Diagnosis of schizophrenia
Encyclopedia
The diagnosis of schizophrenia is based on criteria in either the American Psychiatric Association
's Diagnostic and Statistical Manual of Mental Disorders
, version DSM-IV-TR, or the World Health Organization
's International Statistical Classification of Diseases and Related Health Problems
, the ICD-10. These criteria use the self-reported experiences of the person and reported abnormalities in behavior, followed by a clinical assessment by a mental health professional
. Symptoms associated with schizophrenia occur along a continuum in the population and must reach a certain severity before a diagnosis is made. As of 2009 there is no objective test.
According to the revised fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), to be diagnosed with schizophrenia, three diagnostic criteria must be met:
If signs of disturbance are present for more than a month but less than six months, the diagnosis of schizophreniform disorder
is applied. Psychotic symptoms lasting less than a month may be diagnosed as brief psychotic disorder
, and various conditions may be classed as psychotic disorder not otherwise specified. Schizophrenia cannot be diagnosed if symptoms of mood disorder
are substantially present (although schizoaffective disorder
could be diagnosed), or if symptoms of pervasive developmental disorder
are present unless prominent delusions or hallucinations are also present, or if the symptoms are the direct physiological result of a general medical condition or a substance, such as abuse of a drug or medication.
contains five sub-classifications of schizophrenia, although the developers of DSM-5
are recommending they be dropped from the new classification:
The ICD-10
defines two additional subtypes:
, borderline personality disorder
, drug intoxication and drug-induced psychosis
. Delusions ("non-bizarre") are also present in delusional disorder
, and social withdrawal in social anxiety disorder
, avoidant personality disorder
and schizotypal personality disorder
. Schizophrenia is complicated with obsessive-compulsive disorder
(OCD) considerably more often than could be explained by pure chance, although it can be difficult to distinguish obsessions that occur in OCD from the delusions of schizophrenia.
A more general medical and neurological examination may be needed to rule out medical illnesses which may rarely produce psychotic schizophrenia-like symptoms, such as metabolic disturbance, systemic infection, syphilis
, HIV
infection, epilepsy
, and brain lesions. It may be necessary to rule out a delirium
, which can be distinguished by visual hallucinations, acute onset and fluctuating level of consciousness, and indicates an underlying medical illness. Investigations are not generally repeated for relapse unless there is a specific medical indication or possible adverse effects from antipsychotic medication.
"Schizophrenia" does not mean dissociative identity disorder
—formerly and still widely known as "multiple personalities"—despite the etymology
of the word (Greek σχίζω = "I split").
of schizophrenia, and its defining symptoms such as delusions and hallucinations, have been criticized.
There is an argument that the underlying issues would be better addressed as a spectrum of conditions or as individual dimensions along which everyone varies rather than by a diagnostic category based on an arbitrary cut-off between normal and ill. This approach appears consistent with research on schizotypy
, and with a relatively high prevalence of psychotic experiences, mostly non-distressing delusional beliefs, among the general public. In concordance with this observation, psychologist Edgar Jones, and psychiatrists Tony David
and Nassir Ghaemi, surveying the existing literature on delusions, pointed out that the consistency and completeness of the definition of delusion have been found wanting by many; delusions are neither necessarily fixed nor false, and need not involve the presence of incontrovertible evidence.
Nancy Andreasen, a leading figure in schizophrenia research, has criticized the current DSM-IV and ICD-10 criteria for sacrificing diagnostic validity
for the sake of artificially improving reliability
. She argues that overemphasis on psychosis in the diagnostic criteria, while improving diagnostic reliability, ignores more fundamental cognitive impairments that are harder to assess due to large variations in presentation. This view is supported by other psychiatrists. In the same vein, Ming Tsuang and colleagues argue that psychotic symptoms may be a common end-state in a variety of disorders, including schizophrenia, rather than a reflection of the specific etiology of schizophrenia, and warn that there is little basis for regarding DSM’s operational definition as the "true" construct of schizophrenia. Neuropsychologist Michael Foster Green went further in suggesting the presence of specific neurocognitive deficits may be used to construct phenotypes that are alternatives to those that are purely symptom-based. These deficits take the form of a reduction or impairment in basic psychological functions such as memory
, attention
, executive function and problem solving
.
