This is a most
significant book, published at a crucial time and attempting to answer some of
the most fundamental questions in research into one of the most pressing of
current issues. In 20 chapters some of the most influential researchers across
the world canvass the state of the art of the epidemiology of schizophrenia
from basic design questions (what can be measured and how is this possible?),
to John McGrath’s final consideration of the possibilities that accurate
epidemiology hold for the prevention of the disorder.

There are five explicit themes in
the book: social epidemiology, developmental epidemiology, genetic
epidemiology, special issues (such as physical illness, substance abuse and
suicide) and future directions on classification, service planning and even
prevention. Each section deals with its subject matter in impressive detail,
clearly and articulately describes the issues of contention and controversy,
debunking unsubstantiated assertions and weighing carefully the best available
evidence. Each chapter within the sub-sections is prudent in its claims and
careful in its assertions. It may be suggested that the authors would generally
agree that while there is much about which we can say we are certain, the most
important of these is the knowledge that there is even more that is still to be
determined.

There is an
underlying critique of much of the conventional approach to epidemiological
research in schizophrenia and, in particular, and an emphasis on questions
related to the social environment. For example, that the rate of schizophrenia
seems to significantly higher in migrant groups, particularly in first and
second generation African-Caribbean immigrants, has, of course, been hotly
debated for many years. Is it more of a case of diagnostic inconsistency than
some real difference in incidence? Is it a function of social values rather
than impartial science? Is it more indicative of racial stereotypes or the
effects of social circumstances? Jane Boydell and Robin Murray from the
Institute of Psychiatry in the UK while dismissing any influence of the season
of birth on incidence, despite the great amount of interest the theory has
generated, also conclude that the evidence that "social and psychological
aetiological factors are operating" and while these may be the same for
all sections of the population, migrants and other minority groups are
"more exposed to them or less protected against them". Their balanced
conclusions reflect a multi-factorial approach that is also found elsewhere in
the text.

Hafner, discussing
the issue of the prodromal stage and the characteristics of early onset
psychosis, argues that the early course taken by the disorder "might be of
far greater importance for further illness and social outcomes than any of the
later stages" and so although it may not yet be possible to predict
outcome from the prodrome, it should be a major focal point for further
research. In this, he is supported by the arguments of Clarke and O’Callaghan,
but they too are cautious about making claims that the evidence cannot yet
support.

There are also
significant chapters dealing with the pre- and perinatal risk factors (it is
suggested that while there may be some evidence to support the effect of second
trimester exposure to some respiratory diseases, low birthweight and retarded
intrauterine growth) there remain methodological problems and it is more
probable in any case that "we are dealing with interactive effects of
prenatal and genetic factors". While genes may "control the
development of the brain and the nervous system … the environment modifies
it". As in childhood development, there are pointers and suggestive
indications, but looking for single factor relationships will be vain. That,
plus the always low relative risk of suffering from the disorder at all, serves
to qualify any claim of prediction.

The section
dealing with the genetic influence is similarly multi-dimensional. Yes, the
genetic factors are undeniable, but No they are not enough by themselves; they
are necessary but not sufficient. There is, it is suggested, significant hope
that investigation of the gene-environment, not gene mapping alone, may yield
clues to the pathways of risk which lead not only to the onset of the disorder,
but its persistence.

The penultimate
section deals with "special factors" and the relationship to, for
example, substance abuse. Here some more provocative claims are made. It is
said that while cannabis use, often a contentious issue, can cause brief
organic reactions, it is probably also an added risk factor for those already
biologically predisposed or significantly vulnerable. Furthermore, it may be an
independent risk factor in its own right. That said, the authors, Murray et al,
add the caveat that such a claim may not withstand rigorous methodological
scrutiny.

It may be fairly
said that this volume will become a standard and valued text for advanced
students for some little while. It does have a cautious, technical and academic
tone, but it is not impenetrable; it just requires close attention. Although it
is well written and has admirable clarity, it is dense at times and may not be
accessible to the less specialized reader. Nevertheless, it is an important
addition to the literature, it summarizes impressively and appraises cogently.
Its conclusions are constructive and balanced. It does not venture much into
the philosophical debates of the disorder itself, but is still infused with a
profound concern for what remains one of the most personally destructive and
burdensome of all illnesses. The final word may go to John McGrath who argues
in the final chapter that basic strategic research needs to go hand-in-hand
with attempts at primary prevention, and the nihilism of the past needs to be
replaced by a sense of determination and urgency. He may call the idea of
primary prevention of schizophrenia "quixotic", but he might also say
that you have to have a dream if you are ever going to have a dream come true.

© 2004
Mark Welch 

Dr
Mark Welch is currently a
Senior Lecturer and Postgraduate Coordinator in The School of
Nursing at the University of Canberra, Australia. His PhD investigated the
representation of madness in popular film, and his other research interests
include the mental health of refugees and victims of torture, and the history
of psychiatric epistemology.

Categories: MentalHealth, Genetics, Psychology