Journal
of Psychosomatic
Research,
Vol.
20, pp. 351-362.
Individual
Differences Gordon
University
When
preparing
general narrow
of it.
Department
of Experimental
In the end I decided
personality
differences
in the response
any further
comment
to personality
Psychology
trying to give a
it would be better
differences
findings
to do the which
to the tolerance
illus-
of sedative
from me.
variations
a few general
The idea that these differences
is rather more I remember
controversial,
discussing
with a Professor
people
differed
in their reactions
to barbiturates.
quoted
some evidence
that personality
and promptly
Since then the meeting-point
with
changed
between
confirmed
to need
are related
though perhaps
why
I rather nervously to do with
his belief
it.
in the insanity
the subject.
pharmacology
a quite important
the growing
From the research
individual
of Pharmacology
may have something
He looked at me as though I had simply
the
about fifteen years ago, as a very
worker,
has slowly become
about
The fact that there are wide
junior research
of psychologists
remarks
to all drugs is too well-established
less so than it used to he.
ality.
Britain
to focus on one rather
set of research
I can start by making
topic of drugs and personality.
particularly
in Great
the barbiturates.
perhaps
sonality
Printed
in Drug Response
of my topic or, alternatively,
trate work relating
However,
1976.
Claridge
latter and to talk about a specific
drugs, mainly
Press,
this paper I felt I had to decide between
overview aspect
of Oxford,
Pergamon
interest
and the study of per-
focus for research,
in the biological
basis
point of view there are basically
351
of person-
two ways-in
352
G.
to
the
study
problem;
explain
is
through
why people
nearer
of
models
of
drug
two complementary
with
the
found
that
reasons
that
the
drug
Dut then
who had a high had a low
for
wanting
to
starting
simplistic. have
a study I
took
was of
of
acute
that
least
one can much
the
exis-
one against
of
erecting
illustrated which
by the
1 can give
first
part
conductance
group
illtr,
conductance
skin
before
over
in
tile dru;;s
measureOne
group
1 as a
patients
and those
fact
down,
actua!ly
the
those
tvi~ grotlps. went
treated
a11d to my surprise
treatment were
conductance
went up -
being
treatment.
LW:, subgroups:
the
of
their
I:O effect
in
opposite
of level
had absolutely
they
were
schizophrenics psychophysiological
there
a low 1 eve1
one is
is
on behaviour
repeated
the
skin
the
oE skin
1 eve1
if
very
This
1,
a w
from
too
the
do caution
As shown in Figure but
with
out
treatment
level
At
Clearly,
from my own work.
I divided
level.
treatment,
started
took
to a drug
drug works.
and throughout I
themselves.
reactions
many drugs
in which
before
drugs
differences
are
example
measures
whole.
that
ago I carried
both
their
how the
action
phenothiazines
ments
in
in
individual
effects
A few years
marked
who cciects
Patients
who
whereas
t!losc
made -them aut~~~om-
ly more aroused.
01 course about
this
sort
the action
draw attention of
differ
an interesting
ical
like,
an interest
systematic
so-called
of
you
to understanding
tence
of
if
it.
The first
you
or,
Claridge
a simple
0
i experiment
doesn’t
01 phenothiazines to
unitary
the
tact
acti
that
an t:lr any theory
0lI the
tell
pot
brain. which
I)ileu,,thi~~~i:lcs
anythin< %lt. it
very
:nucl:
lll~cs at
least
ir:curp:)ratas is
inc lIplct4.
the nuti.)n
Individual Differences
in Drug
353
Response
10.0
9.0 HIGH AROUSAL - SCHIZOPHRENICS
\
LOW AFwsAL - SCHIZOPHRENICS
LOIPre-Treatment
Changes
FIG. 1.
in galvanic
high and low arousal
The second reason est more
for studying
namely
method
basis of personality.
treatment
in
starts
from an inter-
Here drugs are simply
techniques,
for trying
to
This is the aspect I'm going powerful
technique,
threshold.
for determining
reached
than in drugs themselves.
than twenty years
you may remember, person
drugs and personality
on today and to focus on one particularly
the sedation
It is now more
level during
like other psychophysiological
get at the biological to concentrate
skin conductance
schizophrenics.
in personality
used as tools,
In -Treatment
since Shagass
an individual's
it involved
injecting
some predetermined
(1954)
tolerance
first described
of sedative
drugs and, as
one of the barbiturates
end-point
of sedation.
a
until
The amount
the of
354
G.
drug injected
at that point provided
In his original subsequently
work Shagass
various
by Herrington
Claridge
to get the person
of his sedation
used the EEG to define
other methods
and myself,
a measure
were introduced,
(Claridge
and Herrington,
to double numbers
while
measured
the amount
of drug required
and went
to sleep.
