Schizophrenia is the most common of the psychoses. About 1% 
to 2% of people in Western countries are treated for schizophrenia 
at some time in their lives, and many additional schizophrenics 
never receive clinical attention. About half of the inpatients in 
U.S. mental hospitals are schizophrenic. The syndrome was first 
described as a single disorder by German psychiatrist Emil 
KRAEPELIN in 1896. He called it "dementia praecox," "dementia" 
referring to intellectual deterioration and "praecox" to the fact 
that the symptoms first occur in early adulthood. Swiss 
psychiatrist Eugene BLEULLER renamed the disorder "schizophrenia" 
to express his view that a prominent feature of the disorder is a 
splitting of psychic functions. Ideas and feelings are isolated 
from one another; a patient may speak incoherently, for example, 
or express frightening or sad ideas in a happy manner. Contrary 
to some popular accounts, however, schizophrenics do not have a 
"split personality" in the sense of different personalities on 
different occasions; the rare syndrome of multiple personality is 
actually a variety of NEUROSIS. 


The symptoms of schizophrenia include delusions, 
hallucinations, thought disorders, loss of boundaries between self 
and nonself, blunted or inappropriate emotional expression, 
socially inappropriate behavior, loss of social interests, and 
deterioration in areas of functioning such as social relations, 
work, and self-care. The symptoms fluctuate in occurrence and in 

Delusions are false beliefs, usually absurd and bizarre. Thus 
a patient may believe that he or she is an important historical 
personality, or is being persecuted by others, or has died, or 
that a machine controls his or her thoughts. 

Hallucinations are false sensory experiences. Most 
schizophrenic hallucinations are auditory, but some are visual or 
olfactory. The content is often grandiose, hypochondriacal, or 
religious. Some hallucinatory voices speak of matters related to 
the patient's emotional problems or delusional concerns; others 
transmit apparently irrelevant messages. 

Schizophrenic thought disorder may include a general lowering 
of intellectual efficiency, a free-associative rambling from one 
topic to another, a loss of the distinction between figurative and 
literal usages of words, reduced ability to think abstractly, 
invention of new words (called neologisms), and idiosyncratic 
misuse of common words. 


Schizophrenia occurs in all industrialized countries, and 
apparently in all other societies as well. All social classes are 
affected, but in large cities schizophrenia is three or four times 
more frequent in the lower socioeconomic classes than in the 
middle and upper classes. This difference is due in part to the 
downward social mobility of persons developing the disorder. 

Schizophrenia occurs equally often in men and women, although at 
an earlier age in men. The onset of schizophrenia is usually in 
late adolescence or early adulthood, but may also occur in later 

Possible Explanations 

A number of competing theories have been proposed to explain 
the causes of schizophrenia. Psychoanalysis, including Sigmund 
FREUD and Karl Abraham, have suggested that schizophrenia has its 
origin in a lack of affection in the mother-infant relationship in 
the first few weeks of life, or in childhood interpersonal 
relationships. Research data have not supported these claims, and 
biological interpretations now dominate. For example, 
schizophrenic episodes have been correlated with increased levels 
of the NEUROTRANSMITTER dopamine, especially in the brain's left 
hemisphere, and with lowered glucose metabolism in the brain's 
frontal lobes and basal ganglia. (Lowered metabolism at these 
sites is also observed in severe depression, but whereas 
schizophrenics have also shown lowered metabolism in the brain's 
limbic system, persons with severe depression show increased 
metabolism in this region. Notably enlarged brain ventricles are 
found in some schizophrenic patients, especially among those who 
tend to chronicity. Some investigators suspect that a slow-acting 
virus is responsible, while some others suspect traumatic brain 
damage as from birth injuries. 

A genetic factor also appears to be involved, in that 
schizophrenia tends to run in families. The incidence of 
schizophrenia is about 12% in the offspring when one parent is 
schizophrenic, about 50% when both parents are schizophrenic, 
about 10% in brothers or sisters of a schizophrenic, and about 50% 
in identical twins of schizophrenics. Adoption studies show that 
these concordance rates are largely accounted for by genes rather 
than by environment. Nevertheless, genes cannot be the sole cause 
of the disorder, since the concordance rate for identical twins is 
not 100%. Most researchers hold to a diathesis-stress theory: 
that both a biological predisposition and environmental factors 
interact to determine who becomes schizophrenic. 


Schizophrenia appears to be heterogeneous. Its subtypes 
include paranoid schizophrenia, in which delusions are prominent; 
catatonic schizophrenia, characterized by silent immobility for 
weeks or months (usually followed by a frenzy of agitation); and 
hebephrenic (disorganized) schizophrenia, characterized by 
intellectual disorganization, chaotic language, silliness, and 
absurd ideas that often concern deterioration of the patient's 
body. In practice, most patients have some symptoms consistent 
with each of these categories. Many researchers believe that 
schizophrenia consists of different disorders that have not yet 
been distinguished and that do not correspond to the traditional 


For many years PSYCHOTHERAPY was the preferred mode of 
treatment of schizophrenia, and it continues to be used. 
Electroconvulsive treatment, or SHOCK THERAPY, was introduced in 
1937 and became the prevalent mode of treatment until the late 
1950s; it is still used in some cases. Psychosurgery (lobotomy 
and lobectomy), however, which became common in the 1940s and 
1950s, is now in disrepute. Since the late 1950s schizophrenia 
has been treated primarily with antipsychotic medications, 
phenothiazines, butyrophenones, and thioxanthenes, which block the 
action of dopamine in the brain. They do not cure schizophrenia, 
but they reduce the symptoms. Up to 20% of patients using the drug 
at high dosages for long periods, however, develop motoric 
disorders known as tardive dyskinesia (TD). The diazapine drug 
clozapine avoids TD but severely lowers the number of white blood 
cells more often than do the other drugs. It can also cause 
convulsive seizures. 

Family therapy, in which family members learn to interact with 
the patient in a nonjudgmental, accepting manner, has been found 
helpful. The recent trend has been toward outpatient treatment, 
because of the belief that prolonged hospitalization is 
deleterious. This trend is controversial, however, and its 
popularity may be based on civil libertarian concerns as much as 
on evidence concerning its usefulness. Up to one-third of 
diagnosed schizophrenia sufferers substantially recover, 
especially patients who had a good social and sexual adjustment 
prior to the illness. Significant numbers improve even after 
years of severe illness, but some residual signs of the 
disorder almost invariably remain. 

Bibliography: Atkinson, J.M., Schizophrenia (1985); Henn, Fritz 
A., and Nasrallah, H. A., eds. Schizophrenia as a Brain Disease 
(1982); Howells, J.G., The Concept of Schizophrenia: Historical 
Perspectives (1990); Lidz, Theodore, and Fleck, Stephen, 
Schizophrenia and the Family, rev. ed. (1985); Shapiro, Sue A., 
Contemporary Theories of Schizophrenia (1981); Sheehan, Susan, Is 
There No Place on Earth for Me? (1982); Tsuang, M. I., 
Schizophrenia (1982); Young, Patrick, Schizophrenia (1988).