What is a clinical trial?
Who can participate in a clinical trial?
How does a clinical trial work?
What questions should be asked before choosing to participate?
What is informed consent?
What are the benefits and risks of participating in a trial?
What are some of the major central nervous system disorders studied in clinical trials?



A mental illness that usually strikes in late adolescence or early adulthood, but can strike at any time of life. The signs and symptoms vary, but all people with the disorder show one or more symptoms such as delusions, hallucinations, bizarre or inappropriate behavior, disorganized speech, and “negative symptoms” such as lack of motivation or interest, diminished cognitive functioning and decreased emotional expression.

In addition, people with schizophrenia suffer a decline in the level of functioning in the world—for example, not being able to work at the level of skill or concentration at a job they held before becoming ill. They may show a decline in the ability to attend to household chores, the demands of raising children, or maintaining a social life.

Schizophrenia may be chronic, with the individual constantly experiencing hallucinations or other symptoms. Or the individual may be symptom-free for a period of time, only to experience more acute psychosis at other times.

Bipolar Disorder

Also known as manic-depressive illness, bipolar disorder causes unusual shifts in mood, energy, activity levels, and the ability to carry out day-to-day tasks. Unlike the normal ups and downs most people experience, bipolar disorder symptoms are severe and can result in damaged relationships, poor job or school performance, even suicide. Bipolar disorder can be treated, however, and the people it affects can lead full and productive lives.

Not easy to spot at first, the symptoms of bipolar disorder may seem like separate problems rather than as parts of a larger one, and some people can suffer for years before proper diagnosis and treatment. It is a disorder that must be carefully managed throughout a person’s life.

The symptoms of bipolar disorder are intense emotional states occurring in distinct periods called “mood episodes,” from overly joyful or overexcited “manic” states to extremely sad or hopeless “depressive” episodes. Sometimes, a mood episode includes symptoms of both mania and depression, and is referred to as a mixed state.

Alzheimer’s Disease

Named for German physician Alois Alzheimer, who first described it in 1906, Alzheimer’s disease is a progressive and fatal brain disease affecting as many as 5.3 million Americans. Alzheimer’s destroys brain cells, causing memory loss, problems with thinking, and behavior severe enough to affect work, lifelong hobbies or social life. The disease gets worse over time and is always fatal.

Alzheimer’s is the most common form of dementia—a general term for memory loss and other intellectual abilities serious enough to interfere with daily life—and accounts for 50 to 80 percent of dementia cases.

Currently, Alzheimer’s disease has no cure, but treatments for symptoms, combined with the right services and support, can make life better for the millions of Americans living with Alzheimer’s. In addition, an accelerating worldwide effort is under way to find better ways to treat the disease, delay its onset, or prevent it from developing.