The ICD-10 Classification of Mental and Behavioural Disorders
World Health Organization, Geneva, 1992
The schizophrenic disorders are characterized in general by fundamental
and characteristic distortions of thinking and perception, and by
inappropriate or blunted affect. Clear consciousness and intellectual
capacity are usually maintained, although certain cognitive deficits may
evolve in the course of time. The disturbance involves the most basic
functions that give the normal person a feeling of individuality,
uniqueness, and self-direction. The most intimate thoughts, feelings, and
acts are often felt to be known to or shared by others, and explanatory
delusions may develop, to the effect that natural or supernatural forces
are at work to influence the afflicted individual's thoughts and actions
in ways that are often bizarre. The individual may see himself or herself
as the pivot of all that happens. Hallucinations, especially auditory, are
common and may comment on the individual's behaviour or thoughts.
Perception is frequently disturbed in other ways: colours or sounds may
seem unduly vivid or altered in quality, and irrelevant features of
ordinary things may appear more important than the whole object or
situation. Perplexity is also common early on and frequently leads to a
belief that everyday situations possess a special, usually sinister,
meaning intended uniquely for the individual. In the characteristic
schizophrenic disturbance of thinking, peripheral and irrelevant features
of a total concept, which are inhibited in normal directed mental
activity, are brought to the fore and utilized in place of those that are
relevant and appropriate to the situation. Thus thinking becomes vague,
elleptical, and obscure, and its expression in speech sometimes
incomprehensible. Breaks and interpolations in the train of thought are
frequent, and thoughts may seem to be withdrawn by some outside agency.
Mood is characteristically shallow, capricious, or incongruous.
Ambivalence and disturbance of volition may appear as inertia, negativism,
or stupor. Catatonia may be present. The onset may be acute, with
seriously disturbed behaviour, or insidious, with a gradual development of
odd ideas and conduct. The course of the disorder shows equally great
variation and is by no means inevitably chronic or deteriorating (the
course is specified by five-character categories). In a proportion of
cases, which may vary in different cultures and populations, the outcome
is complete, or nearly complete, recovery. The sexes are approximately
equally affected by the onset tends to be later in women.
Although no strictly pathognomonic symptoms can be identified, for
practical purposes it is useful to divide the above symptoms into groups
that have special importance for the diagnosis and often occur together,
such as:
- thought echo, thought insertion or withdrawal, and thought
broadcasting;
- delusions of control, influence, or passivity, clearly referred to
body or limb movements or specific thoughts, actions, or sensations;
delusional perception;
- hallucinatory voices giving a running commentary on the patient's
behaviour, or discussing the patient among themselves, or other types
of hallucinatory voices coming from some part of the body;
- persistent delusions of other kinds that are culturally
inappropriate and completely impossible, such as religious or
political identity, or superhuman powers and abilities (e.g. being
able to control the weather, or being in communication with aliens
from another world);
- persistent hallucinations in any modality, when accompanied either
by fleeting or half-formed delusions without clear affective content,
or by persistent over-valued ideas, or when occurring every day for
weeks or months on end;
- breaks or interpolations in the train of thought, resulting in
incoherence or irrelevant speech, or neologisms;
- catatonic behaviour, such as excitement, posturing, or waxy
flexibility, negativism, mutism, and stupor;
- "negative" symptoms such as marked apathy, paucity of
speech, and blunting or incongruity of emotional responses, usually
resulting in social withdrawal and lowering of social performance; it
must be clear that these are not due to depression or to neuroleptic
medication;
- a significant and consistent change in the overall quality of some
aspects of personal behaviour, manifest as loss of interest,
aimlessness, idleness, a self-absorbed attitude, and social
withdrawal.
Diagnostic Guidelines
The normal requirement for a diagnosis of schizophrenia is that a
minimum of one very clear symptom (and usually two or more if less
clear-cut) belonging to any one of the groups listed as (a) to (d) above,
or symptoms from at least two of the groups referred to as (e) to (h),
should have been clearly present for most of the time during a period of 1
month or more. Conditions meeting such symptomatic requirements but of
duration less than 1 month (whether treated or not) should be diagnosed in
the first instance as acute schizophrenia-like psychotic disorder and are
classified as schizophrenia if the sumptoms persist for longer periods.
Viewed retrospectively, it may be clear that a prodromal phase in which
symptoms and behaviour, such as loss of interest in work, social
activities, and personal appearance and hygiene, together with generalized
anxiety and mild degrees of depression and preoccupation, preceded the
onset of psychotic symptoms by weeks or even months. Because of the
difficulty in timing onset, the 1-month duration criterion applies only to
the specific symptoms listed above and not to any prodromal nonpsychotic
phase.
The diagnosis of schizophrenia should not be made in the presence of
extensive depressive or manic symptoms unless it is clear that
schizophrenic symptoms antedated the affective disturbance. If both
schizophrenic and affective symptoms develop together and are evenly
balanced, the diagnosis of schizoaffective disorder should be made, even
if the schizophrenic symptoms by themselves would have justified the
diagnosis of schizophrenia. Schizophrenia should not be diagnosed in the
presence of overt brain disease or during states of drug intoxication or
withdrawal.
