Kids with schizophrenia yield brain clues.

Schizophrenia's mind-shattering, incapacitating symptoms usually materialize as a person stands on the brink of adulthood. Nonetheless, investigations of teenagers who developed this mental disorder as children indicate that a prolonged process of derailed brain development characterizes schizophrenia in general, a team of scientists contends.

Some researchers consider schizophrenia that takes root at or before age 12 to be distinct from its more numerous incarnations in people age 18 or older.

According to the recent results, however, adolescents who received a diagnosis of schizophrenia as children display a progressive loss of brain tissue and quirks in physiological activity that resemble patterns seen in later-onset schizophrenia. Psychiatrist Judith L. Rapoport of the National institute of Mental Health (NIMH) in Bethesda, Md., and her colleagues report their findings in two articles in the October Archives of General Psychiatry.

"These and other studies add to mounting evidence that the childhood and adult forms [of schizophrenia] are the same illness," Rapoport says. "It seems most economical to assume that a single, continuous process [of brain changes] exists from fetal through adult life."

Schizophrenia includes recurring periods in which individuals hear voices or otherwise hallucinate, experience delusions (such as believing that others control one's thoughts), and display blunted or inappropriate emotions. Social withdrawal, apathy, and an inability to care for oneself also characterize this disorder.

Although symptoms flare up quickly in young adulthood or later, schizophrenia n childhood emerges gradually and often in the wake of developmental disturbances, such as lags in motor or speech skills.

In the first of the two studies, Rapoport's team looked at magnetic resonance imaging (MRI) scans of the brains of 16 teenagers who had been diagnosed with schizophrenia as children and at those of 24 teenagers who had no current or past psychiatric conditions.

Each participant underwent brain imaging at age 14 and again at age 16.

Young people with schizophrenia began the study with unusually large, fluid-filled spaces (known as ventricles) in their brains and a reduced volume of brain tissue. Two years later, their ventricles had expanded substantially, and the teenagers had suffered marked tissue losses in the thalamus and several other brain structures. Earlier studies had linked such changes to schizophrenia.

Enlarged ventricles appear in some investigations of adult-onset schizophrenia, but neither this trait nor any other has been confirmed as a biological marker of the disorder.

Rapoport and her coworkers suspect that the MRI scans of teens with schizophrenia captured neural changes that occurred during a developmental period in which the brain proves extremely sensitive to the disorder. Ventricle expansion probably does not continue at such a rapid rate, the scientists note. The teens with schizophrenia were receiving treatment with an antipsychotic drug, clozapine, that may have contributed to their brain changes.

In their second study, the NIMH researchers found that 10 of 21 teenagers whose schizophrenia began in childhood exhibit a specific combination of physiological characteristics. They exhibit weak arousal, as indicated by electric responses in the skin, when exposed to novel stimuli and show excessive arousal when at rest. The same pattern applies to about half of patients with adult-onset schizophrenia, the scientists say.

These results support the theory that schizophrenia represents a single illness that may produce symptoms at various points in life, hold Henry A. Nasrallah and Herman A. Tolbert, both psychiatrists at Ohio State University College of Medicine in Columbus, in an accompanying comment. Ongoing brain changes rather than prenatal neural disturbances alone (SN: 6/18/94, p. 398) may underlie schizophrenia, they suggest.