Positive & Negative Symptoms: Diagnosis & Classification of Schizophrenia

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 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; seeing things that are not there
  • 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 own ability or even their body (e.g. that they have magic powers; 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)

Hallucinations are a cause of huge distress to the schizophrenic person.

• 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, 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; they are likely to neglect personal hygiene, neglect their work or education, neglect activities that they usually find pleasurable; in short it involves a complete lack of motivation to achieve even the simplest of tasks
• 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, making these symptoms harder to diagnose (additionally, negative symptoms are very similar to Major Depressive Disorder)

Avolition can involve a total lack of motivation and energy.

Link to Issues & Debates:

The classification of schizophrenia can be analysed using the reductionism/holism debate as it may be limiting to attempt to fit people into neat categories according to their symptomatology . Treating schizophrenia on a case-by-case basis, using a holistic approach would ultimately be a much better approach to take - but it is expensive and time-consuming which pretty much rules it out for most health settings.