I just watched this six part BBC series from 2007, written by the great Steven Moffat who I’ve mentioned before. It’s a sequel to Dr. Jekyll and Mr Hyde set in present day. It’s about his descendant who is genetically cursed with the duality. Kind of like the Incredible Hulk if the Hulk was a brilliant psychopath. It’s available on DVD and from Netflix. I highly recommend it. It’s entertaining as all get out.