Neuropsychological Functioning in Schizophrenia: An Examination of Sex and Gender BonnieJean Thursto

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Neuropsychological Functioning in Schizophrenia 
An Examination of Sex and GenderBonnie-Jean
Thurston-Snoha, M.A.,¹ Richard R.J. Lewine,
Ph.D.¹¹University of Louisville
Results
Introduction
The 2X2X2 ANOVA yielded main effects for sex on
three neuropsychological domains language (F1,
229 6.960, p .009), spatial memory (F1, 256
7.461, p .007), and visual perception (F1, 220
7.015, p .009). In each case, males
performed better than females. Verbal memory
approached significance with females performing
better than males (F1, 255 2.988, p .085).
Main effects of gender were found on five
neuropsychological domains language (F1, 229
18.936, p lt .001) verbal memory (F 1, 255
11.315, p .001), spatial memory (F1, 256
8.279, p .004), visual perception (F1, 220
7.034, p .009), and motor speed (F1, 227
7.506, p .007). In each case, feminine
participants performed better than masculine
participants. Diagnosis effects were found on
each neuropsychological domain with healthy
individuals performing better than patients
(executive function is scored based on error so
lower numbers are associated with better
performance). No interaction effects were
present on any neuropsychological domain. To
examine possible confounding effects of MMPI Sc
and education on the gender results, we conducted
an ANCOVA with Sc and education as covariates in
all instances in which there were significant
gender effects. The results remained virtually
unchanged.  
Sex and gender represent substantially different
concepts and have been demonstrated in an earlier
analysis to yield different insights into
schizophrenia (Lewine, 2004). While there has
been considerable argument about how best to
define or operationalize sex and gender, we
adopt the view that sex refers to
maleness/femaleness rooted in predominantly
physical and biological characteristics. Gender
refers to masculinity/femininity rooted in
sociocultural descriptions (Deaux, 1985 1993
Eagly, 1987 Schaffer, 1980 Stoller, 1968).
Gender can be further refined into concepts such
as gender, gender identity, and gender
role Gender being the psychological or
cultural connotations rather than the biological
ones associated with sex gender identity being
the knowledge and awareness of belonging to one
sex or the other and gender role being the
overt behavior displayed in society to establish
position regarding evaluation of ones gender
(Eagly, 1987 Schaffer, 1980 Stoller, 1968).
While there are consistent sex differences on
selected neuropsychological tasks, there is no
systematic literature on comparable gender
differences.
Discussion
Method
Feminine participants, independent of sex and
diagnosis, performed better than masculine
participants in all the neuropsychological
domains other than executive function and
concentration. These gender differences were not
attributable to age, cognitive deviation (as
measured by the MMPI Sc), or education. The
gender effects were, in short, robust as well as
of moderate size (based on labeling of effect
sizes from Cohen, 1977). We are not the first
to adopt the strategy of simultaneously studying
sex and gender. Daniel, Mathew, and Wilson
(1989), for example, found an expected sex
difference in blood flow (higher for women than
for men). More interestingly, feminine subjects
of both sexes had higher brain blood flow values
than masculine subjects. We failed to find
substantial sex differences in neuropsychological
functioning, and those we did suggested better
performance among men than women. Therefore,
gender did not technically account for sex
differences in our analysis. The results of this
study do, however, clearly demonstrate that sex
and gender are not the same and should not be
used interchangeably, as recommended by Stoller
(1968) almost four decades ago and echoed by more
recent investigators of gender. There are many
questions raised by these findings, not the least
of which are what is actually measured by the mf
Scale and what creates gender. We would like to
clarify that our position regarding gender at
this juncture is strictly descriptive. That is,
gender is undoubtedly a complex product of
biological, psychological, and sociocultural
processes. While sex (barring environmental
accidents) is a more narrowly conceptualized
biological product, gender captures in the
broadest sense the biopsychosocial model of
human behavior.
One hundred and ninety-seven schizophrenia/schizoa
ffective patients and a comparison group of 94
individuals for whom we ruled out both current
and past psychiatric disorder, as well as family
history of psychiatric disorder were assigned a
gender (either feminine or masculine)
depending on the results of the MMPI mf scale.
Using published cut-off scores (Greene, 1980),
we divided the patients into sex typical and sex
atypical groups by sex thereby yielding four
patient groups masculine men (n54), feminine
men (n81), masculine women (n28), and feminine
women (n34). An extensive battery of
neuropsychological tests was administered to all
subjects and combined into seven rationally
derived functional domains language, executive
function, verbal memory, spatial memory, visual
perception, concentration, and motor speed. We
conducted a 2 (sex) X 2 (gender) X 2 (diagnosis)
ANOVA on each neuropsychological domain score, as
we were specifically interested in the types of
neuropsychological function that might differ by
sex and gender. ANCOVAs were also conducted with
education and the MMPI Sc Scale as covariates
when appropriate.
References Cohen, J. (1977). Statistical power
analysis for the behavioral sciences (Rev. ed.).
New York Academic Press. Daniel, D.G., Mathew,
R.J., Wilson, W.H. (1989). Sex roles and
regional cerebral blood flow. Psychiatry
Research, 27(1), 55-64. Deaux, K. (1985). Sex and
gender. Annual Review of Psychology, 36,
49-81. Deaux, K. (1993). Commentary Sorry, wrong
number A reply to Gentiles call. Psychological
Science, 4(2), 125-126. Eagly, A.H. (1987). Sex
differences in social behavior A social-role
interpretation. Hillsdale, NJ Lawrence Erlbaum
Associates, Inc. Greene, R.L. (1980). The MMPI
An interpretive manual. New York Grune
Stratton. Lewine, R. (2004). At issue Sex and
gender in schizophrenia. Schizophrenia Bulletin,
30(4), 755-762. Schaffer, K.F. (1980). Sex-role
issues in mental health. Reading, MA
Addison-Wesley Publishing Company. Stoller, R.J.
(1968). Sex and gender on the development of
masculinity and femininity. New York Science
House.