Three types of thought alienation (see Figure 5.5; p. 68), in which the patient believes his thoughts are under the control of an external agency or that others are participating in this thinking, are included as first-rank symptoms. He may believe that external (alien) thoughts are being inserted into his mind by an external agency (thought insertion), or that his own thoughts are being withdrawn from his mind by an external agency (thought withdrawal). The third type of thought alienation is thought broadcasting, in which the patient believes that his thoughts are being ‘read’ by others, as if they were being broadcast.

The patient may experience the feeling that his free will has been removed and that an external agency is controlling his feelings (made feelings), impulses (made impulses) or actions (made actions or made acts). He may feel under a form of hypnosis.

A delusional perception involves a real perception (such as seeing a real object or hearing a real sound), which is followed by a delusional misinterpretation of that perception. For example, a patient suffering from chronic schizophrenia once saw that a door had been left slightly open (a real visual perception) and realized as a result that he was the King of Spain (a delusional misinterpretation of that perception).

Other ICD-10 symptoms

Besides Schneider’s first-rank symptoms, there are other symptoms of schizophrenia that are described by ICD-10 as having special importance for diagnosis. None of these is pathognomonic of schizophrenia. They include:

• Other persistent delusions. These include 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 planet).

• Persistent hallucinations. These are important in any modality, particularly when accompanied by fleeting or half-formed delusions without clear affective content, by persistent overvalued ideas or when occurring every day for weeks on end. An overvalued idea is an unreasonable and sustained intense preoccupation maintained with less than delusional intensity; the idea or belief is demonstrably false and is not normally held by others of the patient’s subculture. There is a marked emotional investment associated with overvalued ideas.

• Breaks or interpolations in the train of thought. These can result in incoherence or irrelevant speech. They can also cause neologisms – new words constructed by the patient or everyday words used in a special way.

• Catatonic behaviour. The symptoms of catatonia include stupor, in which the patient is unresponsive, akinetic, mute and fully conscious, and excitement; the patient may change between these two states. Other symptoms include: posturing, in which the patient adopts an inappropriate or bizarre bodily posture continuously for a substantial period of time; waxy flexibility (also known as cerea flexibilitas), in which the patient’s limbs can be ‘moulded’ into a position and remain fixed for long periods of time; and negativism, in which motiveless resistance occurs to instructions and to attempts to be moved.

• Negative symptoms. These typically occur in chronic schizophrenia. They include marked apathy, poverty of speech, lack of drive, slowness and blunting or incongruity of affect, and usually result in social withdrawal and lowered social performance. In identifying the presence of negative symptoms, other possible causes of such symptomatology (e.g. depression and antipsychotic medication) should first be excluded. The positive symptoms typically occur in acute schizophrenia, and have been discussed above; they include delusions, hallucinations and thought interference.

• Change in personal behaviour. This can be noted as 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.

Subtypes

ICD-10 distinguishes the following major types of schizophrenia.

Other classifications

The above ICD-10 subtypes can be argued to be unsatisfactory because many patients show clinical features characteristic of more than one. Two alternative types of classification are considered here.

Syndromal classifications

From a research viewpoint, the heterogeneous nature of schizophrenia limits the value of studies that group patients under this global label. One method of addressing such heterogeneity is to adopt a syndromal approach. There are a number of such approaches, one example being that of Liddle, who has classified the symptoms of schizophrenia into three syndromes:

• psychomotor poverty syndrome, characterized by poverty of speech, flatness of affect and decreased spontaneous movement

• disorganization syndrome, characterized by disorders of the form of thought and inappropriate affect

• reality distortion syndrome, characterized by the occurrence of delusions and hallucinations.

These syndromes can coexist in the same individual. Positron emission tomography (PET) regional cerebral blood flow (rCBF) studies have shown that each of these is associated with a specific pattern of perfusion in paralimbic and associated cerebral cortex and in related subcortical nuclei (Figure 8.1).

Figure 8.1 • Liddle’s classification.

• (a) Locus of maximal activation of the prefrontal cortex during the internal generation of words in normal subjects superimposed on the areas of decreased cortical blood flow associated with psychomotor poverty in schizophrenia. (b) Locus of maximal activity of the anterior cingulate cortex during performance of the Stroop test superimposed on the area of increased cortical blood flow associated with disorganization in schizophrenia. (c) Locus of maximal activation of the parahippocampal gyrus during the internal monitoring of eye movements superimposed on the area of increased medial temporal blood flow associated with reality distortion in schizophrenia.

