Paranoid-typeschizophrenia is characterized by delusions and auditory hallucinations (hearing voices that don't exist) but relatively normal intellectual functioning and expression of emotions. The delusions can often be about being persecuted by a person or an organization, or feeling harassed or treated unfairly. People with paranoid-type schizophrenia can exhibit anger, aloofness, anxiety, and can be argumentative.
Disorganized-type schizophrenia is characterized by speech and behavior that are disorganized or difficult to understand, and flattening or inappropriate emotions. People with disorganized-type schizophrenia may laugh inappropriately for no apparent reason, make illogical statements, or seem preoccupied with their own thoughts or perceptions. Their disorganized behavior may disrupt normal activities, such as showering, dressing, and preparing meals.
Undifferentiated-type schizophrenia is characterized by some symptoms seen in all of the above types, but not enough of any one of them to define it as another particular type of schizophrenia.
Residual-type schizophrenia is characterized by a past history of at least one episode of schizophrenia, but the person currently has no "positive" symptoms (such as delusions, hallucinations, disorganized speech, or behavior). It may represent a transition between a full-blown episode and complete remission, or it may continue for years without any further psychotic episodes.