Clinical studies play a pivotal role in arriving at new treatments for both infectious and chronic diseases. As you explore these studies, it’s important to understand common terminology used in clinical trials, so that you can make more informed decisions before enrolling in one. Here are some terms as provided by the U.S. Food and Drug Administration (FDA).*

What are some frequently used clinical trial terms?

Some commonly used clinical trial terms include:

• Adverse event (AE). An AE is “any undesirable experience associated with the use of a medicine in a patient.” AEs may be side effects from drugs or other therapies, and can range from mild to severe or even fatal. 
• Comparison. In clinical trials, comparison may be made between either the results from the drug and the results from a placebo, or the results from one drug and those from another drug. 
• Compassionate use. For patients with serious illnesses who meet certain criteria, are disqualified from trial enrollment, and have exhausted all other options, the FDA allows for the compassionate use of unproven treatments as a last resort. This is also called expanded access. 
• Double-blind, randomized, controlled clinical trial: In this study design, participants are approximately evenly split into an intervention or experimental group that receives the study treatment, and a control group that receives either no treatment or the standard treatment. Double-blind means that neither the researchers nor the participants know which group is receiving the intervention. This makes for more objective results.
• Inclusion and exclusion criteria. These are the collective factors that scientists use to determine who is and is not eligible to participate in a given research study. Depending on the focus and goal of the study, these factors may include age, personal or family health history, location, smoking status, and/or other demographic details. 
• Informed consent. Before you even begin the formal screening process to enroll in a clinical trial, you will be given an “informed consent” form to fill out and sign. Giving your informed consent means that you have learned and understood all the aspects of the study and agree to participate in the research. Participating in a clinical trial is always voluntary and participants can withdraw consent at anytime. 
• Placebo effect. A placebo is a pill with no active ingredients. Some study participants who are given a placebo still receive, or think they receive, some benefit. This can be due to feelings of hope, the belief that they received the actual medicine, a desire to please, and many other factors. This is referred to as ‘the placebo effect.’
• Pre-Clinical Data. In the U.S., before an experimental treatment can be tested in human beings, drug manufacturers and research scientists must provide proof to the FDA that the drug has already been safely and effectively tested on animals. They must also explain what protocols have been established for the human trials. 
• Standard treatment. In a clinical trial, when a control group receives the “standard treatment,” it refers to the best and most commonly used treatment available, according to the majority of medical professionals. 

*Food and Drug Administration. (2019, Apr. 19). Glossary of Terms. https://www.fda.gov/patients/clinical-trials-what-patients-need-know/glossary-terms