# 17 - 6A20 Schizophrenia

# 6A20 Schizophrenia

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
General cultural considerations for schizophrenia and other primary 
psychotic disorders
• Beliefs vary across cultures such that those considered odd or unusual in one culture may 
be normative in another. For example, belief in witchcraft or supernatural forces, or fears 
that transgressing cultural norms can lead to misfortune, are typical in many cultures. 
Distress may be expressed in ways that may be misinterpreted as evidence of psychotic 
symptoms, such as pseudo-hallucinations and overvalued ideas or dissociative experiences 
related to trauma.
• In some cultures, distress due to social circumstances may be expressed in ways that can be 
misinterpreted as psychotic symptoms (e.g. overvalued ideas and pseudo-hallucinations) 
but that instead are considered normal for the person’s subgroup.
• Symptom presentation of schizophrenia and other primary psychotic disorders may 
vary across cultures. For example, the content and form of hallucinations (e.g. visual 
hallucinations are more common in some cultural groups and in some countries) or 
delusions may be culturally derived, making it difficult to differentiate among culturally 
normal experiences, overvalued ideas, ideas of reference and transient psychosis. For 
instance, in several cultures (e.g. southern China, Latin America) it is common to expect 
the spirit of a deceased relative to visit the homes of living relatives soon after they die. 
Hearing, seeing or interacting with this spirit may be reported without notable pathological 
sequelae. Clarifying the cultural meaning of these experiences can aid in understanding 
the diagnostic significance of the symptom presentation.
• Cultural mismatch between the individual and the clinician may complicate the evaluation 
of schizophrenia and other primary psychotic disorders. Collateral information from 
family, community, religious or cultural reference groups may help clarify the diagnosis.
• Ethnic minority and migrant groups are more likely than those in the general population 
to receive a diagnosis of schizophrenia and other primary psychotic disorder. This may be 
due to misdiagnosis or to greater risk of psychosis resulting from migration traumas, social 
isolation, minority and acculturative stress, discrimination and victimization.
• Caution is advised when assessing psychotic symptoms through interpreters or in a second 
or third language because of the risk of misconstruing unfamiliar metaphors as delusions, 
and natural defensiveness as paranoia or emotional blunting.
Schizophrenia
Essential (required) features
• At least two of the following symptoms must be present (by the individual’s report or 
through observation by the clinician or other informants) most of the time for a period 
of 1 month or more. At least one of the qualifying symptoms should be from items 
a) to d) below:
a) persistent delusions (e.g. grandiose delusions, delusions of reference, persecutory 
delusions);
b) persistent hallucinations (most commonly auditory, although they may be in any 
sensory modality);
6A20
Schizophrenia and other primary psychotic disorders | Schizophrenia

