Mental health professionals have to confirm a diagnosis of schizophrenia by a process of exclusion. This means that all other possible disorders must first be ruled out. Once the diagnosis of schizophrenia is confirmed, the specialist usually further classifies the disorder as one of the specific subtypes of schizophrenia.

Diagnosis of Schizophrenia

The presence of psychosis implies that a person may be schizophrenic, but a diagnosis of schizophrenia cannot be based on psychosis alone. Other conditions may cause psychotic episodes, including:

  • Bipolar disorder
  • Depression
  • Brain injury or infection
  • Substance abuse
  • Dementia
  • Delirium.

Psychotic behavior may also be a side effect of certain medications.

A diagnosis of schizophrenia begins by ruling out other causes of psychosis. Blood tests may reveal thyroid hormone imbalances or an adverse reaction to drugs. Some hypertension and anti-heart arrhythmia medications can cause hallucinations, and cocaine and amphetamine use can both produce psychotic symptoms.

A detailed medical history is gathered from the patient, family members, friends, teachers, employers or colleagues. Schizophrenia may develop quickly or over a period of years.

Most people with schizophrenia go through a “premorbid” period. This is the time period prior to the actual onset of schizophrenia, marked by increased social isolation, a slow deterioration in social skills and bizarre behavior.

Schizophrenia Diagnosis Requirements

A diagnosis of schizophrenia is based on specific symptoms. The patient has experienced at least two of the following symptoms for at least six months:

  • Blunted emotions
  • Catatonic behavior
  • Delusions
  • Disorganized speech
  • Hallucinations
  • Impaired social functioning
  • Loss of motivation.

Types of Schizophrenia

During diagnosis, symptoms are classified according to the different types of schizophrenia: catatonic schizophrenia, disorganized schizophrenia, paranoid schizophrenia, undifferentiated schizophrenia and residual schizophrenia.

Catatonic Schizophrenia

Among the different types of schizophrenia, catatonic schizophrenia displays perhaps the widest range of behavioral symptoms. Catatonic schizophrenia is considered if the individual displays any two of the following symptoms:

  • Bizarre behavior
  • Bizarre mannerisms
  • Bizarre posture
  • Echolalia, or parroting of words
  • Echopraxia, or mimicking movements
  • Grimacing
  • Hyperactivity with no identifiable purpose
  • Muscle immobility
  • Mutism
  • Negativism
  • Stupor.

Disorganized Schizophrenia

Disorganized schizophrenia is characterized by disorganized speech and behavior. Disorganized schizophrenia also causes flat or inappropriate emotions. Although people with disorganized schizophrenia may display some of the symptoms of catatonic schizophrenia, the condition does not fulfill all of the criteria for a catatonic schizophrenia diagnosis.

Paranoid Schizophrenia

Paranoid schizophrenia causes delusions and auditory hallucinations that result in paranoia and anxiety. Paranoid schizophrenia is considered one of the most treatable types of schizophrenia. It generally causes less social disability than other types of schizophrenia.

Undifferentiated Schizophrenia

Undifferentiated schizophrenia covers any schizophrenia diagnosis where symptoms do not meet the criteria for paranoid, catatonic or disorganized schizophrenia. Undifferentiated schizophrenia is the most common of all types of schizophrenia.

Residual Schizophrenia

Residual schizophrenia is diagnosed in individuals whose symptoms have abated, although they once met the criteria for one of the types of schizophrenia. Although no longer exhibiting severe symptoms, the person continues to undergo treatment for schizophrenia.

A residual schizophrenia diagnosis is often based on a display of “negative” symptoms such as blunted emotions, lack of motivation and reduced speech and milder versions of symptoms of other types of schizophrenia.


Fauci, A., Braunwald, E., Isselbacher, K., Wilson, J., Martin, J., Kasper, D., Hauser, S.

 Posted on : June 14, 2014