anything important that you think others considering (or who are on the fence about) participating in a clinical trial should know?

I would say the most important thing to do is ask questions and get to know the researchers on the study. I felt comfortable asking questions and relaying how I felt, which made me feel at ease.

What other clinical trials have you taken part in?

Unfortunately, I had COVID-19 last year. Because of this, I wanted to find a way to participate in the ongoing effort to get the pandemic under control. I signed up for studies and trials—including questionnaires and blood draws—that were open to people who had had COVID-19. I felt like I was doing my part and giving back to science.

What advice do you have for researchers looking to recruit trial participants?

I think it is important to target different demographics. I found out about my study on Twitter, but perhaps TikTok would be a great way to target the younger generation since there are over a billion users on the platform. With short, one-minute videos, researchers could share the basics of a trial and encourage the public to participate. This strategy could be just as important for recruiting healthy volunteers as it is for finding those looking for experimental treatments and trials. I also think it would be great to have posters or flyers with the clincialtrials.gov link and maybe a QR code that would link to closed-caption videos where people would learn more about how to get involved. Providing an open line of communication is the most important thing for researchers to keep in mind while talking to participants. I was in constant contact with the nurses and patient coordinators throughout the study and they answered all of my questions. I think this type of communication is equally important during recruitment.


Alexandra Ambrico is the Administrative and Special Projects Manager at the International Biomedical Research Alliance, a nonprofit that was created in 2005 to support the NIH Oxford-Cambridge Scholars Program and associated global Ph.D. and M.D./Ph.D. training programs based in NIH’s intramural research program. Before joining the Alliance, she worked as a research technician at Cold Spring Harbor Laboratory (CSHL, Cold Spring Harbor, New York); coauthored four papers in Science, Cell Reports, and Journal of Cell Biology; and used her mouse-modeling skills to understand cancer metastasis and dormancy, specifically in prostate and lung cancer. She also cofounded CSHL Women in Science and Engineering and led an outreach and education team to create events for young girls and underrepresented minorities in science, technology, engineering, and mathematics. Outside of work, she is an avid reader, traveler, and foodie.