2000k-815 behaviortherapy bereavement death general grieftherapy medical nursing post-traumatic post-traumaticstressdisorder post-traumaticstressdisorder(ptsd) psy022040med105000soc025000psy028000med058180 psychiatric psychiatry psychologicalaspects psychology psychopathology psychotherapy socialscience socialwork stressdisorders suddendeath therapy treatment