The physical dangers associated with the medications are usually monitored well. However, the drug company cannot truly guarantee the actual safety of a medication until several thousand people have taken it for a considerable period. It is only the acute and common hazards of a drug which show up during early clinical testing. Although such unforeseen side effects can be quite dangerous, they are, thankfully, rare. The clinical staff, verbally and via the written consent form, must clearly notify the potential participant that the earlier the phase, the greater the risk.
Psychiatric research has an additional risk.
During the trial the volunteer's condition may markedly worsen. As this occurs, his ability to act in his own best interest diminishes. Consequently it is essential that the welfare of the study participant always be the primary concern. There must be predetermined criteria for stopping the experiment if the patient's condition deteriorates. The general practice is to define significant worsening in terms of the scores of the standardized tests which are usually administered by the research staff.