This method
the threshold, including 1960).
he stopped
but
one developed
What we did was We then
he had the injection.
before
proved
threshold.
doubling
numbers
to be simple and reliable
and it is
one which I have used ever since.
During
the late
the sedation
threshold,
mainly
point of view of trying types of psychiatric search
'60's there was a great deal of work on
'50's and early
to develop
disorder,
is not relevant
on psychiatric
here,
patients
objective
particularly
methods
and mainly
for diagnosing
depression.
so I don't intend
from the
to review
Most
various
of that re-
it and in any
case it is now old hat.
I would like to take up one bit of that early work on patients,
However,
the work on neurotics, results
I'm going
the sedation pinning.
However,
it had very little
(Shagass
and Herrington,
neurotics,
like anxiety
0p.cit.j
thresholds
terics and psychopaths. from one of Shagass's
and Jones,
states,
the later
theoretical
that was not true of the work on neurotic
did fit in very well with Eysenck's
by Shagass
sedation
for understanding
Since the aim of most of the research
was empirical
(Claridge
higher
it's important
to talk about.
threshold
that the results Studies
because
showed quite consistently
- that is greater
This is quite well (Shagass
underin
theory of neurosis.
1958) and by Herrington
obsessionals
early papers
groups,
on
and myself that dysthymic
and so on, had significantly drug tolerance illustrated and Kerenyi,
- than hys-
by Figure 1958).
2, taken The
Individual
figure
shows sedation
Differences
threshold
plotted
obsessionality-hysteria
and demonstrates
creasing
and decreasing
obsessionality
in Drug
Response
against
a clinical
how threshold
355
rating of
increases
with in-
hysteria.
HZ
2 OR 2.5 3
3.5 4
4.5 5
5.56 OR MORE
LESS SEDATION
FIG. 2.
Diagram
neurotic
patients
of personality. J. Nerv. Ment.
Now,
illustrating is related
introversion-extraversion
because
of their higher
threshold
(H) and obsessional C. and Kerenyi,A.
quoted
in support
to central
them to support
nervous
his drug postulate
level of arousal,
drugs than extraverts.
in sedation
in
(0) traits B.
141-7).
have been widely
has quoted
sedative
to hysterical
Dis. 1958, 126,
himself
MGM/KG)
how the variation
(From a paper by Shagass,
these results
relating
THRESHOLD
of Eysenck's arousal
theory
and Eysenck
chat introverts,
will show greater
tolerance
But what has often been overlooked
of
is the
356
G. Claridge
fact that the results were obtained bear indirectly normal
subjects,
-is the evidence normal
of whether,
the same relationships that normal
introverts
search
for obvious
and therefore
in an unselected
would hold.
only
group of
In other words, what
show greater
reasons,
during
the heyday
drug tolerance
of sedation
there were very few, if any, large-scale
of the data were collected
patient
research
variations
thresholds
(Claridge,
their normal
evidence.
from small control
op.Sit.);
Those
than
in others
though even here the results
the correlation
was negative
and Jones,
of course,
research
(Claridge,
in the sedation
on it was reported.
interestingly
and
with extraversion
were inconsistent; and sometimes
I also lost interest
related
sometimes positive
threshold
work on normal
in it, though I did by the lack of con-
I had the opportunity subjects
some of the relationships
intrigued
waned and very little
I was puzzled
Then recently
I had been particularly do this.
sedation
was more strongly
threshold
data.
in the normal
if one could unravel
one might
did show higher
Op.Cit.).
interest
some more sedation
subjects.
looked at personality
op.cit.; Claridge
op.cit.1
come back to it from time to time because sistency
re-
groups used in the
threshold
to neuroticism,
(Shagass
of normal
there was no correlation sedation
threshold
that did came up with very
(Shagass andKercryi,
Occasionally
1967).
samples.
In some cases introverts
than extraverts
Herrington,
studies
and even then not all of the studies
within
contradictory
Then,
samples
extraverts?
Perhaps
Most
on the question
on neurotic
and so I decided
by one early paper which
had not measured
sedation
to see
with personality.
This was a paper in 1963 by Rodnight
enough,
to do
threshold
suggested
how
and Gooch who, in the usual way,
Individual
that is using
intravenous
rive an individual
extraversion
has been called
showed
extraversion
in Drug
Response
Instead,
what
measure
between
or neuroticism.
of E and N.
drug tolerance
depended
was determined
oxide tolerance
described
by extraversion
drug tolerance
varied
This in fact worked
and
interaction
according they
related
In other words, between
their
and
because
or negatively
of neuroticism.
by a complex
oxide gas.