163
Schizophrenia and other primary psychotic disorders
c) disorganized thinking (formal thought disorder) (e.g. tangentiality and loose 
associations, irrelevant speech, neologisms) – when severe, the person’s speech may 
be so incoherent as to be incomprehensible (“word salad”);
d) experiences of influence, passivity or control (i.e. the experience that one’s feelings, 
impulses, actions or thoughts are not generated by oneself, are being placed in one’s 
mind or withdrawn from one’s mind by others, or that one’s thoughts are being 
broadcast to others);
e) negative symptoms such as affective flattening, alogia or paucity of speech, avolition, 
asociality and anhedonia;
f) grossly disorganized behaviour that impedes goal-directed activity (e.g. behaviour 
that appears bizarre or purposeless, unpredictable or inappropriate emotional 
responses that interferes with the ability to organize behaviour);
g) psychomotor disturbances such as catatonic restlessness or agitation, posturing, 
waxy flexibility, negativism, mutism or stupor. Note: if the full syndrome of catatonia 
(p. 202) is present in the context of schizophrenia, the diagnosis of 6A40 Catatonia 
associated with another mental disorder should also be assigned.
• The symptoms are not a manifestation of another medical condition (e.g. a brain tumour), 
and are not due to the effects of a substance or medication (e.g. corticosteroids) on the central 
nervous system, including withdrawal effects (e.g. from alcohol).
Course specifiers for schizophrenia
The following specifiers should be applied to identify the course of schizophrenia, including 
whether the individual currently meets the diagnostic requirements of schizophrenia or is in 
partial or full remission. Course specifiers are also used to indicate whether the current episode 
is the first episode of schizophrenia, whether there have been multiple such episodes, or whether 
symptoms have been continuous over an extended period of time.
Schizophrenia, first episode
• The first episode specifier should be applied when the current or most recent episode is the first 
manifestation of schizophrenia meeting all diagnostic requirements in terms of symptoms 
and duration. If there has been a previous episode of schizophrenia or schizoaffective disorder, 
the multiple episodes specifier should be applied.
Schizophrenia, first episode, currently symptomatic
• All diagnostic requirements for schizophrenia in terms of symptoms and duration are 
currently met, or have been met within the past month.
• There have been no previous episodes of schizophrenia or schizoaffective disorder.
Note: if the duration of the episode is more than 1 year, the continuous specifier may be used 
instead, depending on the clinical situation.
6A20.00
6A20.0
Schizophrenia and other primary psychotic disorders | Schizophrenia

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Schizophrenia, first episode, in partial remission
• The full diagnostic requirements for schizophrenia have not been met within the past 
month, but some clinically significant symptoms remain, which may or may not be 
associated with functional impairment.
• There have been no previous episodes of schizophrenia or schizoaffective disorder.
Note: this category may also be used to designate the re-emergence of subthreshold symptoms 
of schizophrenia following an asymptomatic period in a person who has previously met the 
diagnostic requirements for schizophrenia.
Schizophrenia, first episode, in full remission
• The full diagnostic requirements for schizophrenia have not been met within the past 
month, and no clinically significant symptoms remain.
• There have been no previous episodes of schizophrenia or schizoaffective disorder.
Schizophrenia, first episode, unspecified
Schizophrenia, multiple episodes
• The multiple episodes specifier should be applied when there have been a minimum of two 
episodes meeting all diagnostic requirements of schizophrenia or schizoaffective disorder 
in terms of symptoms, with a period of partial or full remission between episodes lasting 
at least 3 months, and the current or most recent episode is schizophrenia. Note that the 
1-month duration requirement for the first episode does not necessarily need to be met 
for subsequent episodes. During the period of remission, the diagnostic requirements of 
schizophrenia are either only partially fulfilled or absent.
Schizophrenia, multiple episodes, currently symptomatic
• All symptom requirements for schizophrenia are currently met, or have been met within 
the past month. Note that the 1-month duration requirement for the first episode does not 
necessarily need to be met for subsequent episodes.
• There have been a minimum of two episodes of schizophrenia or a previous episode of 
schizoaffective disorder, with a period of partial or full remission between episodes lasting 
at least 3 months.
Schizophrenia, multiple episodes, in partial remission
• The full diagnostic requirements for schizophrenia have not been met within the past 
month, but some clinically significant symptoms remain, which may or may not be 
associated with functional impairment.
6A20.01
6A20.02
6A20.0Z
6A20.1
6A20.10
6A20.11
Schizophrenia and other primary psychotic disorders | Schizophrenia

