A driver I know, (he has since retired), used to take 200 mg of Lamictal on a daily basis. Lamictal is used for depression, but mostly for bipolarity, like in his case. I remember he needed to bring a note from his psychiatrist once a year for his DOT medical and give a copy to his manager. The note stated that the medication would not interfere with his driving capabilities. That was FedEx's way of protecting themselves in case of an incident, or worse, an accident involving this employee.