Yawning is a common phenomenon that is an
expression of certain physiological and
psychological states, yet it bas received
remarkably little attention in the medical
literature. Dumpert (1921), Hauptmann (1920),
and Lewy (1921) reached some conclusions
regarding the nature of yawning in connection
with observations of patients with encephalitis
lethargica; however, after the 1920s the subject
was again disregarded. On the basis of certain
clinical and experimental observations which may
have some psychiatric significance and which, to
my knowledge, have not yet been described, a
review of the matter of yawning appeared
justified. [...]
Clinical Observations : It is an old
clinical observation (Russell 1891; Geigel 1908)
that persons suffering from an acute physical
illness never yawn as long as their condition is
serious. Nurses have learned to recognize
the return of yawning as a sign of patients'
convalescence, particularly in those patients
who have infectious diseases. The literature,
however, reports few observations regarding
yawning in psychotic patients, although
Hauptmann (1920) made mention of its possible
significance.
Some time ago I was struck by the conspicuous
scarcity of yawning among mental
patients. I informally recorded the
incidence of people yawning in public
gatherings, on buses, in restaurants, at
scientific meetings, and on mental hospital
wards. These observations confirmed my
impression that yawning among the mentally ill
is unusually rare. There were two exceptions:
patients receiving large doses of sedatives and
those diagnosed as suffering from organic brain
syndrome. Of course, the absence of yawning in
patients with psychoses associated with constant
psychomotor excitement or increased nervous
tension was not surprising since excitement or
emotional tension usually excludes the
occurrence of yawning in normal individuals.
However, the majority of patients I observed
were quiet, inactive, indifferent persons
suffering from schizophrenia. Their failure to
yawn requires an explanation.
One of the most consistent physiological
findings about patients with schizophrenia is
defective homeostasis. The schizophrenic
patient's ability to adjust to changes in the
internal milieu is impaired. Slight reductions
of the schizophrenic subject's brain metabolism
would, therefore, provoke a homeostatic response
less easily than in a normal person. Yawning
might not be elicited unless the yawning
provoking stimulus assumes an unusual strength
such as that provided by hypoglycemia or by
barbiturates.
As I have mentioned, the principal
psychological agent to produce
yawning-boredom-is an affect characterized by an
extraverted attitude, a searching tendency
toward reality. The schizophrenic subject's
typical withdrawal from reality and his
affective blunting make it almost impossible for
him to be truly bored; his passivity,
indifference, and daydreaming must not be
confused with boredom. In addition, the
schizophrenic individual can hardly be expected
to imitate unconsciously the yawning of another
person since he is not likely to transfer
sufficient interest to other persons in his
surroundings. Therefore, when a schizophrenic
patient yawns as a result of boredom or
unconmous imitation, it shows that the patient's
contact with reality is not entirely lost and
that he is making an effort to maintain it. In
fact, when any psychiatric patient yawns, it is
a signal that he is in an accessible mood,
regardless of his general mental state or
diagnosis.
Of course, yawning is by no means completely
absent in schizophrenic patients. Its incidence,
however, appears to be much lower in
schizophrenia than in normal mental conditions
or in other mental diseases. The occurrence of
yawning in early schizophrenia may be evaluated
as a favorable sign; however, it seems to be of
ominous significance in chronic schizophrenia.
One may theorize that yawning in the acute
schizophrenic patient is the reflection of a
fairly intact homeostatic system and possibly
the expression of the patient's efforts to
retain his contact with reality. In the chronic
stages of the disease, yawning may be indicative
of structural brain changes and the formation of
a new, permanent, and pathological relationship
to the outside world, characterized by
complacency and the complete loss of the inner
stress and tension that should accompany even
partial insight.
Experimental Induction of Yawning :
Yawning is an elusive phenomenon and lends
itself poorly to experimental investigation. It
is usually difficult, if not impossible, to
determine which psychic or somatic cause or
combination of causes is actually responsible
for spontaneous yawning.
In an attempt to elicit yawning under fairly
uniform and observable conditions, 180 mental
patients were administered a standardized
cerebral depressant that would bring into action
the homeostatic function of yawning.
Psychological factors, such as an intention to
remain awake and in contact with the
environment, could have been present but were
certainly in the background as yawning-producing
agents in these cases. The subjects selected to
participate in the experiment were divided into
three groups of sixty patients each. Group I
consisted of only those patients who, beyond any
doubt, had been recognized by several staff
members as schizophrenic and who presented no
atypical features. Group II included only those
patients suffering from a variety of psychoses
caused by and associated with neurological brain
lesions. Group III was made up of persons with
miscellaneous functional mental disorders that
did not belong in either the schizophrenic or in
the "organic" group.
