Lexapro is an antidepressant in a group of drugs called selective serotonin reuptake inhibitor. To weight gain and its high price. Evidence suggests an imbalance of serotonin, a natural substance in the brain that may become unbalanced and cause depression or anxiety. Lexapro is actually an updated version of an older anti-depressant called Celexa. If you experience Lexapro side effects occur. Lexapro does cause problems when you are operating a vehicle or driving heavy machinery. Lexapro anti depressant has helped millions and is continuing to help millions. This medication may cause dizziness or drowsiness.