This is the commonest type of schizophrenia in most parts of the world.
The clinical picture is dominated by relatively stable, often paranoid,
delusions, usually accompanied by hallucinations, particularly of the
auditory variety, and perceptual disturbances. Disturbances of affect,
volition, and speech, and catatonic symptoms, are not prominent.
Examples of the most common paranoid symptoms are:
- delusions of persecution, reference, exalted birth, special mission,
bodily change, or jealousy;
- hallucinatory voices that threaten the patient or give commands, or
auditory hallucinations without verbal form, such as whistling,
humming, or laughing;
- hallucinations of smell or taste, or of sexual or other bodily
sensations; visual hallucinations may occur but are rarely
predominant.
Thought disorder may be obvious in acute states, but if so it does not
prevent the typical delusions or hallulcinations from being described
clearly. Affect is usually less blunted than in other varieties of
schizophrenia, but a minor degree of incongruity is common, as are mood
disturbances such as irritability, sudden anger, fearfulness, and
suspicion. "Negative" symptoms such as blunting of affect and
impaired volition are often present but do not dominate the clinical
picture.
The course of paranoid schizophrenia may be episodic, with partial or
complete remissions, or chronic. In chronic cases, the florid symptoms
persist over years and it is difficult to distinguish discrete episodes.
The onset tends to be later than in the hebephrenic and catatonic forms.
Diagnostic Guidelines
The general criteria for a diagnosis of schizophrenia (see introduction
to F20 above) must be satisfied. In addition, hallucinations and/or
delusions must be prominent, and disturbances of affect, volition and
speech, and catatonic symptoms must be relatively inconspicuous. The
hallucinations will usually be of the kind described in (b) and (c) above.
Delusions can be of almost any kind of delusions of control, influence, or
passivity, and persecutory beliefs of various kinds are the most
characteristic.
Includes:
- paraphrenic schizophrenia
Differential diagnosis. It is important to exclude epileptic and
drug-induced psychoses, and to remember that persecutory delusions might
carry little diagnostic weight in people from certain countries or
cultures.
Excludes:
- involutional paranoid state (F22.8)
- paranoia (F22.0)
A form of schizophrenia in which affective changes are prominent,
delusions and hallucinations fleeting and fragmentary, behaviour
irresponsible and unpredictable, and mannerisms common. The mood is
shallow and inappropirate and often accompanied by giggling or
self-satisfied, self-absorbed smiling, or by a lofty manner, grimaces,
mannerisms, pranks, hypochondriacal complaints, and reiterated phrases.
Thought is disorganized and speech rambling and incoherent. There is a
tendency to remain solitary, and behaviour seems empty of purpose and
feeling. This form of schizphrenia usually starts between the ages of 15
and 25 years and tends to have a poor prognosis because of the rapid
development of "negative" symptoms, particularly flattening of
affect and loss of volition.
In addition, disturbances of affect and volition, and thought disorder
are usually prominent. Hallucinations and delusions may be present but are
not usually prominent. Drive and determination are lost and goals
abandoned, so that the patient's behaviour becomes characteristically
aimless and empty of purpose. A superficial and manneristic preoccupation
with religion, philosophy, and other abstract themes may add to the
listener's difficulty in following the train of thought.
Diagnostic Guidelines
The general criteria for a diagnosis of schizophrenia (see introduction
to F20 above) must be satisified. Hebephrenia should normally be diagnosed
for the first time only in adolescents or young adults. The premorbid
personality is characteristically, but not necessarily, rather shy and
solitary. For a confident diagnosis of hebephrenia, a period of 2 or 3
months of continuous observation is usually necessary, in order to ensure
that the characteristic behaviours described above are sustained.
Includes:
- disorganized schizophrenia
- hebephrenia
Prominent psychomotor disturbances are essential and dominant features
and may alternate between extremes such as hyperkinesis and stupor, or
automatic obedience and negativism. Constrained attitudes and postures may
be maintained for long periods. Episodes of violent excitement may be a
striking feature of the condition.
For reasons that are poorly understood, catatonic schizophrenia is now
rarely seen in industrial countries, though it remains common elsewhere.
These catatonic phenomena may be combined with a dream-like (oneiroid)
state with vivid scenic hallucinations.
Diagnostic Guidelines
The general criteria for a diagnosis of schizophrenia (see introduction
to F20 above) must be satisfied. Transitory and isolated catatonic
symptoms may occur in the context of any other subtype of schizophrenia,
but for a diagnosis of catatonic schizophrenia one or more of the
following behaviours should dominate the clinical picture:
- stupor (marked decrease in reactivity to the environment and in
spontaneous movements and activity) or mutism;
- excitement (apparently purposeless motor activity, not influenced by
external stimuli);
- posturing (voluntary assumption and maintenance of inappropriate or
bizarre postures);
- negativism (an apparently motiveless resistance to all instructions
or attempts to be moved, or movement in the opposite direction);
- rigidity (maintenance of a rigid posture against efforts to be
moved);
- waxy flexibility (maintenance of limbs and body in externally
imposed positions); and
- other symptoms such as command automatism (automatic compliance with
instructions), and perseveration of words and phrases.
