From what the Doctors have told us, my fiance's reaction was pretty extreme, but it was not unheard of with Lexapro. She had a "drug induced psychotic episode", which means she had a total meltdown. I found her in our bedroom, on the floor, in a sleeping bag screaming "I have money and I am going home now" She has no memory of this whatsoever. She remained in an almost semi-coma for almost 3 weeks.
No, she has not had this type of reaction to medications before or since. She does have high blood pressure, but the doctor at the hospital said that even that condtion shouldn't have caused this type of reaction. What we did find out is that you must take the medication at approximately the same time every day, and never raise the dosage more than 5mgs at a time. This type of anti-depressant works much differently than any of the more popular types and is processed by the body through the liver, so make sure you have had a liver function test before taking this drug.
She also had a small stroke, which the doctors said they are pretty sure was also caused by the Lexapro and her blood pressure elevating so quickly when the "quack" who was her doctor kept changing her dosage in 10mg amounts (she started with 10mgs, then he had her take 20mgs for about a week, then put her back on 10mgs, then tried 20mgs again - all within a 2 week period of time)
She does have some special medical needs and an unusual history, she had gastroplasmy surgery about 10 years ago, and apparently the "quack" did not take this into consideration, and there is no research available on whether or not this surgery and the effects had anything to do with the way Lexapro worked in her system.
All in all, just be careful, make sure you have a good doctor, (check out the AMA site) and always use the same pharmacy for all your prescriptions, this way they can help track your meds and whether or not you are taking something that could interact with the Lexapro.
Hope this helped, if you have any other questions, let me know.