Instinct or Learned?

A Patient Of A Psychiatrist Suffers Recurring Nightmares Concerning The Oklahoma City Bombing. The Psychiatrist Suspects That The Patient Is Experiencing Nightmares Caused By Another Personality In His Head And This Personality X Is Attempting To Take Control Of The Patient. The Psychiatrist Uses Hypnosis To Access X Which He Does. The Patient Is Losing His Ability To Fight Off This Personality On A Daily Basis. In Order To Eliminate X The Doctor Must Know More About Him If Possible So The Doctor Also Becomes A Detective. In The Process The Doctor Discovers That The Personality Is A Killer Which Accelerates His Need To Eliminate This Vial Personality. With The Aid Of A Specialist The Psychiatrist Discovers An Unlikely Surgery To Remove A Small Part Of The Patient Brain Housing The Evil Personality. In Performing His Research The Psychiatrist Discovers The Answer To The Question Of Instinct Or Learned.