Glossary

Essential terms for understanding mental health clinical research

Comparison–To learn more, researchers compare results from patients in the experimental groups with results from patients in the control groups.

Confidentiality regarding participants–This refers to the practice of maintaining as private all information related to clinical trial participants, including their personal identity and all personal medical information. Results from the study will usually be presented in terms of trends or overall findings and will not mention any specific participants.

Control group–The group of participants that receives standard treatment or a placebo. The control group may also be made up of healthy volunteers. Researchers compare results from the control group with results from the experimental group to find and learn from any differences.

Double-blind research design–A study in which neither the participant nor the researcher knows whether the participant is in the treatment or control group.

Durable power of attorney–The authority to act for another person in specified or all legal or financial matters.

Double-blind, randomized, controlled clinical trial–This is a clinical trial in which the researchers evenly divide study participants into a group receiving the experimental intervention and a group receiving standard or no treatment. Neither group knows how it has been assigned. This practice reduces the chance for a “placebo effect,” in which a treatment with no active ingredient produces results expected from a treatment with an active ingredient.

Experiment–A study done to answer a question. Other words to describe an experiment are “research,” “study,” and “protocol.”

Experimental group–The group of participants in a study that receive the experimental or study intervention (such as medication or psychotherapy).

Food and Drug Administration (FDA)–The FDA is the Federal agency responsible for ensuring that foods are safe, wholesome and sanitary; human and veterinary drugs, biological products, and medical devices are safe and effective; cosmetics are safe; and electronic products that emit radiation are safe. Some of the agency’s specific responsibilities include regulating medications and devices.

Healthy volunteer–In a clinical study, a person who does not have the disorder or disease being studied. Results from healthy controls are compared to results from the group being studied.

Inclusion/exclusion criteria–Inclusion criteria are the factors that allow someone to participate in a clinical trial. Exclusion criteria are the factors that prevent someone from participating in the trial. These factors may include a person’s illness, health history, past treatment, age, sex, or where he or she lives.

Informed consent–When a participant provides informed consent, it means that he or she has learned the key facts about a research study and agrees to take part in it.   For more detailed information, see the “What is informed consent?” section in this guide.

Inpatient–A person who is hospitalized for at least one night to receive treatment or participate in a study.

National Institutes of Health (NIH)–Part of the U.S. Department of Health and Human Services, NIH is the primary Federal agency for conducting and supporting medical research. NIH scientists investigate ways to prevent disease as well as the causes, treatments, and even cures for common and rare diseases. Composed of 27 Institutes and Centers, NIH provides leadership and financial support to researchers in every state and throughout the world.

Outpatient–A person who receives treatment or participates in a study but is not hospitalized overnight.

Placebo–An inactive pill. This is sometimes called a “sugar pill.” In some studies, participants may be assigned to take a placebo rather than the study medication. Ask the researcher if this is a possibility for the study that interests you.

Placebo effect–Sometimes people taking a study medication receive benefits that are not from the chemicals in the medicine. This is called a “placebo effect.” For example, if a participant feels hopeful about a treatment, he or she may be more likely to notice positive changes than negatives ones. A researcher’s hope may also sway a participant’s response. Double-blind research design helps minimize the placebo effect.

Post-marketing studies–Studies done after a treatment, medication or device is approved for use by the FDA. These studies gather additional information about a product’s safety, effectiveness, or best use.

Protocol–A study done to answer a question. Other words to describe a protocol are “research,” “study,” and “experiment.” “Protocol” also refers to the plan that details what researchers will do during the study.

Randomization/random assignment–This is the process in which researchers evenly assign study participants into a group receiving the experimental treatment being studied, and others into a group receiving standard or no treatment. Participants are assigned to a group based on chance, not choice. You have the same chance to be placed in any of the test groups.

Research–A study done to answer a question. Scientists do research when they’re not sure what will work best to help people with an illness. Other words to describe clinical research are “clinical trial,” “protocol,” “study,” and “experiment.”

Sponsors–Clinical trials are sponsored or funded by various organizations or individuals, including physicians, foundations, medical institutions, voluntary groups, and pharmaceutical companies, as well as Federal agencies such as NIH, FDA, the Department of Defense, and the Department of Veterans Affairs.

Standard treatment–The treatment that medical professionals consider at the time of the study to be the most prevalent and best available treatment.

Standardized procedures–These are study rules that researchers must follow exactly for every participant, regardless of what each participant is used to. For example, if you normally take a medicine by injection but the experiment is testing the same medicine in pill form, the researcher must prescribe pills to you. The researcher cannot use a different method for you.

Study–Conducted by a principal investigator who is often a doctor.  Members of the research team regularly monitor the participant’s health to determine the study’s safety and effectiveness. Other words to describe a study are “clinical trial,” “protocol,” “experiment,” and “research.”

Single-blind research design–A study in which one party, either the investigator or participant, is unaware of what medication or intervention the participant is taking; also called single-masked study.

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