George - I don't know the answer to the pallidotomy/personality change question, but I wonder if your friend has tried Prozac, Paxil, Zoloft, or Effexor. These SSRIs (Selective Seratonin Reuptake Inhibitors) are thought to help not only depression, but OCD (Obsessive/Compulsive Disorder) as well. Gambling is generally considered an OCD. Good luck. Margie