References 333
brain activity requires energy and this energy comes from in-
creased metabolic activity in the brain area doing the work.
PET and CT scans begin with an injection of briefly acting
radio-active material into the blood stream to mark changes
in blood flow and blood concentration, thereby indicating
where the increased metabolic activity is taking place. These
scan methods require keeping radioactive material in the lab-
oratory, and the injections are somewhat intrusive. These
methods also are expensive and are limited as to the clarity of
the images of brain structure they provide.
For all of these reasons, use of these scans has been gen-
erally superseded by magnetic resonance imaging. Not until
1959 was MRI used for medical diagnosis, and not until the
1970s did it came into general use for body imaging. MRI
could detect natural changes in blood oxygen levels (an index
of metabolic activity) without using radioactive materials.
High-speed scanning of the whole brain in a few milliseconds
enabled the investigator to study rapid localized brain activ-
ity changes during mental activity. Additionally, improve-
ments in EEG made it possible to study the rise and fall of
electrophysiological activity at specific points in the brain in
real time.
The New Genetics
With the discovery of the double-helix DNA, the genetics of
psychopathology passed from dependence upon inference
from studies of twins to direct identification of genetic anom-
alies. One of the first outcomes of genetic studies of the
psychoses was the evidence that no one-gene–one-disorder
relationship existed. In the case of schizophrenia alone,
Gottesman and Moldin (1998) reported on several studies be-
tween 1994 and 1997 that implicated seven different chro-
mosomal regions in the genetics of schizophrenia.
Paradoxically, the increased sophistication of method
provided by brain imaging and genetic analysis has not
suggested that we are nearing a clear answer to the historic
questions about the biology of mental illness. Instead it has
gradually revealed the complexity of interactions between
brain areas, the heterogeneity of brain anomalies in the psy-
choses, and the heterogeneity of the genetic factors in what
appear to be unitary diagnostic categories.
Experimental Psychopathology
Experimental psychological work in psychopathology in the
tradition of Kraepelin, Shakow, and others had also dwindled
by midcentury. Much of this reflected the influence of psy-
choanalysis, which asserted that the answers to questions of
etiology were already known and that experimental research
was not only irrelevant to the question but antithetical to the
analytic method. Experimental research in psychopathology
revived from the 1950s onward, extending in various direc-
tions, both behavioral and biopsychological. Progress of ex-
perimental work in psychopathology mirrored ongoing
changes within general psychology and the neural sciences.
Experimental work itself was greatly facilitated by the devel-
opment of desktop computers, which replaced earlier bulky
equipment. Computer portability made it possible to bring
the laboratory to the patient rather than vice versa, thereby
extending the kinds of sample that could be obtained.
By the final decade of the twentieth century, experimental
investigations of psychotic patients focused mainly on the as-
sociation between brain structure and function, on one hand,
and cognitive and emotional processes on the other. As an il-
lustration of the changing emphases, we might note that by
1991 biological research on schizophrenia—a previously
“functional” psychosis comprised four of the five volumes of
theHandbook of Schizophrenia(Nasrallah, 1991). It was
now regarded as an obviously biological disorder.
INTO THE TWENTY-FIRST CENTURY
Looking backward from the vantage point of the new millen-
nium, we see certain themes recurring in cyclical form. The
dilemma posed by the need to care for persons unable to care
for themselves versus the need to respect individual rights and
liberties to make personal decisions leads to a cycle in which
society creates institutions to provide the necessary care and
later discharges the patients on civil rights principles. Ad-
vances made in technologies for other purposes prove to have
significant effects in forwarding our understanding of psy-
chopathology investigations and treatments. The microscope,
the x-ray, electroencephalography, and brain imaging are ex-
amples of this. The emphasis on genetics and brain function
shifts in time to an emphasis on social/environmental factors
in the genesis of behavior. Themes within psychology in gen-
eral, mostly significant but sometimes faddish, find reflection
in psychopathology research trends. What is clear is that with
progress our questions are becoming more sophisticated, and
our answers more complicated.
REFERENCES
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