This is why i never take a prescription that has been on the market for less than 5 years. In fact, all of the drugs i take right now (nicotine included) have been on the market in some form for at least 20 years. Due to the accumulation of data, i know exactly what i'm taking.
Remember that big scare about how the newer antidepressants can make kids suicidal? They knew that before they released it. Here is what i remember about their process of testing them; this is all of the top of my head btw, hence the lack of detail. I no longer have the links but this information is not too hard to find:
1) The company gathers depressed patients for the trial and groups them into a control (placebo) and an experimental (drug) group. Lets say there are 100 people in the experimental group for convenience's sake.
2) Fast forward a couple steps... they find that about 1/3 of the exp. group shows improvement in their symptoms, about 1/3 shows no change and the rest experience a worsening of their depression, with some now experiencing suicidal symptoms. For convenience's sake, we'll say that in this trial, 30 people are now more severely depressed.
3) The company decides that the risk of self-harm by these 30 individuals overrides their need to finish the trial. These 30 individuals are dropped from the study weeks before it is finished, for the sake of their health. This leaves 70 people to finish the trial.
4) Fast forward a few steps... now a report of the study is presented to the FDA. This reports indicates that there were 100 people included at the beginning of the trial and 70 finished (it is not unusual for many people to not finish a study, especially if it lasts a few months). As per protocol, only the results of the 70 people who were in the trial from start to finish are included in the report; the results from the 30 who dropped are not included because they did not finish the trial and, hence, are not representative of it.
In the end, all the FDA sees are the 70 people who did ok; the 30 who did not fare well are only mentioned and their (suicidal) side effects are never reported to the FDA. This is all perfectly legal.