The exclusion of affective components from the criteria for schizophrenia, despite their ubiquity in clinical settings, has also caused contention. This exclusion in the DSM has resulted in a "rather convoluted" separate disorder—schizoaffective disorder
. Citing poor interrater reliability, some psychiatrists have totally contested the concept of schizoaffective disorder as a separate entity. The categorical distinction between mood disorders and schizophrenia, known as the Kraepelinian dichotomy
, has also been challenged by data from genetic epidemiology.
American Psychiatric Association
The American Psychiatric Association is the main professional organization of psychiatrists and trainee psychiatrists in the United States, and the most influential worldwide. Its some 38,000 members are mainly American but some are international...
's Diagnostic and Statistical Manual of Mental Disorders
Diagnostic and Statistical Manual of Mental Disorders
The Diagnostic and Statistical Manual of Mental Disorders is published by the American Psychiatric Association and provides a common language and standard criteria for the classification of mental disorders...
, version DSM-IV-TR, or the World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
's International Statistical Classification of Diseases and Related Health Problems
ICD
The International Statistical Classification of Diseases and Related Health Problems is a medical classification that provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or disease...
, the ICD-10. These criteria use the self-reported experiences of the person and reported abnormalities in behavior, followed by a clinical assessment by a mental health professional
Mental health professional
A mental health professional is a health care practitioner who offers services for the purpose of improving an individual's mental health or to treat mental illness. This broad category includes psychiatrists, clinical psychologists, clinical social workers, psychiatric nurses, mental health...
. Symptoms associated with schizophrenia occur along a continuum in the population and must reach a certain severity before a diagnosis is made. As of 2009 there is no objective test.
Criteria
The ICD-10 criteria are typically used in European countries, while the DSM-IV-TR criteria are used in the United States and the rest of the world, and are prevailing in research studies. The ICD-10 criteria put more emphasis on Schneiderian first-rank symptoms. In practice, agreement between the two systems is high.According to the revised fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), to be diagnosed with schizophrenia, three diagnostic criteria must be met:
- Characteristic symptoms: Two or more of the following, each present for much of the time during a one-month period (or less, if symptoms remitted with treatment).
- DelusionDelusionA delusion is a false belief held with absolute conviction despite superior evidence. Unlike hallucinations, delusions are always pathological...
s - HallucinationHallucinationA hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid,...
s - Disorganized speech, which is a manifestation of formal thought disorderThought disorderIn psychiatry, thought disorder or formal thought disorder is a term used to describe incomprehensible language, either speech or writing, that is presumed to reflect thinking. There are different types...
- Grossly disorganized behavior (e.g. dressing inappropriately, crying frequently) or catatonicCatatoniaCatatonia is a state of neurogenic motor immobility, and behavioral abnormality manifested by stupor. It was first described in 1874: Die Katatonie oder das Spannungsirresein ....
behavior - Negative symptoms: Blunted affectBlunted affectBlunted affect is the scientific term describing a lack of emotional reactivity on the part of an individual. It is manifest as a failure to express feelings either verbally or non-verbally, even when talking about issues that would normally be expected to engage the emotions...
(lack or decline in emotional response), alogiaAlogiaIn psychology, alogia , or poverty of speech, is a general lack of additional, unprompted content seen in normal speech. As a symptom, it is commonly seen in patients suffering from schizophrenia, and is considered as a negative symptom...
(lack or decline in speech), or avolitionAvolitionAvolition is a psychological state characterized by general lack of drive, or motivation to pursue meaningful goals. A person may show little participation in work or have little interest in socializing. They may sit still for long periods of time...
(lack or decline in motivation)
- If the delusions are judged to be bizarre, or hallucinations consist of hearing one voice participating in a running commentary of the patient's actions or of hearing two or more voices conversing with each other, only that symptom is required above. The speech disorganization criterion is only met if it is severe enough to substantially impair communication.