165
Schizophrenia and other primary psychotic disorders
• There have been a minimum of two episodes of schizophrenia or a previous episode of 
schizoaffective disorder, with a period of partial or full remission between episodes lasting 
at least 3 months.
Note: this category may also be used to designate the re-emergence of subthreshold symptoms of 
schizophrenia following an asymptomatic period.
Schizophrenia, multiple episodes, in full remission
• The full diagnostic requirements for schizophrenia have not been met within the past 
month, and no clinically significant symptoms remain.
• There have been a minimum of two episodes of schizophrenia or a previous episode of 
schizoaffective disorder, with a period of partial or full remission between episodes lasting 
at least 3 months.
Schizophrenia, multiple episodes, unspecified
Schizophrenia, continuous
• The continuous specifier should be applied when symptoms fulfilling all diagnostic 
requirements of schizophrenia have been present for almost all of the course of the disorder 
during the person’s lifetime since its first onset, with periods of subthreshold symptoms 
being very brief relative to the overall course. In order to apply this specifier to a first 
episode, the duration of schizophrenia should be at least 1 year. In that case, the continuous 
specifier should be applied instead of the first episode specifier.
Schizophrenia, continuous, currently symptomatic
• All symptom requirements for schizophrenia are currently met, or have been met within 
the past month.
• Symptoms meeting the diagnostic requirements for schizophrenia have been present for 
almost all of the course of the disorder during the person’s lifetime since its first onset.
• Periods of partial or full remission have been very brief relative to the overall course, and 
none have lasted for 3 months or longer.
• To apply the continuous specifier to a first episode, symptoms meeting the diagnostic 
requirements for schizophrenia must have been present for at least 1 year.
Schizophrenia, continuous, in partial remission
• The full diagnostic requirements for schizophrenia, continuous were previously met but 
have not been met within the past month.
• Some clinically significant symptoms of schizophrenia remain, which may or may not be 
associated with functional impairment.
6A20.12
6A20.1Z
6A20.2
6A20.20
6A20.21
Schizophrenia and other primary psychotic disorders | Schizophrenia

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Note: this category may also be used to designate the re-emergence of subthreshold symptoms of 
schizophrenia following an asymptomatic period.
Schizophrenia, continuous, in full remission
• The full diagnostic requirements for schizophrenia, continuous were previously met but have 
not been met within the past month.
• No clinically significant symptoms of schizophrenia remain.
Schizophrenia, continuous, unspecified
Other specified episode of schizophrenia
Schizophrenia, episode unspecified
Additional clinical features
• The onset of schizophrenia may be acute, with serious disturbance apparent within a few 
days, or insidious, with a gradual development of signs and symptoms.
• A prodromal phase often precedes the onset of psychotic symptoms by weeks or months. 
The characteristic features of this phase often include loss of interest in work or social 
activities, neglect of personal appearance or hygiene, inversion of the sleep cycle and 
attenuated psychotic symptoms, accompanied by negative symptoms, anxiety/agitation or 
varying degrees of depressive symptoms.
• Between acute episodes there may be residual phases, which are similar phenomenologically 
to the prodromal phase.
• Schizophrenia is frequently associated with significant distress and significant impairment 
in personal, family, social, educational, occupational or other important areas of 
functioning. However, distress and psychosocial impairment are not requirements for a 
diagnosis of schizophrenia.
Boundary with normality (threshold)
• Psychotic-like symptoms or unusual subjective experiences may occur in the general 
population, but these are usually fleeting in nature and are not accompanied by other 
6A20.22 
6A20.2Z 
6A20.Y 
6A20.Z 
Schizophrenia and other primary psychotic disorders | Schizophrenia