These 180 patients were intravenously
administered a 3 percent solution of
pentobarbital, a barbiturate, usually at a rate
of not more than 1 cc per 30 seconds. The
investigator carried on a running conversation
with the patient during the injection, telling
him that the injection would not hurt or
incommodate him in uny way but would make him
feel sleepy. When yawning occurred, the reaction
was counted as positive and the injection was
discontinued, unless a more profound narcosis
was desired for reasons other than the
experiment. When no yawning occurred after a
maximum of 0.3 g of pentobarbital (10 cc of the
3 percent solution) had been administered, the
injection was terminated and the reaction was
counted as negative.
In some cases, yawning occurred frequently
after about 0.15 g of pentobarbital had been
injected. At the same time, the patient's speech
became slurred and he stated that he felt dizzy,
lightheaded, or drowsy. His respiration then
became shallow and infrequent; yawning occurred
frequently at this stage, too. As a rule,
respiration became regular again within a minute
or two, and the patient then slept for several
hours if left undisturbed. In other cases,
yawning was delayed and appeared after the
patient had passed from the somnolent stage into
profound sleep. Therefore, a reaction was
counted as negative only when yawning was not
observed during the injection or within 90
seconds following it. Patients who did not yawn
often sighed deeply when they began to feel
drowsy; however, yawning was defined as an
inspiration accompanied by tonic contraction of
the facial muscles and by opening of the
mouth.
The difference in the incidence of induced
yawning in schizophrenic subjects as compared
with those suffering from a psychosis with
structural brain changes is evident and of
statistical significance (X2 = 26.38; df = 2; p
< 0.001): 26.7 percent positive responses in
schizophrenic patients against 71.7 percent
positive responses in patients with organic
brain syndrome. The positive responses for the
miscellaneous group hold a middle position. As
with spontaneous yawning, induced yawning was
less likely to occur in tense, excited, or
acutely ill individuals than in quiet,
cooperative patients. Very resistive or excited
patients showed little response to the
pentobarbital injection. Other patients who
expressed marked euphoria or depression usually
did not yawn. A general rule seems to be that,
ceteris paribus 1 yawning is favored by the
absence of psychomotor excitement, emotional
tension, and acute, active illness. Thus a
depressed patient in a depressive stupor or a
patient in a manic delirium would probably fail
to show this response.
Within Group III, a distinct majority of
psychoneurotic patients showed negative yawning
reactions. The psychoneurotic individual behaves
like the schizophrenic patient in responding to
the sudden reduction of cerebral function,
especially when anxiety and obsessive symptoms
are prominent. Among those with affective
psychoses, lhe: were more negative responses in
the manic-depressive group an positive responses
in the involutional melancholia group.
Aside from the quantitative differences among
the three groups, there were also qualitative
differences. If yawning occurred in
schizophrenic patients, it usually appeared in a
peculiar, short, superficial manner and was not
repeated, while the yawning of a patient with
structural brain lesion tended to be frequent,
deep, and prolonged. One patient, suffering from
involutional melancholia without evident
cerebral lesion, yawned so forcefully after
awakening from the pentobarbital narcosis that
he dislocated his jaw and required manual
reduction. As with spontaneous yawning, the
induced yawning occurring in early schizophrenia
seemed to have favorable significance, whereas
in chronic cases it seemed to be evidence of
marked deterioration.
In one particular case, the yawning response
to the pentobarbital injection gave a diagnostic
hint. A Chinese man was admitted to the hospital
because of peculiar behavior and general
inertia. Language difficulties prevented the
taking of an adequate history frorn the
relatives and made the psychiatric examination
of the patient difficult. The physical
examination yielded no definite results, and a
provisional diagnosis of simple schizophrenia
was made. However, the patient showed such a
frequent and intensive yawning response to
pentobarbital that the staff doubted that they
were dealing with a schizophrenic individual.
The spinal fluid findings then revealed that the
patient was suffering from general paresis.
Conclusions
(1) Yawning is a phylogenetically and
ontogenetically old reflex that occurs under
somatic conditions which seem to be
characterized by a reduction of brain
metabolism.
(2) There is reasonable support for the view
that yawning originated as a self-adjusting
mechanism of the organism, a homeostatic reflex
which operates through the tonic contraction of
large muscle groups and temporarily improves
circulation in general and blood flow to the
brain in particular.
(3) The principal psychological reasons for
yawning are boredom and unconscious
imitation.
(4) Boredom is an affect characterized by an
extraverted attitude.
(5) Unconscious imitation requires
transferring interest to something in the
outside world.
(6) Yawning is a signal that the person is
making an effort to maintain contact with the
outside world.
(7) Psychotic persons yawn rarely, except
when suffering from organic brain syndrome.
(8) Spontaneous yawning in a psychotic,
particularly a schizophrenic, individual may be
a signal that he is in an accessible mood.
(9) When yawning is induced experimentally by
pharmacosedation, the responses of schizophrenic
subjects differ significantly from those of
psychotic subjects with structural brain
lesions.
(10) In persons with psychiatric conditions,
yawning may assume the value of a clinical
symptom with diagnostic and prognostic
implications.
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