The symptom most people think about when hearing "Schizophrenia" is hallucination. However, ICD-10's entry for schizophrenia seems to list auditory hallucinations as just one of many possible symptoms.

In practice, are hallucinations a required symptom for a diagnosis of Schizophrenia, or can a diagnosis be made based on other symptoms?

  • $\begingroup$ I'm too lazy to walk down three floors and pick up the ICD-10 research criteria and DSM-5 right now, but usually the diagnostic criteria give a list of possible symptoms of which a certain number, but not all, must be met. I don't remember the IDC 10 criteria, but I know for a fact that the DSM-5 does not require the patient to have hallucinations for a diagnosis of Schizophrenia, because this has been asked before and I looked it up then. $\endgroup$
    – user3116
    Apr 27, 2014 at 8:56
  • $\begingroup$ If you desperately need the complete criteria, post a note and I'll look it up. $\endgroup$
    – user3116
    Apr 27, 2014 at 8:59
  • $\begingroup$ @what I linked to the ICD-10 entry in the question, though it is still unclear to me which (or how many of) the symptoms are required. Moreover, Schizophrenia seems to be a larger category with more subtypes under it, making the answer to my question more difficult to find. $\endgroup$
    – IQAndreas
    Apr 27, 2014 at 21:48

3 Answers 3


No – at least, they shouldn't be required. Wikipedia describes the DSM-5 as requiring "delusions, hallucinations, or disorganized speech". Delusions are distinct from hallucinations in that they aren't necessarily perceptual in a conventional sense, though both diverge a person's conscious experience from empirical reality. Disorganized speech is characteristic of disorganized / hebephrenic schizophrenia, regarding which Wikipedia states:

The most prominent features of disorganized schizophrenia are not delusions and hallucinations, as they are in paranoid schizophrenia,[5][6] although fragmentary delusions and hallucinations may be present.

This doesn't seem to be the only (partial) exception to the rule you ask about, and your source mentions it too: "Affective changes are prominent, delusions and hallucinations fleeting and fragmentary".


According to the DSM V, for the diagnosis of schizophrenia, the following is necessary:

two (or more) of the following, each present for a significant portion of time during a 1-month period (or less if successfully treated):
(1) Delusions
(2) Hallucinations
(3) Disorganized speech
(4) Grossly disorganized or catatonic behavior
(5) Negative symptoms, i.e., affective flattening, alogia, or avolition.

where one of the symptoms must be delusions, hallucinations, or disorganized speech. So, no, hallucinations do not need to be present.


No. Hallucinations are not necessarily present, although they use to be observed or reported. Hebephrenic schizophrenia does not have hallucinations as a main symptom, and simple schizophrenia doesn't have them at all. The criteria are very clear.

  • 1
    $\begingroup$ Your mention of simple schizophrenia is an interesting contribution, but not without controversy as a diagnosis. $\endgroup$ Apr 28, 2014 at 3:04
  • $\begingroup$ In fact, exactly as it happens with many other diagnosis. One must know they can be criticized too. $\endgroup$
    – Di Ana
    Apr 28, 2014 at 12:45
  • 1
    $\begingroup$ I'll rephrase: the controversy regarding the diagnostic validity of simple schizophrenia seems much greater than that surrounding other forms of schizophrenia. $\endgroup$ Apr 28, 2014 at 17:37

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