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