Taking part in research is entirely voluntary; something you can choose to do if you want to. For this reason it is very important that you are aware of any risks or benefits involved so that you are able to make this decision.
Researchers are not allowed to persuade you to take part in research, they should not promise you health benefits which they can't guarantee. They might believe that a new treatment they are testing will be better than the existing treatment, but they can only tell you that you may benefit.
The biggest benefit of medical research is often not directly to you, but is the increase in medical knowledge which benefits future patients. If you are currently receiving treatment it is likely that you are benefiting from research which has been carried out on patients in the past.
Weighing up risks and benefits also depends on you as an individual. If you hate needles you will not feel much benefit from taking part in a study which involves having a number of extra blood tests.
While you are on a study, your general health may be monitored closely by the researchers. This may seem like an advantage to one person who finds the extra monitoring reassuring, whereas another person could see this as a disadvantage because they find going to hospital stressful.
Every research study is different. Some may involve simply filling in a questionnaire or being interviewed. In this case there is no added risk to your health from taking part. In some other studies doctors may observe your reaction to treatment which you are already taking. In this type of study there is no risk from having a new treatment, but it is possible that you may have to be monitored more closely than usual which might involve additional tests.
Clinical trials are studies where new treatments and medicines are tested and these involve most risks to patients. This doesn't mean they are dangerous as they have to be carried out under very strict rules which maximise safety. The risk to you is mainly that you are choosing to have a treatment or medicine which you wouldn't otherwise be taking. This treatment could turn out to be very beneficial to you, but there is always a chance that it could cause side effects or not work as well as another treatment.
Any medical treatment carries at least a small element of risk, even taking an aspirin if you have a headache. The reason that researchers have to emphasise risks is because research is voluntary and it would be wrong if you volunteered without being clearly aware of the possibility, however small, that things could go wrong.
For this reason take time to consider your feelings about any risks and benefits of taking part in the study before agreeing to go ahead.
If you are harmed or injured as a result of taking part in a research you may be entitled to compensation. If the study is sponsored by a pharmaceutical company, the company will have an agreement to compensate research subjects who are harmed because of a drug or treatment involved in their study.
If you are harmed due to someone's negligence (meaning someone is to blame for the harm) while taking part in research, then you have the right in law to claim compensation for your injuries. However, you should be aware that you may have to pay for any legal action.