- Delusion
- Social or occupational dysfunction: For a significant portion of the time since the onset of the disturbance, one or more major areas of functioning such as work, interpersonal relations, or self-care, are markedly below the level achieved prior to the onset.
- Significant duration: Continuous signs of the disturbance persist for at least six months. This six-month period must include at least one month of symptoms (or less, if symptoms remitted with treatment).
If signs of disturbance are present for more than a month but less than six months, the diagnosis of schizophreniform disorder
Schizophreniform disorder
Schizophreniform disorder is a mental disorder diagnosed when symptoms of schizophrenia are present for a significant portion of the time within a one-month period, but signs of disruption are not present for the full six months required for the diagnosis of schizophrenia.The symptoms of both...
is applied. Psychotic symptoms lasting less than a month may be diagnosed as brief psychotic disorder
Brief psychotic disorder
Brief psychotic disorder is a period of psychosis whose duration is generally shorter, non re-occurring, and not better accounted for by another condition....
, and various conditions may be classed as psychotic disorder not otherwise specified. Schizophrenia cannot be diagnosed if symptoms of mood disorder
Mood disorder
Mood disorder is the term designating a group of diagnoses in the Diagnostic and Statistical Manual of Mental Disorders classification system where a disturbance in the person's mood is hypothesized to be the main underlying feature...
are substantially present (although schizoaffective disorder
Schizoaffective disorder
Schizoaffective disorder is a psychiatric diagnosis that describes a mental disorder characterized by recurring episodes of elevated or depressed mood, or of simultaneously elevated and depressed mood, that alternate with, or occur together with, distortions in perception.Schizoaffective disorder...
could be diagnosed), or if symptoms of pervasive developmental disorder
Pervasive developmental disorder
Pervasive developmental disorders is a diagnostic category refers to a group of disorders characterized by delays or impairments in communication, social behaviors, and cognitive development.Pervasive developmental disorders include Autism, Asperger's syndrome, Rett's syndrome, Childhood...
are present unless prominent delusions or hallucinations are also present, or if the symptoms are the direct physiological result of a general medical condition or a substance, such as abuse of a drug or medication.
Subtypes
The DSM-IV-TRDiagnostic and Statistical Manual of Mental Disorders
The Diagnostic and Statistical Manual of Mental Disorders is published by the American Psychiatric Association and provides a common language and standard criteria for the classification of mental disorders...
contains five sub-classifications of schizophrenia, although the developers of DSM-5
DSM-5
The next edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders , commonly called DSM-5 , is currently in consultation, planning and preparation...
are recommending they be dropped from the new classification:
- Paranoid type: Where delusions and hallucinations are present but thought disorder, disorganized behavior, and affective flattening are absent. (DSM code 295.3/ICD code F20.0)
- Disorganized typeDisorganized schizophreniaDisorganized schizophrenia, also known as hebephrenia is a subtype of schizophrenia as defined in the Diagnostic and Statistical Manual of Mental Disorders, DSM-IV code 295.10....
: Named hebephrenic schizophrenia in the ICD. Where thought disorder and flat affectBlunted affectBlunted affect is the scientific term describing a lack of emotional reactivity on the part of an individual. It is manifest as a failure to express feelings either verbally or non-verbally, even when talking about issues that would normally be expected to engage the emotions...
are present together. (DSM code 295.1/ICD code F20.1) - Catatonic typeCatatoniaCatatonia is a state of neurogenic motor immobility, and behavioral abnormality manifested by stupor. It was first described in 1874: Die Katatonie oder das Spannungsirresein ....
: The subject may be almost immobile or exhibit agitated, purposeless movement. Symptoms can include catatonic stupor and waxy flexibilityWaxy flexibilityWaxy flexibility is a psychomotor symptom of catatonic schizophrenia which leads to a decreased response to stimuli and a tendency to remain in an immobile posture....