That is, they divided
was positively
on the degree
they did was to de-
they then went on to do what
of their data.
to see whether
357
for nitrous
nitrous
However,
to the four quadrants
combinations
that whether
tolerance
no correlation
and then looked
to different
tolerance
'zone analysis'
sample up according neuroticism
barbiturates.
difference
They found absolutely either
Differences
drug
E and N.
Some years after that I had the chance
to carry out a twin study of the
sedation
technique
threshold,
(Claridge
using
and Ross,
1973).
in the twin comparisons, the twin data as normal similar
relationships
of a study I carried
the original
findings
the correlation
minor
with high neuroticism
prior
gynaecological
together
the results
of Rodnight
is entirely
to use
I could pull out
to those found by Rodnight
thiopentone
and Gooch.
sedation
threshold
in Glasgow.
to disc operations
of these two studies,
and extraversion
extraversion
are not significant, across
That plus a
as well as
Table I shows in each case
and those low in neuroticism.
consistent
as part
surgery.
and Gooch.
some of the correlations
correlation
it would be interesting
some more data, this time on thiopentone,
given
between
sodium amytal
in the study, of course, was
out with a group of anaesthetists
those high in neuroticism although
with
sample data and to see whether
patients
I and II bring
interest
with personality
few females undergoing
Tables
My main
but I also thought
Then later on I collected
study involved
our original
to
in two groups:
You can see that, the direction
the three experiments.
is negatively
related
of
In subjects
to tolerance,
358
G.
CORRELATIONS
TABLE I.
BETWEEN
SUBJECTS
Claridge
EXTRAVERSION
AND SEDATION
THRESHOLD
OF HIGH AND LOW NEUROTICISM
High N Groups
Rodnight
1N
and Gooch
Low N Groups
- 0.40
+ 0.72;':
- 0.45
+ 0.65"
_ 0 . 58””
+ 0.20
(Nitrous Oxide)
Claridge
and Ross
(Amylobarbitone
Claridge
Sodium)
et al.
(Thiopentone)
-:; - p
of Psychosomatic
Research,
Vol.
20, pp. 351-362.
Individual
Differences Gordon
University
When
preparing
general narrow
of it.
Department
of Experimental
In the end I decided
personality
differences
in the response
any further
comment
to personality
Psychology
trying to give a
it would be better
differences
findings
to do the which
to the tolerance
illus-
of sedative
from me.
variations
a few general
The idea that these differences
is rather more I remember
controversial,
discussing
with a Professor
people
differed
in their reactions
to barbiturates.
quoted
some evidence
that personality
and promptly
Since then the meeting-point
with
changed
between
confirmed
to need
are related
though perhaps
why
I rather nervously to do with
his belief
it.
in the insanity
the subject.
pharmacology
a quite important
the growing
From the research
individual
of Pharmacology
may have something
He looked at me as though I had simply
the
about fifteen years ago, as a very
worker,
has slowly become
about
The fact that there are wide
junior research
of psychologists
remarks
to all drugs is too well-established
less so than it used to he.
ality.
Britain
to focus on one rather
set of research
I can start by making
topic of drugs and personality.
particularly
in Great
the barbiturates.
perhaps
sonality
Printed
in Drug Response
of my topic or, alternatively,
trate work relating
However,
1976.
Claridge
latter and to talk about a specific
drugs, mainly
Press,
this paper I felt I had to decide between
overview aspect
of Oxford,
Pergamon
interest
and the study of per-
focus for research,
in the biological
basis
point of view there are basically
351
of person-
two ways-in
352
G.
to
the
study
problem;
explain
is
through
why people
nearer
of
models
of
drug
two complementary
with
the
found
that
reasons
that
the
drug
Dut then
who had a high had a low
for
wanting
to
starting
simplistic. have
a study I
took
was of
of
acute
that
least
one can much
the
exis-
one against
of
erecting
illustrated which
by the
1 can give
first
part
conductance
group
illtr,
conductance
skin
before
over
in
tile dru;;s
measureOne
group
1 as a
patients
and those
fact
down,
actua!ly
the
those
tvi~ grotlps. went
treated
a11d to my surprise
treatment were
conductance
went up -
being
treatment.