167
Schizophrenia and other primary psychotic disorders
symptoms of schizophrenia or a deterioration in psychosocial functioning. In schizophrenia, 
multiple persistent symptoms are present, and are typically accompanied by impairment in 
cognitive functioning and other psychosocial problems.
Course features
• The course and onset of schizophrenia is variable. Some experience exacerbations and 
remission of symptoms periodically throughout their lives, others experience a gradual 
worsening of symptoms, and a smaller proportion experience complete remission of 
symptoms.
• Positive symptoms tend to diminish naturally over time, whereas negative symptoms often 
persist and are closely tied to a poorer prognosis. Cognitive symptoms also tend to be more 
persistent, and when present are associated with ongoing functional impairment.
• Early-onset schizophrenia is typically associated with a poorer prognosis whereas affective 
and social functioning are more likely to be preserved with later onset.
Developmental presentations
• Onset of fully symptomatic schizophrenia before puberty is extremely rare; when it occurs 
it is often preceded by a decline in social and academic functioning, odd behaviour, 
and a change in affect observable during the prodromal phase. Childhood onset is also 
associated with a greater prevalence of delays in social, language or motor development 
and co-occurring disorder of intellectual development or developmental learning disorder.
• In children and young adolescents, auditory hallucinations most commonly occur 
as a single voice commenting on or commanding behaviour whereas in adults such 
hallucinations are more typically experienced as multiple conversing voices.
• In children and adolescents, it may be challenging to differentiate delusions and 
hallucinations from more developmentally typical phenomena (e.g. a “monster” under 
the child’s bed, an imaginary friend), actual plausible life experiences (e.g. being teased 
or bullied at school), and irrational or magical thinking common in childhood (e.g. that 
thinking about something will make it happen).
• Among children with schizophrenia, negative symptoms, hallucinations and disorganized 
thinking – including loose associations, illogical thinking and paucity of speech – tend to 
be prominent features of the clinical presentation. Disorganized thinking and behaviour 
occur in a variety of disorders that are common in childhood (e.g. autism spectrum 
disorder, attention deficit hyperactivity disorder), which should be considered before 
attributing the symptoms to the much less common childhood schizophrenia.
Schizophrenia and other primary psychotic disorders | Schizophrenia

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Culture-related features
• Cultural factors may influence the onset, symptom pattern, course and outcome 
of schizophrenia. For example, among migrants and ethnic and cultural minority 
communities, living in areas with a low proportion of their own migrant, ethnic or cultural 
group (low “ethnic density”) is associated with higher rates of schizophrenia. In addition, 
etiological or course-related factors may be affected by culture at the level of the family 
(e.g. level of family support or style of family interaction, such as expressed emotion) or at 
the societal context (e.g. industrialization, urbanization). For example, the prevalence of 
schizophrenia is much higher in urban than rural settings.
• The risk of misdiagnosing the expression of distress as indicative of schizophrenia 
or another primary psychotic disorder may be increased among ethnic minority and 
immigrant groups, and in other situations in which the clinician is unfamiliar with 
culturally normative expressions of distress. These include situations involving spiritual 
or supernatural beliefs or resulting from migration trauma, social isolation, minority and 
acculturative stress, discrimination and victimization.
Sex- and/or gender-related features
• Schizophrenia is more prevalent among males.
• The age of onset of the first psychotic episode differs by gender, with a greater proportion 
of males experiencing onset in their early to mid-20s and females in their late 20s.
• Females with schizophrenia tend to report more positive symptoms that increase in severity 
over the course of their lives. Females also tend to have greater mood disturbance and a 
greater prevalence of subsequent or co-occurring mental disorders (e.g. schizoaffective 
disorder, depressive disorders).
• Females with schizophrenia are less likely to exhibit disorganized thinking, negative 
symptoms and social impairment.
Boundaries with other disorders and conditions (differential diagnosis)
Boundary with schizoaffective disorder
The diagnoses of schizophrenia and schizoaffective disorder are intended to apply to the current 
or most recent episode of the disorder. In other words, a previous diagnosis of schizoaffective 
disorder does not preclude a diagnosis of schizophrenia, and vice versa. In both schizophrenia and 
schizoaffective disorder, at least two the characteristic symptoms of schizophrenia are present most of 
the time for a period of 1 month or more. In schizoaffective disorder, the symptoms of schizophrenia 
are present concurrently with mood symptoms that meet the full diagnostic requirements of a 
mood episode and last for at least 1 month, and the onsets of the psychotic and mood symptoms 
are either simultaneous or occur within a few days of one another. In schizophrenia, co-occurring 
mood symptoms, if any, either do not persist for as long as 1 month or are not of sufficient severity 
Schizophrenia and other primary psychotic disorders | Schizophrenia