. (DSM code 295.2/ICD code F20.2) - Undifferentiated type: Psychotic symptoms are present but the criteria for paranoid, disorganized, or catatonic types have not been met. (DSM code 295.9/ICD code F20.3)
- Residual type: Where positive symptoms are present at a low intensity only. (DSM code 295.6/ICD code F20.5)
The ICD-10
ICD
The International Statistical Classification of Diseases and Related Health Problems is a medical classification that provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or disease...
defines two additional subtypes:
- Post-schizophrenic depression: A depressive episode arising in the aftermath of a schizophrenic illness where some low-level schizophrenic symptoms may still be present. (ICD code F20.4)
- Simple schizophrenia: Insidious and progressive development of prominent negative symptoms with no history of psychotic episodes. (ICD code F20.6)
Differential
Psychotic symptoms may be present in several other mental disorders, including bipolar disorderBipolar disorder
Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
, borderline personality disorder
Borderline personality disorder
Borderline personality disorder is a personality disorder described as a prolonged disturbance of personality function in a person , characterized by depth and variability of moods.The disorder typically involves unusual levels of instability in mood; black and white thinking, or splitting; the...
, drug intoxication and drug-induced psychosis
Substance-induced psychosis
Substance-induced psychosis is a form of substance-related disorder where psychosis can be attributed to substance use.Various psychoactive substances have been implicated in causing, exacerbating, and/or precipitating psychotic states and/or disorders in users...
. Delusions ("non-bizarre") are also present in delusional disorder
Delusional disorder
Delusional disorder is an uncommon psychiatric condition in which patients present with circumscribed symptoms of non-bizarre delusions, but with the absence of prominent hallucinations and no thought disorder, mood disorder, or significant flattening of affect...
, and social withdrawal in social anxiety disorder
Social anxiety disorder
Social anxiety disorder , also known as social phobia, is an anxiety disorder characterized by intense fear in social situations causing considerable distress and impaired ability to function in at least some parts of daily life...
, avoidant personality disorder
Avoidant personality disorder
Avoidant personality disorder is a personality disorder recognized in the Diagnostic and Statistical Manual of Mental Disorders handbook in a person characterized by a pervasive pattern of social inhibition, feelings of inadequacy, extreme sensitivity to negative evaluation, and avoidance of...
and schizotypal personality disorder
Schizotypal personality disorder
Schizotypal personality disorder, or simply schizotypal disorder, is a personality disorder that is characterized by a need for social isolation, anxiety in social situations, odd behavior and thinking, and often unconventional beliefs.-Genetic:...
. Schizophrenia is complicated with obsessive-compulsive disorder
Obsessive-compulsive disorder
Obsessive–compulsive disorder is an anxiety disorder characterized by intrusive thoughts that produce uneasiness, apprehension, fear, or worry, by repetitive behaviors aimed at reducing the associated anxiety, or by a combination of such obsessions and compulsions...
(OCD) considerably more often than could be explained by pure chance, although it can be difficult to distinguish obsessions that occur in OCD from the delusions of schizophrenia.
A more general medical and neurological examination may be needed to rule out medical illnesses which may rarely produce psychotic schizophrenia-like symptoms, such as metabolic disturbance, systemic infection, syphilis
Syphilis
Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...
, HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
infection, epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
, and brain lesions. It may be necessary to rule out a delirium
Delirium
Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...
, which can be distinguished by visual hallucinations, acute onset and fluctuating level of consciousness, and indicates an underlying medical illness. Investigations are not generally repeated for relapse unless there is a specific medical indication or possible adverse effects from antipsychotic medication.
"Schizophrenia" does not mean dissociative identity disorder
Dissociative identity disorder
Dissociative identity disorder is a psychiatric diagnosis and describes a condition in which a person displays multiple distinct identities , each with its own pattern of perceiving and interacting with the environment....
—formerly and still widely known as "multiple personalities"—despite the etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
of the word (Greek σχίζω = "I split").
Controversies
The scientific validityValidity (statistics)
In science and statistics, validity has no single agreed definition but generally refers to the extent to which a concept, conclusion or measurement is well-founded and corresponds accurately to the real world. The word "valid" is derived from the Latin validus, meaning strong...
of schizophrenia, and its defining symptoms such as delusions and hallucinations, have been criticized.
