I have been on it for seven months. I started at 10 mg and felt like throwing up. My doctor suggested that I take it in the morning because it might cause insomnia and insomnia was almost the primary reason for seeking out treatment. I did not notice a decrease in anxiety until a month or month and a half after starting it. I suggest that you TRY to give it a month to see if it works for you. The side effects should decrease or go away once your body adjust to the drug. I still feel slightly dizzy at times. I sometimes feel a bit sleepy, but I am not sure if that is the drug or the original problem (I had a strong lack of energy before starting Lexapro). If you want to try to take it at night. There is no reason why you can't try that. People take it when the side effects that they experience will be less disruptive to them.