LW:, subgroups:
the
of
their
I:O effect
in
opposite
of level
had absolutely
they
were
schizophrenics psychophysiological
there
a low 1 eve1
one is
is
on behaviour
repeated
the
skin
the
oE skin
1 eve1
if
very
This
1,
a w
from
too
the
do caution
As shown in Figure but
with
out
treatment
level
At
Clearly,
from my own work.
I divided
level.
treatment,
started
took
to a drug
drug works.
and throughout I
themselves.
reactions
many drugs
in which
before
drugs
differences
are
example
measures
whole.
that
ago I carried
both
their
how the
action
phenothiazines
ments
in
in
individual
effects
A few years
marked
who cciects
Patients
who
whereas
t!losc
made -them aut~~~om-
ly more aroused.
01 course about
this
sort
the action
draw attention of
differ
an interesting
ical
like,
an interest
systematic
so-called
of
you
to understanding
tence
of
if
it.
The first
you
or,
Claridge
a simple
0
i experiment
doesn’t
01 phenothiazines to
unitary
the
tact
acti
that
an t:lr any theory
0lI the
tell
pot
brain. which
I)ileu,,thi~~~i:lcs
anythin< %lt. it
very
:nucl:
lll~cs at
least
ir:curp:)ratas is
inc lIplct4.
the nuti.)n
Individual Differences
in Drug
353
Response
10.0
9.0 HIGH AROUSAL - SCHIZOPHRENICS
\
LOW AFwsAL - SCHIZOPHRENICS
LOIPre-Treatment
Changes
FIG. 1.
in galvanic
high and low arousal
The second reason est more
for studying
namely
method
basis of personality.
treatment
in
starts
from an inter-
Here drugs are simply
techniques,
for trying
to
This is the aspect I'm going powerful
technique,
threshold.
for determining
reached
than in drugs themselves.
than twenty years
you may remember, person
drugs and personality
on today and to focus on one particularly
the sedation
It is now more
level during
like other psychophysiological
get at the biological to concentrate
skin conductance
schizophrenics.
in personality
used as tools,
In -Treatment
since Shagass
an individual's
it involved
injecting
some predetermined
(1954)
tolerance
first described
of sedative
drugs and, as
one of the barbiturates
end-point
of sedation.
a
until
The amount
the of
354
G.
drug injected
at that point provided
In his original subsequently
work Shagass
various
by Herrington
Claridge
to get the person
of his sedation
used the EEG to define
other methods
and myself,
a measure
were introduced,
(Claridge
and Herrington,
to double numbers
while
measured
the amount
of drug required
and went
to sleep.
This method
the threshold, including 1960).
he stopped
but
one developed
What we did was We then
he had the injection.
before
proved
threshold.
doubling
numbers
to be simple and reliable
and it is
one which I have used ever since.
During
the late
the sedation
threshold,
mainly
point of view of trying types of psychiatric search
'60's there was a great deal of work on
'50's and early
to develop
disorder,
is not relevant
on psychiatric
here,
patients
objective
particularly
methods
and mainly
for diagnosing
depression.
so I don't intend
from the
to review
Most
various
of that re-
it and in any
case it is now old hat.
I would like to take up one bit of that early work on patients,
However,
the work on neurotics, results
I'm going
the sedation pinning.
However,
it had very little
(Shagass
and Herrington,
neurotics,
like anxiety
0p.cit.j
thresholds
terics and psychopaths. from one of Shagass's
and Jones,
states,
the later
theoretical
that was not true of the work on neurotic
did fit in very well with Eysenck's
by Shagass
sedation
for understanding
Since the aim of most of the research
was empirical
(Claridge
higher
it's important
to talk about.
threshold
that the results Studies
because
showed quite consistently
- that is greater
This is quite well (Shagass
underin
theory of neurosis.
1958) and by Herrington
obsessionals
early papers
groups,
on
and myself that dysthymic
and so on, had significantly drug tolerance illustrated and Kerenyi,
- than hys-
by Figure 1958).
2, taken The
Individual
figure
shows sedation
Differences
threshold
plotted
obsessionality-hysteria
and demonstrates
creasing
and decreasing
obsessionality
in Drug
Response
against
a clinical
how threshold
355
rating of
increases
with in-
hysteria.
HZ
2 OR 2.5 3
3.5 4
4.5 5
5.56 OR MORE
LESS SEDATION
FIG. 2.
Diagram
neurotic
patients
of personality. J. Nerv. Ment.
Now,
illustrating is related
introversion-extraversion
because
of their higher
threshold
(H) and obsessional C. and Kerenyi,A.
quoted
in support
to central
them to support
nervous
his drug postulate
level of arousal,
drugs than extraverts.
in sedation
in
(0) traits B.