There is an argument that the underlying issues would be better addressed as a spectrum of conditions or as individual dimensions along which everyone varies rather than by a diagnostic category based on an arbitrary cut-off between normal and ill. This approach appears consistent with research on schizotypy
Schizotypy
Schizotypy is a psychological concept which describes a continuum of personality characteristics and experiences ranging from normal dissociative, imaginative states to more extreme states related to psychosis and in particular, schizophrenia...
, and with a relatively high prevalence of psychotic experiences, mostly non-distressing delusional beliefs, among the general public. In concordance with this observation, psychologist Edgar Jones, and psychiatrists Tony David
Anthony David
Anthony David is Professor of Cognitive neuropsychiatry at the Institute of Psychiatry, part of King's College London.Professor David studied medicine at the University of Glasgow, subsequently training in neurology, then psychiatry...
and Nassir Ghaemi, surveying the existing literature on delusions, pointed out that the consistency and completeness of the definition of delusion have been found wanting by many; delusions are neither necessarily fixed nor false, and need not involve the presence of incontrovertible evidence.
Nancy Andreasen, a leading figure in schizophrenia research, has criticized the current DSM-IV and ICD-10 criteria for sacrificing diagnostic validity
Validity (statistics)
In science and statistics, validity has no single agreed definition but generally refers to the extent to which a concept, conclusion or measurement is well-founded and corresponds accurately to the real world. The word "valid" is derived from the Latin validus, meaning strong...
for the sake of artificially improving reliability
Reliability (statistics)
In statistics, reliability is the consistency of a set of measurements or of a measuring instrument, often used to describe a test. Reliability is inversely related to random error.-Types:There are several general classes of reliability estimates:...
. She argues that overemphasis on psychosis in the diagnostic criteria, while improving diagnostic reliability, ignores more fundamental cognitive impairments that are harder to assess due to large variations in presentation. This view is supported by other psychiatrists. In the same vein, Ming Tsuang and colleagues argue that psychotic symptoms may be a common end-state in a variety of disorders, including schizophrenia, rather than a reflection of the specific etiology of schizophrenia, and warn that there is little basis for regarding DSM’s operational definition as the "true" construct of schizophrenia. Neuropsychologist Michael Foster Green went further in suggesting the presence of specific neurocognitive deficits may be used to construct phenotypes that are alternatives to those that are purely symptom-based. These deficits take the form of a reduction or impairment in basic psychological functions such as memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
, attention
Attention
Attention is the cognitive process of paying attention to one aspect of the environment while ignoring others. Attention is one of the most intensely studied topics within psychology and cognitive neuroscience....
, executive function and problem solving
Problem solving
Problem solving is a mental process and is part of the larger problem process that includes problem finding and problem shaping. Consideredthe most complex of all intellectual functions, problem solving has been defined as higher-order cognitive process that requires the modulation and control of...
.
The exclusion of affective components from the criteria for schizophrenia, despite their ubiquity in clinical settings, has also caused contention. This exclusion in the DSM has resulted in a "rather convoluted" separate disorder—schizoaffective disorder
Schizoaffective disorder
Schizoaffective disorder is a psychiatric diagnosis that describes a mental disorder characterized by recurring episodes of elevated or depressed mood, or of simultaneously elevated and depressed mood, that alternate with, or occur together with, distortions in perception.Schizoaffective disorder...
. Citing poor interrater reliability, some psychiatrists have totally contested the concept of schizoaffective disorder as a separate entity. The categorical distinction between mood disorders and schizophrenia, known as the Kraepelinian dichotomy
Kraepelinian dichotomy
The Kraepelinian dichotomy refers to the division of the major endogenous psychoses into the disease concepts of dementia praecox, which was reformulated as schizophrenia by Eugen Bleuler in 1911, and manic-depressive psychosis, which has now been reconceived as bipolar disorder. This division was...
, has also been challenged by data from genetic epidemiology.