DSM-IV definition of this illness follows.This disorder consists of at least two of the following symptoms, for at least one month:
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).
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Catatonic schizophrenia a person is withdrawn, mute, negative and often assumes very unusual postures.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. These symptoms can be most devastating.