Classification of schizophrenia

Classification of schizophrenia

Schizophrenia does not have a single defining characteristic - it is a cluster of symptoms some of which appear to be unrelated.

There are two major systems for classification of mental disorders, they are the World Health Organisation’s International Classification of Disease edition 10 (ICD-10) and the American Psychiatric Association’s Diagnostic and Statistical Manual edition 5 (DSM-5).

Both of these systems differ slightly.

Schizophrenia

Affects thoughts and processes and the ability to determine reality.

Degrees of severity varies between sufferers.

Schizophrenia may be a group of disorders, with different causes and explanations.

ICD-10

Symptoms should be present for most of the time during an episode of psychotic illness (lasting at least 1 month).

Symptoms include:

• Thought echo

• Delusions of control, influence or passivity

• Hallucinatory voices or other types of hallucinations (persistent)

• Persistent delusions that are culturally inappropriate or completely impossible

• Neologisms, breaks or interpolations in the train of thought, resulting in incoherence or irrelevant spech

• “Negative” symptoms, such as marked apathy, paucity of speech and blunting of emotional responses

(It must be clear these are not due to depression or to neuroleptic medication)

DSM-5

To meet the criteria for diagnosis of schizophrenia, the patient must have experienced at least two of the following:

• Delusions

• Hallucinations

• Disorganised speech

• Disorganised or catatonic behaviour

• Negative symptoms

At least one of the symptoms must be the presence of delusions, hallucinations, or disorganised speech.

Continuous signs of the disturbance must persist for at least 6 months - in which the patient must experience at least one month of active symptoms.

With social or occupations deterioration problems occurring over a significant amount of time. These problems must not be attributable to another condition.

Positive symptoms

Atypical symptoms experienced in addition to normal experiences.

• Hallucinations:

Unusual sensory experiences.

E.g. voices talking to them or commenting of the sufferer (often critical).

Can be experienced in relation to any sense, like distorted faces that are not there.

• Delusions:

Also known as paranoia, delusions are irrational beliefs that can take a range of forms.

Common delusions involve being an important historical, political or religious figure.

They commonly involve being prosecuted, perhaps by the government or aliens or having superpowers.

Another class of delusions concerns the body, believing that they or part of them is under external control

Negative symptoms

Atypical experiences that represent the loss of a usual experience, such as clear thinking or ‘normal’ levels of motivation.

• Avolition:

Losing the will to perform the behaviours necessary to accomplish purposeful acts, like activities of daily life/goals/desires.

Can be described as finding it difficult to begin or keep up with goal-directed activity (actions performed to achieve a result).

Often have very reduced motivation and results in lower activity levels, sometimes called ‘apathy’.

Adreason (1982) identified 3 identifying signs of avolition - poor hygiene and grooming / lack of persistence in work or education/ lack of energy.

• Speech poverty (Alogia):

Schizophrenia is characterised by changes in patterns of speech.

Speech poverty refers to minimal verbal communication that lacks the additional unprompted content characteristic of normal speech.

The ICD-10 recognises speech poverty as a negative symptom because it is a reduction in the quality and amount of speech.

Sometimes accompanied by a delay in the sufferer’s verbal responses during conversation.

A characteristic is the tendency to speack only when prompted and with limited answers.

Reliability and validity