Clinical trials are experiments conducted using human participants that seek to
determine the value of a potential treatment, such as a drug, dietary
supplement or exercise program. Most trials compare a treated group of
participants with a "control," or comparison, group, which receives an inert
substance ("placebo") or a sham treatment.
Many trials are divided into phases, the first
of which is usually quite small and almost always designed only to assess the
safety of the new treatment and how well it's tolerated. Phases 2 and 3 of a
trial are larger and address questions of effectiveness and dose.
The term "study" implies either a trial or a
more general research question under investigation, such as how many people
with a certain set of symptoms have a particular genetic change or how parents
cope with raising a child with a disability.
To learn more about the purposes and risks of
clinical trials, please go to www.clinicaltrials.gov.
This site, sponsored by the National Institutes of Health, contains general
information and listings of specific trials.
