Positive & Negative Symptoms: Diagnosis & Classification of Schizophrenia (AQA A Level Psychology): Revision Note

How is schizophrenia diagnosed & classified?

How is schizophrenia diagnosed & classified?

• Schizophrenia is defined as a ‘chronic’ mental illness by the DSM-5 which means that it has been present in an individual for at least one year, is likely to be ongoing, significantly impedes daily life and requires constant medical attention

• The ICD-11 defines schizophrenia as a psychotic disorder, which means that it is characterised by severe and significant impairments in determining what is real and what is fantasy

• The DSM-IV classified schizophrenia according to whether at least one positive symptom was present in the patient (see below)

• The DSM-5 (the current edition) classifies schizophrenia according to whether the patient has experienced at least two of the positive or negative symptoms (delusions, hallucinations, disorganised speech)

• The ICD-10 classified schizophrenia according to whether two or more negative symptoms were present (see below)

• The ICD-11 classifies schizophrenia according to whether at least two positive or negative symptoms are present in the patient

• Both the ICD-11 and the DSM-5 state that psychotic symptoms should be present in the patient for at least one month for a diagnosis of schizophrenia to be made, with the DSM-5 requiring that these symptoms continue for up to 6 months

• Schizophrenia is not easy to diagnose, as it does not present as one set of clear-cut symptoms

Positive & negative symptoms of schizophrenia

• The terms 'positive' and 'negative' symptoms of schizophrenia do not refer to how helpful or harmful the symptoms are. Instead, they describe what is added or taken away from normal functioning

Positive symptoms

• Positive symptoms of schizophrenia include:

  • Hallucinations: these can take the form of:

    • voices talking to the patient, often critically and with negative intent;

    • seeing distortions in what is around them, e.g, in facial expressions

  • Delusions: these can take the form of:

    • misguided or irrational beliefs, e.g., the patient’s belief that they are Jesus

    • paranoia, e.g., that the CIA are spying on them

    • unfounded ideas as to their ability or even their body, e.g., that they have magic powers or that they are possessed by an evil spirit

• The positive symptoms of schizophrenia may cause alarm and distress to both the patient and other people, as they are active manifestations of the illness (although a schizophrenic patient is rarely a danger to anyone else)

Negative symptoms

• Negative symptoms of schizophrenia include:

  • Speech poverty/disorganisation: this can take the form of

    • alogia – not being able to take part in a conversation due to delayed responses, lack of vocabulary, and vagueness

    • producing speech which is incoherent, possibly nonsensical (e.g. inventing words) and which does not follow the rules of grammar

  • Avolition: this is a form of apathy in which the person takes no interest in life or in themselves and involves a complete lack of motivation to achieve even the simplest of tasks; they are likely to:

    • neglect personal hygiene

    • neglect their work or education

    • neglect activities that they usually find pleasurable

• The negative symptoms of schizophrenia are not active manifestations of the illness but more a withdrawal from life, which is not as immediately noticeable as the positive symptoms

  • This makes these symptoms harder to diagnose (additionally, negative symptoms are very similar to Major Depressive Disorder)

Issues & Debates

• Categorising schizophrenia into positive and negative symptoms is reductionist, as it simplifies a complex mental disorder into narrow classifications

  • This biological reductionism overlooks psychological, cognitive and social factors that may also contribute to the illness and its expression

  • It may also limit treatment options to mainly biological approaches (e.g. medication), reducing focus on holistic care

• Some symptoms (especially hallucinations and delusions) may be interpreted differently across cultures, leading to culture bias

  • What is considered a delusion in one culture might be a spiritual belief in another

  • This can lead to misdiagnosis or overdiagnosis in non-Western populations, reflecting a lack of cultural relativism in symptom classification