Does Betaseron Cause Depression?
Understanding Clinical Trials
Clinical trials are designed to factor out many possible variables in order to measure the effectiveness and side effects of medications.
During a study, some people are given the actual medication, while others are given a placebo (which looks exactly like the actual medication but does not contain any of the active ingredients). Studies that use a placebo are known as "placebo-controlled" studies. Since Betaseron is given by injection, the placebo in Betaseron studies was also given by injection (although it contained no active ingredient). In most studies, the people (and sometimes the healthcare providers) are "blinded," which means that they do not know if they are taking the real medication or the placebo.
Side effects occur in people who are taking the medicine and in people who are taking a placebo. By studying both groups, it is easier to tell which side effects are definitely drug-related, which may be drug-related, and which have nothing to do with the drug. In clinical studies, up to 30 percent of people taking Betaseron reported having depression. However, a similar percentage of people taking a placebo also had depression. Because depression is common among people with multiple sclerosis, it is difficult to tell whether any given case of depression is actually related to Betaseron
(see Multiple Sclerosis and Depression for more information). However, some factors (such as the timing of the onset of depression in relationship to the medication) may suggest that Betaseron may (or may not) be causing or contributing to a particular case of depression.