There is a black box warning on anti-depressants for kids. It seems to me that the increased risk for suicide has been known for a while. This is why it is important to monitor a person's mood when on an SSRI.
As for prescribing it, I suspect my doctor would know the information as listed in PDR (Physician's Desk Reference). In other words, a professional researches the most current and accurate drug information and compiles it into a thick resource. I also have read and believe that doctors use their experience with other patients. When my doctor first prescribed Lexapro to me, she described the side-effects that her own patients had experienced. There is published information on known side-effects and some of the incidences that have been reported concerning that drug but my doctor also used her knowledge with her own patients. I researched the drug and discovered that a lot of books confirmed her claim that it had the least amount of side-effects and less drug interaction concerns.
As for efficacy, I have heard of some studies finding them to not be much better than placebo but I find that Lexapro works for me. Is it the placebo effect? I don't know. I doubt it though. I am not sure how many studies show them as not effective and how many show them as effective. I suspect that one of the other posters might know that better. Do I find myself creeped out by the idea of taking a drug? You bet. I told my doctor that I am scared of drugs but I tried talk to for around six months before trying a drug. I have read that many of the anti-depressants are pretty close to each other in effectiveness and doctors try to chose one based on side-effects. I can see this. If the client is sleepy all the time, maybe an activting anti-depressant might be more helpful that one with a side-effect of drowsiness. Does the person care more about keeping his/her sex drive or the desire not to gain weight? What is the person's most annoying symptom? My most annoying symptom was sleep. Also I have read that anti-depressants work better on vegetative symptoms such as sleeping problems, lack of energy etc. So, maybe some depressions are more psychological while some is both psychological and biological. Then some people have more of a biological issue with no or little psychological issues. If so, this might also cause problems with the studies. Depression can be different for different people.
Of course I have no real expertise in the field, I am just a biology graduate who did some reading in an attempt to decide whether or not to try an anti-depressant.