Paprika

In the near future, a revolutionary new psychotherapy treatment called dream therapy has been invented. A device called the "DC Mini" allows the user to view people's dreams. The head of the team working on this treatment, Doctor Atsuko Chiba, begins using the machine illegally to help psychiatric patients outside the research facility, using her alter-ego "Paprika", a sentient persona that she assumes in the dream world. Read more on Wikipedia.