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It is a disorder characterized by apathy, avolition, and affective blunting. These patients have alterations in thoughts, perceptions, mood, and behavior. Many schizophrenics display delusions, hallucinations and misinterpretations of reality.

DSM-IV Diagnostic Criteria

Two or more of the following symptoms present for one month



Disorganized speech

Grossly disorganized or catatonic behavior schizophrenia, psychosis, scizophrenia

Negative symptoms, i.e., affective flattening, alogia, avolition

Decline in social and/or occupational functioning since the onset of

Continuous signs of illness for psychosis, psychotic at least six months with

Schizoaffective disorder and mood disorder with psychotic features have been

The disturbance is not due to substance abuse or medical condition

If history of autistic disorder or pervasive developmental disorder is present, schizophrenia may

Clinical Features

No sign or symptom is pathognomonic.

Prior history of schizotypal or schizoid personality traits or disorder are often present.

Depressive symptoms may be present, but duration of these symptoms has been brief compared to duration of the psychotic symptoms.

Many symptoms are categorized as either positive or negative.

  1. Positive Symptoms:
    1. Hallucinations are most commonly auditory or visual, but can occur in any sensory modality.
    2. Delusions
    3. Disorganized behavior
    4. Thought disorder characterized by loose associations, tangentiality, incoherent thoughts, neologisms, thought blocking, thought insertion, thought broadcasting, and ideas of reference.
  3. Negative Symptoms:
    1. Poverty of speech or poverty of thought content
    2. Anhedonia
    3. Flat affect
    4. Loss of motivation (avolition)
    5. Attentional deficits
The presence of tactile, olfactory or gustatory hallucinations may indicate an organic etiology such as complex partial seizures.

Sensorium and memory are intact unless the patient is too psychotic to engage in testing.

Insight and judgment frequently impaired.


  1. Lifetime prevalence of is one percent.
  2. Onset of psychosis usually occurs in late teens or early twenties.
  3. Males and females are equally affected, but mean age of onset is approximately six years later in females, and females frequently have a milder course of illness.
  4. The suicide rate is ten times that of normals, and the rate is close to the rate that occurs in depressive illnesses.
  5. More than 75% of patients are smokers, and an increased incidence of substance abuse has been found (especially alcohol, cocaine, and marijuana.)
  6. Most do not return to baseline functioning, and most patients follow a chronic downward course, but some have a gradual improvement with a decrease in positive symptoms and increased functioning. Very few have a complete recovery.
  1. Paranoid Type
    1. Characterized by a preoccupation with one or more delusions or frequent auditory hallucinations.
    2. No prominent disorganization of speech, disorganized or catatonic behavior, or flat or inappropriate affect.
  3. Disorganized Type : Characterized by prominent disorganized speech, disorganized behavior, and flat or inappropriate affect.
  4. Catatonic Type : Characterized by at Least Two of the Following:
    1. Motoric immobility
    2. Excessive motor activity
    3. Extreme negativism or mutism
    4. Peculiar voluntary movements such as bizarre posturing
    5. Echolalia or echopraxia
  6. Undifferentiated Type : Meets criteria, but can not be characterized as paranoid, disorganized or catatonic type.
  7. Residual Type : Characterized by absence of prominent delusions, disorganized speech and grossly disorganized or catatonic behavior and continued negative symptoms or two or more attenuated positive symptoms.
Differential Diagnosis
  1. Psychotic Disorder Due to a General Medical Condition, Delirium, or Dementia.
  2. Substance Induced Psychotic Disorder: Amphetamines and cocaine frequently cause hallucinations, paranoia, or delusions. Phencyclidine (PCP) may lead to both positive and negative symptoms.
  3. Schizoaffective Disorder: Moods symptoms are present for a significant portion of the illness. In duration of mood symptoms is brief compared to the entire duration of the illness.
  4. Mood Disorder with Psychotic Features
    1. Psychotic symptoms occur only during major mood disturbance (mania or major depression).
    2. Disturbances of mood frequent in all phases.
  5. Delusional Disorder: Non-bizarre delusions in absence of