This disorder consists of at least two of the following symptoms, for at least one month:
(Only one symptom is required if delusions are bizarre or hallucinations consist of a voice keeping up a running commentary on the person's behavior or thoughts, or two or more voices conversing with each other.)
- Disorganized speech (e.g., frequent derailment or incoherence)
- Grossly disorganized or catatonic behavior
- Negative symptoms (e.g., affective flattening, alogia, avolition; see below)
For a significant portion of the time since the onset of the disturbance, one or more major areas of functioning such as work, interpersonal relations, or self-care are markedly below the level achieved prior to the onset (or when the onset is in childhood or adolescence, failure to achieve expected level of interpersonal, academic, or occupational achievement).
Schizoaffective Disorder and Mood Disorder With Psychotic Features have been considered as alternative explanations for the symptoms and have been ruled out.
The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.
If there is a history of Autistic Disorder or another Pervasive Developmental Disorder, the additional diagnosis of Schizophrenia is made only if prominent delusions or hallucinations are also present for at least a month (or less if successfully treated).
Positive and Negative Symptoms
There are two broad categories of schizophrenic symptoms: positive and negative. Postive symptoms are those that are 'above and beyond' normal levels of behavior. In contrast, negative symptoms may be characterized as 'less than' normal levels of behavior.
- Disorganized thinking
- Lack of drive or initiative
- Social withdrawal
- Emotional unresponsiveness
Different Types of Schizophrenia:
Paranoid schizophrenia: a person feels extremely suspicious, persecuted, grandiose, or experiences a combination of these emotions.
Disorganized schizophrenia: a person is often incoherent but may not have delusions.
Catatonic schizophrenia: a person is withdrawn, mute, negative and often assumes very unusual postures.
Residual schizophrenia: a person is no longer delusion or hallucinating, but has no motivation or interest in life.
Criteria summarized from:
American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders, fourth edition. Washington, DC: American Psychiatric Association.