In uncommunicative patients with behavioural manifestations of
catatonic disorder, the diagnosis of schizophrenia may have to be
provisional until adequate evidence of the presence of other symptoms is
obtained. It is also vital to appreciate that catatonic symptoms are not
diagnostic of schizophrenia. A catatonic symptom or symptoms may also be
provoked by brain disease, metabolic disturbances, or alcohol and drugs,
and may also occur in mood disorders.
Includes:
- catatonic stupor
- schizophrenic catalepsy
- schizophrenic catatonia
- schizophrenic flexibilitas cerea
Conditions meeting the general diagnostic criteria for schizophrenia
(see introduction to F20 above) but not conforming to any of the above
subtypes, or exhibiting the features of more than one of them without a
clear predominance of a particular set of diagnostic characteristics. This
rubric should be used only for psychotic conditions (i.e. residual
schizophrenia and post-schizophrenic depression are excluded) and after an
attempt has been made to classify the condition into one of the three
preceding categories.
Diagnostic Guidelines
This category should be reserved for disorders that:
- meet the diagnostic criteria for schizophrenia;
- do not satisfy the criteria for the paranoid, hebephrenic, or
catatonic subtypes;
- do not satisfy the criteria for residual schizophrenia or
post-schizophrenic depression.
Includes:
A depressive episode, which may be prolonged, arising in the aftermath
of a schizophrenic illness. Some schizophrenic symptoms must still be
present but no longer dominate the clinical picture. These persisting
schizophrenic symptoms may be "positive" or
"negative", though the latter are more common. It is uncertain,
and immaterial to the diagnosis, to what extent the depressive symptoms
have merely been uncovered by the resolution of earlier psychotic symptoms
(rather than being a new development) or are an intrinsic part of
schizophrenia rather than a psychological reaction to it. They are rarely
sufficiently severe or extensive to meet criteria for a severe depressive
episode, and it is often difficult to decide which of the patient's
symptoms are due to depression and which to neuroleptic medication or to
the impaired volition and affective flattening of schizophrenia itself.
This depressive disorder is associated with an increased risk of suicide.
Diagnostic Guidelines
The diagnosis should be made only if:
- the patient has had a schizophrenic illness meeting the general
criteria for schizophrenia (see introduction to F20 above) within the
past 12 months;
- some schizophrenic symptoms are still present; and
- the depressive symptoms are prominent and distressing, fulfilling at
least the criteria for a depressive episode, and havew been present
for at least 2 weeks.
If the patient no longer has any schizophrenic symptoms, a depressive
episode should be diagnosed. If schizophrenic symptoms are still florid
and prominent, the diagnosis should remain that of the appropriate
schizophrenic subtype.
A chronic stage in the development of a schizophrenic disorder in which
there has been a clear progression from an early stage (comprising one or
more episodes with psychotic symptoms meeting the general criteria for
schizophrenia described above) to a later stage characterized by
long-term, though not necessarily irreversible, "negative"
symptoms.
Diagnostic Guidelines
For a confident diagnosis, the following requirements should be met:
- prominent "negative" schizophrenic symptoms, i.e.
psychomotor slowing, underactivity, blunting of affect, passivity and
lack of initiative, poverty of quantity or content of speech, poor
nonverbal communication by facial expression, eye contact, voice
modulation, and posture, poor self-care and social performance;
- evidence in the past of at least one clear-cut psychotic episode
meeting the diagnostic criteria for schizophrenia;
- a period of at least 1 year during which the intensity and frequency
of florid symptoms such as delusions and hallucinations have been
minimal or substantially reduced and the "negative"
schizophrenic syndrome has been present;
- absence of dementia or other organic brain disease or disorder, and
of chronic depression or institutionalism sufficient to explain the
negative impairments.
If adequate information about the patient's previous history cannot be
obtained, and it therefore cannot be established that criteria for
schizophrenia have been met at some time in the past, it may be necessary
to make a provisional diagnosis of residual schizophrenia.
Includes:
- chronic undifferentiated schizophrenia
- "Restzustand"
- schizophrenic residual state
An uncommon disorder in which there is an insidious but progressive
development of oddities of conduct, inability to meet the demands of
society, and decline in total performance. Delusions and hallucinations
are not evident, and the disorder is less obviously psychotic than the
hebephrenic, paranoid, and catatonic subtypes of schizophrenia. The
characteristic "negative" features of residual schizophrenia
(e.g. blunting of affect, loss of volition) develop without being preceded
by any overt psychotic symptoms. With increasing social impoverishment,
vagrancy may ensue and the individual may then become self-absorbed, idle,
and aimless.
Diagnostic Guidelines
Simple schizophrenia is a difficult diagnosis to make with any
confidence because it depends on establishing the slowly progressive
development of the characteristic "negative" symptoms of
residual schizophrenia without any history of hallucinations, delusions,
or other manifestations of an earlier psychotic episode, and with
significant changes in personal behaviour, manifest as a marked loss of
interest, idleness, and social withdrawal.
Includes: