Evolution and Posttraumatic Stress: Disorders of Vigilance and Defence

239 Pages·2005·3.451 MB·English

by  Chris Cantor

Evolution and
Posttraumatic Stress
Posttraumatic stress disorder (PTSD) remains one of the most con-
tentious and poorly understood psychiatric disorders. Evolution
and Posttraumatic Stress provides a valuable new perspective on its
nature and causes.
This book is the first to examine PTSD from an evolutionary
perspective. Beginning with a review of conventional theories, Chris
Cantor provides a clear and succinct overview of the history, clinical
features and epidemiology of PTSD before going on to introduce
and integrate evolutionary theory. Subjects discussed include:
• A clinical perspective of PTSD.
• The evolution of human defensive behaviours.
• Defence in overdrive – evolution, mammalian defences and
PTSD.
This original presentation of PTSD as a defensive strategy describes
how the use of evolutionary theory provides a more coherent and
successful model for diagnosis and treatment, greatly improving
understanding of usually mystifying symptoms. It will be of great
interest to psychiatrists, psychologists, psychotherapists, sociologists
and anthropologists.
Chris Cantor is Adjunct Senior Lecturer in Psychiatry at the
University of Queensland, Australia.

Evolution and
Posttraumatic Stress
Disorders of vigilance and defence
Chris Cantor
First published 2005
by Routledge
27 Church Road, Hove, East Sussex BN3 2FA
Simultaneously published in the USA and Canada
by Routledge
270 Madison Avenue, New York NY 10016
Routledge is an imprint of the Taylor & Francis Group
This edition published in the Taylor & Francis e-Library, 2005.
“To purchase your own copy of this or any of Taylor & Francis or Routledge’s
collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.”
Copyright © 2005 Chris Cantor
All rights reserved. No part of this book may be reprinted or
reproduced or utilized in any form or by any electronic,
mechanical, or other means, now known or hereafter
invented, including photocopying and recording, or in any
information storage or retrieval system, without permission in
writing from the publishers.
This publication has been produced with paper manufactured
to strict environmental standards and with pulp derived from
sustainable forests.
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
Library of Congress Cataloging-in-Publication Data
Cantor, Chris.
Evolution and posttraumatic stress: disorders of vigilance and
defence / Chris Cantor.
p. cm.
Includes bibliographical references and index.
ISBN 1-58391-770-5 (hbk) – ISBN 1-58391-771-3 (pbk)
1. Post-traumatic stress disorder. 2. Evolutionary psychology.
[DNLM: 1. Evolution. 2. Stress Disorders, Post-Traumatic.
3. Behavior, Animal. 4. Genetics, Behavioral. 5. Psychology,
Comparative. ] I. Title.
RC552.P67C36 2005
616.85′21–dc22 2005001407
ISBN 0-203-02844-9 Master e-book ISBN
ISBN 1-58391-770-5 (hbk)
ISBN 1-58391-771-3 (pbk)
To Linda Mealey – thanks

Contents
Preface xiii
Acknowledgements xv
Introduction 1
The structure of the book 2
PART I
Posttraumatic stress disorder: an introduction 5
1 A brief history of PTSD 7
The long and the short 7
The world wars 9
Early conceptualization of traumatic reactions 11
Science and politics in recent times 12
Muddy waters 14
Early ethological speculations 16
Summary 18
2 A clinical perspective of PTSD 19
PTSD as a concept 19
The DSM-IV criteria for PTSD 20
The nature of traumas and frequency of PTSD 23
The influence of perception 24
Trauma and symptom course 26
War studies 27
viii Contents
Complex PTSD 28
Delayed PTSD 30
Subthreshold PTSD 31
Summary 31
3 Conventional theories of PTSD 33
Learning, controllability and predictability 34
Of rats and men 34
Learned helplessness 36
Controllability and predictability 37
Flaws of overly simplistic conditioning theories 38
Preparedness 40
Observations from combat and torture 43
Controllability and PTSD 43
Summary 44
Myopia and twenty-first century neuroscience 45
Proximate versus distal perspectives 45
The triune brain 46
Twenty-first century? 48
Facial emotions 50
Essential neuroanatomy of PTSD 51
Neurochemistry and PTSD 56
Conditioning studies and functional anatomy 60
Neurogenesis and plasticity 61
Summary 63
Indelible memories, forgetfulness and defence 63
The evolution of memory and awareness 64
State-dependent memory and memory laws 64
Fear as a component of a behavioural module 66
Special police training insights 68
Emotions as communicational states 70
Information processing and PTSD 70
Summary 75
Contents ix
PART II
Evolution and posttraumatic stress disorders 77
4 The evolution of human defensive behaviours 79
Ancestral origins and predation pressure 79
In the beginning ... 79
Learning and defence 81
Common evolutionary misconceptions 82
Summary 84
Reptilian and mammalian defences 84
Predation and defence 85
Reptilian defences 86
Mammalian defences 90
Adaptive conservatism and evolutionarily stable strategies 95
Summary 96
Predator avoidance, anti-predator strategies
and foraging 96
The functions of emotions 96
The ecology of threats 98
Influences of predation 99
Vigilance, prey decision-making and activity 100
Costs, benefits and predator-sensitive foraging 103
Primate foraging decision studies 106
Summary 107
Family foibles and early hominids 107
The pathway to humankind 107
Hominids 108
Primate and great ape extrapolations 111
Group size in great apes 112
Primate research limitations 116
Paleoanthropology 118
Hominids as scavengers and prey 119
Hunter-gatherers 121
Summary 122