A neurodevelopmental classification

On the basis of genetic, epidemiological, neuropathological, neuroimaging and gender difference studies, a neurodevelopmental classification has been put forward in which schizophrenia is subdivided into the following three groups:

• Congenital schizophrenia. The abnormality is present (although not necessarily recognizable) at birth, and may be caused by a genetic predisposition and/or an environmental insult such as maternal influenza, obstetric complications and early brain injury or infection. Patients are more likely to have minor physical abnormalities, to show abnormal personality or social impairment in childhood, to present to the psychiatric services early, to exhibit negative symptoms and to show morphological brain changes and cognitive impairment. They are also more likely to be male and to have a poor outcome.

• Adult-onset schizophrenia. These patients are more likely to exhibit positive symptoms, including Schneiderian first-rank symptoms, and mood (affective) symptoms. They may have a genetic predisposition to manifest symptomatology anywhere along a continuum from bipolar mood disorder (see Chapter 9), through schizoaffective disorder (see below) to acute schizophrenia (Figure 8.2).

• Late-onset schizophrenia. This is the group of late paraphrenia, discussed in Chapter 20, in which patients usually present after the age of 60 and have good premorbid functioning in the intellectual and occupational spheres. It is more common in females and is often associated with auditory and visual sensory deprivation, for example as a result of age-related hearing and

Figure 8.2 • The spectrum of ‘adult-onset’ psychotic disorders.

Clinical features and classification

• Schizophrenia can lead to changes in thinking, perception, affect and social functioning; cognitive functions are usually intact in the early stages.

• Schneider’s first-rank symptoms of schizophrenia include: auditory hallucinations; thought insertion, withdrawal or broadcasting; made feelings, impulses or actions; somatic passivity and delusional perception.

• Other important symptoms include: other persistent delusions; persistent hallucinations in any modality; persistent overvalued ideas; formal thought disorder; catatonic behaviour; social withdrawal.

• Positive symptoms typically occur in acute schizophrenia and include delusions, hallucinations and thought disorder; negative symptoms typically occur in chronic schizophrenia and include poverty of speech, blunting/incongruity of affect and social withdrawal.

• ICD-10 subtypes of schizophrenia include paranoid, hebephrenic, catatonic, simple and residual/chronic schizophrenia.

• Liddle’s three syndromes, which can coexist in the same individual, are psychomotor poverty, disorganization and reality distortion.

• A recent neurodevelopmental classification subdivides schizophrenia into the following three groups: congenital schizophrenia, adult-onset schizophrenia and late-onset schizophrenia.

visual impairment. It is sometimes related to a paranoid personality or to a mood disorder. Organic brain dysfunction is often found to be present.

Investigations

The investigations carried out in a patient presenting for the first time with schizophrenic symptomatology are those described in Chapter 5, and include:

• further information

• urea and electrolytes, full blood count, thyroid function tests, liver function tests

• a screen for illicit drugs, if psychoactive substance use is suspected as a cause

• vitamin B₁₂ and folate levels

• syphilitic serology

• electroencephalography (EEG) (the symptoms may be caused by complex partial seizures of the temporal lobe)

• computed tomography (CT) or magnetic resonance imaging (MRI) scan (if clinically indicated).

In the case of first presentation in the elderly, i.e. when the diagnosis being considered is paraphrenia (see Chapter 20), tests of hearing and vision should be carried out at an early stage, as sensory deprivation is an important cause in this age group.

Differential diagnosis

Organic disorders and psychoactive substance use disorders, described in Chapters 6 and 7, should be excluded before making a diagnosis of schizophrenia. A full physical examination and appropriate further investigations (see below) should be carried out, particularly with a first presentation, in order to do this.

Mood disorders (see Chapter 9) may present with symptoms similar to schizophrenia. Negative symptoms and the early stages of simple schizophrenia may be difficult to distinguish from depression. In such cases care should be taken to look for other symptoms of depression. Moreover, depression may itself be a symptom of schizophrenia, both in the acute phase and following an episode of schizophrenic illness (post-schizophrenic depression). Schneider’s first-rank symptoms can occur in mania. Therefore, one should look for other features of mania, particularly if there is no previous history of schizophrenia.

The onset of schizophrenia can lead to personality deterioration, which may simulate a personality disorder (see Chapter 15).

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