141-7).
have been widely
has quoted
sedative
to hysterical
Dis. 1958, 126,
himself
MGM/KG)
how the variation
(From a paper by Shagass,
these results
relating
THRESHOLD
of Eysenck's arousal
theory
and Eysenck
chat introverts,
will show greater
tolerance
But what has often been overlooked
of
is the
356
G. Claridge
fact that the results were obtained bear indirectly normal
subjects,
-is the evidence normal
of whether,
the same relationships that normal
introverts
search
for obvious
and therefore
in an unselected
would hold.
only
group of
In other words, what
show greater
reasons,
during
the heyday
drug tolerance
of sedation
there were very few, if any, large-scale
of the data were collected
patient
research
variations
thresholds
(Claridge,
their normal
evidence.
from small control
op.Sit.);
Those
than
in others
though even here the results
the correlation
was negative
and Jones,
of course,
research
(Claridge,
in the sedation
on it was reported.
interestingly
and
with extraversion
were inconsistent; and sometimes
I also lost interest
related
sometimes positive
threshold
work on normal
in it, though I did by the lack of con-
I had the opportunity subjects
some of the relationships
intrigued
waned and very little
I was puzzled
Then recently
I had been particularly do this.
sedation
was more strongly
threshold
data.
in the normal
if one could unravel
one might
did show higher
Op.Cit.).
interest
some more sedation
subjects.
looked at personality
op.cit.; Claridge
op.cit.1
come back to it from time to time because sistency
re-
groups used in the
threshold
to neuroticism,
(Shagass
of normal
there was no correlation sedation
threshold
that did came up with very
(Shagass andKercryi,
Occasionally
1967).
samples.
In some cases introverts
than extraverts
Herrington,
studies
and even then not all of the studies
within
contradictory
Then,
samples
extraverts?
Perhaps
Most
on the question
on neurotic
and so I decided
by one early paper which
had not measured
sedation
to see
with personality.
This was a paper in 1963 by Rodnight
enough,
to do
threshold
suggested
how
and Gooch who, in the usual way,
Individual
that is using
intravenous
rive an individual
extraversion
has been called
showed
extraversion
in Drug
Response
Instead,
what
measure
between
or neuroticism.
of E and N.
drug tolerance
depended
was determined
oxide tolerance
described
by extraversion
drug tolerance
varied
This in fact worked
and
interaction
according they
related
In other words, between
their
and
because
or negatively
of neuroticism.
by a complex
oxide gas.
That is, they divided
was positively
on the degree
they did was to de-
they then went on to do what
of their data.
to see whether
357
for nitrous
nitrous
However,
to the four quadrants
combinations
that whether
tolerance
no correlation
and then looked
to different
tolerance
'zone analysis'
sample up according neuroticism
barbiturates.
difference
They found absolutely either
Differences
drug
E and N.
Some years after that I had the chance
to carry out a twin study of the
sedation
technique
threshold,
(Claridge
using
and Ross,
1973).
in the twin comparisons, the twin data as normal similar
relationships
of a study I carried
the original
findings
the correlation
minor
with high neuroticism
prior
gynaecological
together
the results
of Rodnight
is entirely
to use
I could pull out
to those found by Rodnight
thiopentone
and Gooch.
sedation
threshold
in Glasgow.
to disc operations
of these two studies,
and extraversion
extraversion
are not significant, across
That plus a
as well as
Table I shows in each case
and those low in neuroticism.
consistent
as part
surgery.
and Gooch.
some of the correlations
correlation
it would be interesting
some more data, this time on thiopentone,
given
between
sodium amytal
in the study, of course, was
out with a group of anaesthetists
those high in neuroticism although
with
sample data and to see whether
patients
I and II bring
interest
with personality
few females undergoing
Tables
My main
but I also thought
Then later on I collected
study involved
our original
to
in two groups:
You can see that, the direction
the three experiments.
is negatively
related
of
In subjects
to tolerance,
358
G.
CORRELATIONS
TABLE I.
BETWEEN
SUBJECTS
Claridge
EXTRAVERSION
AND SEDATION
THRESHOLD
OF HIGH AND LOW NEUROTICISM
High N Groups
Rodnight
1N
and Gooch
Low N Groups
- 0.40
+ 0.72;':
- 0.45
+ 0.65"
_ 0 . 58””
+ 0.20
(Nitrous Oxide)
Claridge
and Ross
(Amylobarbitone
Claridge
Sodium)
et al.
(Thiopentone)
-:; - p
