Ativan is the trade name for a prescription drug called lorazepam, a medication that belongs to a family of tranquilizers called benzodiazepines. Ativan is prescribed for several important reasons, including the treatment of anxiety, sleep disturbances, muscle spasms, alcohol withdrawal, and seizure disorders. But Ativan can be habit-forming if it is taken for nonmedical reasons or if the user takes more than the prescribed dose.