LETTERS

A Reply SIR:

TO THE

EDITOR

to a Rebuttal I appreciate

schizophrenia the

opportunity

to react

to Dr.

Kety’s

re-

sponse (1) to my commentary (2) on his study of genetics and schizophrenia (October 1976 issue). Dr. Kety suggests that I have engaged in careless reading of his papers, and documents this suggestion with excerpts from my critique, followed by ‘answers’ from his papers. He opens this documentation ofcareless reading with a reference to my complaint about having had to guess which statistical test had been used to analyze the data. Dr. Kety suggests that the test was specified by the phrase ‘p. one sided probability from exact distnibution=0.0072” (1, p. 1134). Many readers willjoin me in wondering which exact distnibution-multinomial? binomial? Poisson? Fisher’s? Although only readers with a high energy level, high interest. and freedom from statisticophobia” will check Dr. Kety’s ‘rebuttal’ of my position point by point, I would like to offer three guidelines for those who do examine our exchange in detail. I . Follow carefully the specific references cited under Dr. Kety’s heading, ‘our paper. My commentary applied only to his original study, which contained carefully imposed controls on defining schizophrenics. However, several of the rebuttals come from a subsequent expansion of the original study that added schizophrenic subjects defined on the basis of one interview conducted by one of the authors. I did not and will not now consider this expanded study in my arguments. ‘

‘

‘

‘ ‘

‘

‘

‘

2.

Note

that

that, when away, the index and gory; thus, “genetic’

there

‘ ‘

was

no direct

response

to my

objection

diagnosis

Note

that

the research

my

general

as

suicide,

it is

of parents for index in availability.

methodological

comment

about

design

was transformed by Dr. Kety into a position in favor of an SES interpretation of schizophrenic, which he then refuted. However, my comments on socially adaptive attributes were intended to address Dr. Kety’s that

theme

“illness”

schizophrenia

gene.

is associated

Ifthis

with

idea is pursued

a destructive

it is important

to estab-

lish whether contrasts between index and control groups were due to superiority of the control group and/or to infenionity ofthe index group. One does not need Dr. Kety’s additional observations (1, p. 1135) about how many cases were

born

of married

couples

to refute

a social

adaptation

inter-

pretation ofthe half-sibling ‘ ‘this formulation, like

findings. Moreover. I commented, the genetic (disadvantage) inter-

pretation,

ofthe

falters

tween index atastalemate”(2,p.

In spite invoking plying

because

and

control

of Dr.

Kety’s

which

differences

the does

be-

the argument

remains

of careless

information, test

to find

Thus

suggestions

of additional a statistical

failure

parents. 1132).

not

reading

fact

remains violate the

and

that apindepen-

dence assumption to the results obtained from the original carefully controlled samples shows that significant differences occurred only in the half-sibling category. Because the parent category did not show a difference between index and control groups, the results cannot be explained by either the genetic advantage (control) or genetic disadvantage (index) nor

does

a reasonable

environmental

hypothesis

‘

these

factors,

he

reasons,

make

would

be found

of schizophrenia

nosis ofschizophnenia original paper indicated

1466

manifested

account for the peculiar findings. All we know at present is that a relatively small sample of adoptees showed an understandably high proportion of half-siblings and significantly more half-siblings of the index group had schizophrenia.

it less

likely

in the

parent

that

REFERENCES a

date-

gory than in the half-sibling category. One can see how these factors (not to mention divorce) might affect the sibling dategory but not the parent category as defined in the first study, in which the schizophrenic adoptees studied had obviously already survived the possible problems of parental infertility and abortion. Suicide would not have precluded tagging parental schizophrenia because the diagnosis was made through the population register and hospital records; interviewing living parents was not required. One does need to presume that parental schizophrenia did not first appear as suicide, that is, the parent would have had to manifest schizophrenic behaviors to a degree sufficient to establish the diag-

cated Given

3.

initially

to conclude that the samples subjects were comparable

hypothesis;

all the detail and statistical hocus-pocus is boiled main finding is that the major difference between control families occurred in the half-sibling catethe weaker the consanguinity, the greater the effect. Dr. Kety appears to respond to this objection with the observation that schizophrenic subjects are more than normally vulnerable to infertility, abortion, and suicide;

is rarely

reasonable and control

before

committing

suicide.

Dr.

JPsychiatry

/33:12,

December

1976

2.

.

Kety SS: Studies mental variables

designed to disentangle in schizophrenia: some

genetic and epistemological

environques-

tions and answers. Am J Psychiatry 133: I 134-I 136, 1976 Benjamin LS: A reconsideration of the Kety and associates study of genetic factors in the transmission of schizophrenia. Am J Psychiatry 133:1129-1133, 1976

LORNA

S.

PH.D.

BENJAMIN,

Madison,

on

Sexism

Wis.

in the Language

Kety’s

that 63 biological parents were lofor both the 33 index cases and the 33 control cases. this comparability of numbers, and presuming that Am

I

SIR:

I have

noticed

that

many

tried to be nonsexist in their use by using he or she’ to describe ‘ ‘

‘

authors

have For example, authors at-

in the Journal

of pronouns. psychiatrists,