If you’re living with a sleep disorder, you may have thought about joining a clinical trial — a medical research study that includes human participants. In these studies, researchers test ways to treat, diagnose, or prevent sleep disorders. Learning some basic terms related to clinical trials can help you better understand how clinical trials work. This knowledge can make it easier for you to decide whether joining a clinical trial might be right for you.

Here are 10 clinical trial terms that can help you decide whether you want to participate in a trial for a sleep disorder such as idiopathic hypersomnia, narcolepsy, chronic insomnia, obstructive sleep apnea (OSA), or restless legs syndrome.

1. Clinical Trial Phases

If you’re thinking about joining a clinical trial for a sleep disorder, you’ll be part of a specific phase of the study. Clinical trials happen in stages called phases. Each phase helps researchers learn different things about the treatment.

Phase 1

A small group of people take the treatment so researchers can check if it’s safe and find a good dose range. The treatment option studied could be a drug, a device (like a continuous positive airway pressure machine, or CPAP), a behavioral intervention (such as cognitive behavioral therapy, or CBT), or a mix of these. For drugs, researchers want to find a dose that is both effective and safe to take.

Phase 2

A larger group of people joins this phase. The goal is to see how well the treatment works and to figure out the most effective dose for different conditions. Usually, one group of people gets the real treatment and another group gets a placebo (inactive treatment). Researchers compare the two groups to see if the treatment is more effective than the placebo.

Joining a clinical trial is always voluntary. You can leave the study at any time, for any reason.

Phase 3

An even larger group of participants takes part in this phase, often over a longer period than in phase 2. Some people may receive a placebo or the current standard treatment. After a phase 3 trial, the U.S. Food and Drug Administration (FDA) usually decides whether the new drug or device should be approved for public use.

Phase 4

This phase happens after a treatment is approved by the FDA, and researchers sometimes continue to study it. They’ll keep reviewing outcomes, side effects, and other data from people in the general public who are using the new treatment.

2. Clinical Trial Eligibility

Not everyone with a sleep disturbance or sleep disorder can join a clinical trial. Each trial has specific rules, or eligibility criteria, based on what the researchers are studying.

Researchers use a screening process to figure out who qualifies for a trial. For example, some studies may only accept people of a certain age, such as older adults or children, who have a particular type of sleep disorder. Or a study may look for participants with certain symptoms, like excessive daytime sleepiness. A clinical trial may also consider factors such as your current treatment, other medical conditions, and your medical history.

3. Informed Consent

If you qualify to join a clinical trial for a sleep disorder such as narcolepsy or idiopathic hypersomnia, the research team will explain what the study is about and how it will be conducted. This process is called informed consent.

You’ll have the chance to ask questions and talk to the researchers who are running the study. You’ll also be given time to talk to your primary healthcare provider, sleep specialist, neurologist, or loved ones before you decide.

An institutional review board is a group of independent experts who make sure everyone participating in a study remains safe.

If you decide to take part in the study, you’ll be asked to sign an informed consent form. This shows that you understand the study and agree to participate.

Joining a clinical trial is always voluntary. You can leave the study at any time, for any reason.

4. Institutional Review Board

An institutional review board, or IRB, is a group of independent experts who oversee clinical research projects involving people. The board’s job is to make sure everyone who participates in a study remains safe. The IRB, also called an independent ethics committee, protects participants’ rights and well-being.

IRBs also make sure that the trial is being done properly and follows all the required rules.

5. Study Investigator

Every clinical trial has one or more investigators who are responsible for running the study. They help make sure the study is done properly and safely. A study investigator, or clinical investigator, is often a medical professional, like a doctor or nurse or another type of medical science expert. They design the study plans, collect and review data, and report the study’s findings. The lead person in charge is usually referred to as the principal investigator.

6. Investigational Drug or Device

If you’re thinking about joining a clinical trial for a new treatment or a new use for an existing treatment, the study investigators might talk about an investigational drug. This refers to the medication or treatment being tested in the study.

An investigational drug is a drug that hasn’t yet been approved by agencies like the FDA, but it has been studied extensively in laboratories and reviewed by an ethics committee to make sure it’s safe to test on humans.

Investigational treatments in sleep disorder studies can include sleep disorder drugs, medical devices, or behavioral interventions.

7. Placebo

In some clinical trials, not all participants receive the investigational drug. Instead, some people may get a placebo, which looks like the treatment but doesn’t have any active ingredients. This helps the investigators see if the real treatment works better than no treatment at all (the placebo).

In some cases, instead of a placebo, participants may continue taking an existing or standard treatment for a sleep disorder so researchers can compare the new treatment to the one already in use.

8. Control Group

The group of participants who aren’t given the investigational treatment is known as the control group. They may receive a placebo or continue using a standard treatment.

Researchers compare the results of the control group with those of the group receiving the investigational treatment. This helps them understand how effective the new treatment really is.

9. Randomization

Study investigators often use a process called randomization to decide who will be in the treatment group and who will be in the control group. This means participants are randomly assigned to each group, like flipping a coin. Randomization helps ensure that the groups are as similar as possible.

10. Single Blind or Double Blind

In a single-blind study study, participants don’t know whether they’re part of the control group or the investigational treatment group for the clinical trial.

In a double-blind study, neither the participants nor the clinical trial staff know who is in which group. This process is also called masking. Like randomization, masking helps prevent bias. It allows researchers to study how well a treatment works as objectively as possible.

Talk With Others Who Understand

MyNarcolepsyTeam is the social network for people with narcolepsy and their loved ones. On MyNarcolepsyTeam, more than 11,000 members come together to ask questions, give advice, and share their stories with others who understand life with narcolepsy.

Have you participated in a clinical trial? What tips do you have for people who are interested in clinical trials? Share your experience in the comments below or on your Activities page.