Thinking of joining a clinical trial?

 What is a clinical trial?

A clinical trial is a research study that is designed to answer health questions. This research study is performed on human volunteers who consent to participating. This article explains some basics of clinical trials and discusses some of the pros and cons of participating in a trial.

There are many types of clinical trials:

  • Treatment trials, which test possible new treatments, including medications
  • Prevention trials, which test approaches that will prevent a disease from happening or returning
  • Diagnostic trials, which test possible new ways to diagnose a disease or medical condition
  • Screening trials, which test new methods of learning whether you have a medical condition
  • “Quality of Life” or supportive trials, which test how life can be improved for people with illnesses

There are several phases of clinical trials:

  • Phase 1 takes place early in the development of a new treatment or medication. A small number of people are in the trial to learn if dosages are safe and to examine side effects.
  • Phase II refers to when the treatment or medication is given to people to see if it is both safe and effective
  • Phase III applies to when even more people are given the treatment or medication to learn if it is effective, see how it compares to other treatments, and learn what side effects occur
  • Phase IV studies occur after the medication or treatment is marketed. These studies focus on the best use for the medication or treatment, the side effects, and the benefits

What is it like to be in a clinical trial?

Because clinical trials usually test new treatments or procedures, there are often strict rules, and all participants are volunteers who consent to participating. Only certain people may be eligible. Some studies require healthy volunteers, and others need volunteers with specific medical conditions. Your medical history and current treatments may allow you to participate, or exclude your participation in the trial.

Before you can begin, you must sign an informed consent form. This form tells you everything you need to know about the trial so you can decide if you want to participate, including:

  • What the research question is that the trial hopes to answer
  • Who is eligible for the trial
  • The names of the people responsible for the trial
  • What you will do if you participate
  • How long the trial will last
  • Possible risks of participating
  • What the benefits of the new treatment might be
  • What costs you might face
  • If there is payment for participation in the trial
  • What circumstances might end your participation in the trial
  • Your rights as a participant


What is a clinical trial protocol?

Researchers follow strict study procedures during the trial, written in a document called the study protocol. The study may divide participants into two or more groups, and each group receives a different treatment. Assignment to a group is usually a random process (like tossing a coin) and participants may not know to which group they are assigned. The control group does not receive the medication or procedure being tested, but receives another medication or procedure, or a placebo. A placebo is a treatment that is not expected to have an effect, often a harmless substance that has no effect. The experimental group does receive the medication or procedure being tested.

Your own healthcare provider cannot change your group assignment. Your progress will be closely monitored in the study.

What are the pros of participating in a clinical trial?

You may want to participate in a clinical trial:

  • To gain access to a new medication or procedure
  • To have your health monitored closely
  • To potentially benefit others with your disease or condition
  • To be one of the first to experience a new procedure or treatment


What are the cons of participating in a clinical trial?

  • You may not be able to choose whether you receive the new treatment
  • New medications and procedures may cause side-effects that may worsen your present situation
  • Not all side-effects or results are known and life-threatening conditions or side-effects can occur
  • The trial may require an increase in the number of your medical visits
  • The medications or procedure may not continue to be available to you after the trial
  • Some health plans do not cover all of the costs of clinical trials

Whether to participate in a clinical trial is a personal decision that you should discuss thoroughly with your healthcare provider. It is important to know as much as you can about your specific condition and the details of the trial, before you decide to join the trial. Your healthcare provider can help you weigh the risks and benefits and assist you in deciding whether a clinical trial is right for you.


National Institutes of Health (2007). Understanding clinical trials. Retrieved June 19, 2008 from