Frequently asked questions

What are the different types of clinical trials?

The type of clinical trial used depends on the questions the researchers want to answer. Listed below are some of the different types:

  • Preventative—focuses on how to prevent a disease or stop a disease from coming back
  • Screening—investigates new ways for detecting diseases or conditions
  • Diagnostic—compares tests or procedures for diagnosing a disease or condition
  • Treatment—studies potentially new treatments, including medicines, procedures, and devices
  • Behavioral—examines methods of changing behavior to improve health outcomes
  • Quality of life—explores ways to improve patients’ comfort and quality of life

What if I receive a placebo?

In some clinical trials, you may receive a placebo. A placebo looks like and is taken the same way as the study treatment that is being tested, but it does not contain active ingredients.

Comparing a study in healthy volunteers with a placebo helps to determine whether the study treatment works to improve a disease or condition.

Whether you receive the study treatment or placebo, your health will be closely monitored by a team of healthcare providers. In addition, the information learned from the clinical trial may help you and others in the future.

What happens after a clinical trial ends?

Once a clinical trial ends, the researchers will carefully review the information they have collected. At that point, they will make a decision about whether a study treatment or procedure works and is safe. If it is proven safe and effective in a clinical trial, the study treatment or procedure may become a therapy option or even a standard of care.

Results from a clinical trial may be viewed at

Can I still see my doctor when I participate in a clinical trial?

Yes. You can continue to see your doctor while enrolled in a clinical trial. Your doctor will continue to monitor your overall health while you are in the clinical trial.

What if I do not want to participate in a clinical trial?

Your participation in a clinical trial is voluntary. You do not have to take part in a clinical trial, and you can leave at any time, for any reason. Talk to your doctor about your treatment options before taking part in a clinical trial.

Why do people volunteer for a clinical trial?

People take part in clinical trials for many reasons. When you participate in a clinical trial, you help doctors and researchers learn more about a study treatment, procedure, or disease. The information they learn may also help improve health care for people in the future.

Why are clinical trials necessary?

Clinical trials are designed to look at new ways to prevent, detect, and treat disease. They are necessary to learn whether a study treatment or procedure works and is safe. Without clinical trials, study treatments and procedures would not be available to patients who may need them.

Should I talk to my doctor about clinical trials?

You should discuss your treatment options with your doctor before deciding to take part in a clinical trial. It’s important that all your doctors know that you are taking part in clinical trial so they can be sure the protocol does not conflict with your other medicines or treatments.

Who sponsors a clinical trial?

Clinical trials can be sponsored or funded by a variety of organizations or individual including healthcare providers, medical institutions, foundations, voluntary groups, and pharmaceutical companies. They may also be sponsored by government health agencies.

Learn More

You can learn more about pulmonary hypertension and taking part in a clinical trial from the links below:


NIH Clinical Research Trials and You