Who Participates in a Clinical Trial?

The plan for every clinical trial has specific “inclusion” and “exclusion” criteria that specify who can and cannot participate in the study. Some clinical trials include only men, only women, or only a particular age volunteer.

Some studies require healthy volunteers while others use only volunteers with a particular medical condition. The types of volunteers needed are different for every clinical trial.

Healthy volunteers have an important role in many clinical trials, because they allow researchers to define “normal” for a new treatment or drug. Their responses to treatment are compared to the responses of patients receiving the same treatment. This helps researchers understand how the treatment affects the disease.

Patient volunteers with known medical problems may participate in clinical trials to help researchers learn better ways to diagnose, treat, or cure their medical conditions.