169
Schizophrenia and other primary psychotic disorders
to meet the requirements of a moderate or severe depressive episode, a manic episode or a mixed 
episode. (See mood episode descriptions, p. 212.) An episode that initially meets the diagnostic 
requirements for schizoaffective disorder in which only the mood symptoms remit, so that the 
duration of psychotic symptoms without mood symptoms is much longer than the duration of 
concurrent symptoms, may be best characterized as an episode of schizophrenia.
Boundary with acute and transient psychotic disorder
The psychotic symptoms in schizophrenia persist for at least 1 month in their full, florid form. 
In contrast, the symptoms in acute and transient psychotic disorder tend to fluctuate rapidly in 
intensity and type across time, such that the content and focus of delusions or hallucinations often 
shift, even on a daily basis. Such rapid shifts would be unusual in schizophrenia. Negative symptoms 
are often present in schizophrenia, but do not occur in acute and transient psychotic disorder. The 
duration of acute and transient psychotic disorder does not exceed 3 months, and most often lasts 
from a few days to 1 month, compared to a much longer typical course for schizophrenia. In cases 
that meet the diagnostic requirements for schizophrenia except that they have lasted less than the 
duration required for a diagnosis (i.e. 1 month) in the absence of a previous history of schizophrenia, 
a diagnosis of other specified primary psychotic disorder and not acute and transient psychotic 
disorder should be assigned.
Boundary with schizotypal disorder
Schizotypal disorder is characterized by an enduring pattern of unusual speech, perceptions, 
beliefs and behaviours that resemble attenuated forms of the defining symptoms of schizophrenia. 
Schizophrenia is differentiated from schizotypal disorder based entirely on the intensity of 
the symptoms: schizophrenia is diagnosed if the symptoms are sufficiently intense to meet 
diagnostic requirements.
Boundary with delusional disorder
Both schizophrenia and delusional disorder may be characterized by persistent delusions. If 
other features are present that meet the diagnostic requirements of schizophrenia (i.e. persistent 
hallucinations; disorganized thinking; experiences of influence, passivity or control; negative 
symptoms; disorganized or abnormal psychomotor behaviour), a diagnosis of schizophrenia 
should be made instead of a diagnosis of delusional disorder. However, hallucinations that are 
consistent with the content of the delusions and do not occur persistently (i.e. with regular 
frequency for 1 month or longer) are consistent with a diagnosis of delusional disorder rather than 
schizophrenia. Delusional disorder is generally characterized by relatively preserved personality 
and less deterioration and impairment in social and occupational functioning than schizophrenia, 
and individuals with delusional disorder tend to come to clinical attention for the first time at a later 
age. Individuals with symptom presentations consistent with delusional disorder (e.g. delusions and 
related, circumscribed hallucinations) but who have not met the minimum duration requirement 
of 3 months should not be assigned a diagnosis of schizophrenia, even though the combination 
of persistent delusions and related hallucinations technically meets diagnostic requirements for 
schizophrenia. Instead, a diagnosis of other specified primary psychotic disorder is more appropriate 
in such cases.
Boundary with moderate or severe depressive episodes in single episode 
depressive disorder, recurrent depressive disorder, and bipolar type I and bipolar 
type II disorders
Psychotic symptoms may also occur during moderate or severe depressive episodes. Delusions 
during depressive episodes may resemble delusions observed in schizophrenia, and are commonly 
persecutory or self-referential (e.g. being pursued by authorities because of imaginary crimes). 
Delusions of guilt (e.g. falsely blaming oneself for wrongdoing), poverty (e.g. being bankrupt) 
or impending disaster (perceived to have been brought on by the individual), as well as somatic 
delusions (e.g. of having contracted some serious disease) and nihilistic delusions (e.g. believing 
body organs do not exist), are also known to occur. Experiences of passivity, influence or control 
(e.g. thought insertion, thought withdrawal or thought broadcasting) may also occur in moderate or 
severe depressive episodes. Hallucinations are usually transient, and rarely occur in the absence of 
Schizophrenia and other primary psychotic disorders | Schizophrenia