Schizophrenia: Diagnosis and Types

Schizophrenia diagnosis is an exercise in exclusion: Before a person is diagnosed as schizophrenic all other possible disorders must be ruled out. Once a schizophrenia diagnosis is made, the disorder is classified according to the different types of schizophrenia.

Schizophrenia Diagnosis

The presence of psychosis implies a person may be schizophrenic, but schizophrenia diagnosis cannot be made based on the presence of psychosis alone. Many other conditions may mimic schizophrenia, including:

bipolar disorder
depression
head trauma
illicit drug abuse
medication side effects
thyroid hormone symptoms
vitamin deficiencies
other physical/mental symptoms.

A schizophrenia diagnosis begins by ruling out potential causes of psychosis. The doctor will order blood tests, which may reveal the presence of irregular thyroid hormones, or adverse reactions to illicit or prescription drugs. Some hypertension and anti-heart arrhythmia medications can cause hallucinations, and the illicit drugs cocaine and amphetamine both produce effects that mimic schizophrenia symptoms.

A schizophrenia diagnosis begins by ruling out potential causes of psychosis.

The doctor will attempt to gather a detailed medical history and history of schizophrenic behavior from the patient, family members, friends, teachers, employers, or other sources. Schizophrenia may develop quickly, or symptoms may develop over a period of years.

Most schizophrenics go through a "premorbid" period: a time period prior to actual schizophrenia onset. The premorbid period may be marked by increased social isolation, a slow deterioration in social skills, and bizarre behavior. Understanding how symptoms developed helps medical professionals make an accurate schizophrenia diagnosis.

Criteria for Schizophrenia Diagnosis

A schizophrenia diagnosis is made when specific criteria are met. The potential schizophrenic must have experienced at least two of the following for a period of at least six months:

"blunted" emotions/affect
catatonic behavior
delusions
disorganized speech
hallucinations
impaired social functioning
loss of motivation.

If these symptoms cannot be explained by other conditions, the patient is considered schizophrenic. A schizophrenia diagnosis should be made by a qualified psychiatrist.

Types of Schizophrenia

Once a schizophrenia diagnosis is made, the schizophrenic's condition is classified according to the established schizophrenia categories: catatonic schizophrenia, disorganized shizophrenia, paranoid schizophrenia, undifferentiated schizophrenia, residual schizophrenia.

Catatonic Schizophrenia: Of all the types of schizophrenia, catatonic schizophrenia displays perhaps the widest range of behavioral symptoms. A schizophrenic is considered catatonic if he or she displays any two of the following symptoms:

bizarre behavior
bizarre mannerisms
bizarre posture
echolalia (parroting of words)
echopraxia (mimicking movements)
facial grimacing
hyperactivity with no identifiable purpose
muscle immobility
mutism
negativism
stupor.

Disorganized Schizophrenia: Disorganized schizophrenia is characterized by disorganized speech and behavior. The schizophrenic may display either flat emotions or inappropriate emotions. Although the schizophrenic displays elements of catatonic schizophrenia, he or she does not fulfill all the criteria for a catatonic schizophrenia diagnosis.

Paranoid Schizophrenia: A schizophrenic with paranoid schizophrenia experiences delusions and auditory hallucinations that result in paranoid, anxiety, and suspicion. Paranoid schizophrenia is considered the most treatable of the different types of schizophrenia.

Symptoms such as disorganized speech, catatonic behavior, flat emotions, and inappropriate behavior do not play important roles in paranoid schizophrenia. Of all schizophrenics, paranoid schizophrenics generally experience the least social disability.

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

Residual Schizophrenia: A residual schizophrenia diagnosis indicates a schizophrenic once met the symptom criteria for one of the other four types of schizophrenia. Although no longer exhibiting the severe symptoms of the other schizophrenia categories, the person is still considered schizophrenic.

A schizophrenic with a residual schizophrenia diagnosis often displays "negative" symptoms such as blunted emotions, lack of motivation, and reduced speech. Residual schizophrenics also display mild symptoms related to the symptoms of the other types of schizophrenia:

Schizophrenia Symptom	Related Residual Schizophrenia Symptoms
delusional thinking hallucinations disorganized behavior disorganized speed	odd or unusual beliefs distorted sensory perceptions odd, unusual behavior unusual speech patterns

Resources

Beers, M.H., & Berkow, R. (ed). Schizophrenia and related disorders. The Merck Manual of Diagnosis and Therapy, 17th Edition. Merck Research Laboratories, NJ, 1999.

Fauci, A., Braunwald, E., Isselbacher, K., Wilson, J., Martin, J., Kasper, D., Hauser, S. & Longo, D. (ed). Harrison's Principles of Internal Medicine, 14th Edition . McGraw-Hill, New York, 1998.

Murphy, M., Cowan, R. & Sederer, L. Blueprints in Psychiatry. Blackwell Publishing, Massachusetts, 2004.

National Library of Medicine. (updated 2004). Schizophrenia. MedlinePlus Medical Encyclopedia.

National Mental Health Information Center. (2003, April). Schizophrenia. NMHIC brochure [KEN98-0052].