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Childhood schizophrenia, though exceedingly rare, appears to share anatomical abnormalities with the adult version of the disease and to arise from the same underlying pathological processes.
The emerging picture of childhood schizophrenia suggests that the phenomenon--previously viewed as a variant of autism or a distinct disorder entirely--is actually an earlier, more dramatic, and more devastating manifestation of the same disease process that typically occurs in young adults, say Judith Rapoport, M.D., and colleagues at the child psychiatry branch at the National Institute of Mental Health.
Rapoport told Psychiatric News that childhood psychosis--though at least five times as rare as adult-onset schizophrenia--fits into the prevailing thinking about schizophrenia as a disorder that arises from faulty in utero development of the brain, caused by genetic mutations in combination with a variety of other possible contributing causes.
What is different about the childhood version of schizophrenia, Rapoport and colleagues believe, is not the underlying cause or pathological process, but the extent and magnitude of damage to brain development.
Children with schizophrenia have an insidious onset, as opposed to the episodic nature of adult disease.
Moreover, some of the abnormalities seen in adults with schizophrenia, especially with respect to brain and thalamus size, appear to be exacerbated in children with the disease, she explained.
In addition, children continue to deteriorate after a psychotic break: preliminary evidence indicates that they have a dramatic increase in brain ventricular volume during adolescence compared with healthy teens.
Thus, whatever goes wrong in brain development in adults who develop schizophrenia appears to be expressed more dramatically and consistently over time in children with the disorder, Rapoport said.
"Putting all the data together--from imaging, medical history, and clinical presentation--it appears as if there is a more constant interference with normal brain development. . .that might be accounted for by some modifying genes or a different pattern of expression of some of the genes that cause schizophrenia," she explained.
The similarity of childhood schizophrenia to the adult version, and the fact that it appears to be a more extreme manifestation of the same underlying processes, means that the study of childhood psychosis can yield important information about schizophrenia in general, Rapoport says.
She believes that the gene or genes contributing to adult-onset schizophrenia may be "turned on" earlier, with a more dramatic effect.
"This is a group that resembles true Kraepelian schizophrenia with a different kind of course," she stated. ". . .If you hypothesize a gene, which we do, there appears to be a bigger dose that is expressed more potently. . . ."
The anatomical similarity of childhood schizophrenia and adult-onset disease was demonstrated in a study using magnetic resonance imaging published in the July 1996 Archives of General Psychiatry.
Brain anatomic abnormalities--including total cerebral volume, thalamic area, ventricle size, and others--found in 21 children with early-onset psychosis were similar to those reported for adult populations, according to the report.
"Further research on these rare cases will have important implications for later-onset schizophrenia," the authors write. "Given substantial data supporting a neurodevelopmental basis for schizophrenia, the findings of this study raise important questions about whether there is evidence for late brain maturational shifts in those with childhood-onset schizophrenia. These questions can be addressed, however, only with a larger sample, including younger subjects who can be scanned closer to the time of onset. It is possible that scans at the time of onset would show more striking quantitative differences."
In addition to Rapoport, the authors of that study are Jean A. Frazier, M.D., Jay N. Giedd, M.D., Susan Hamburger, M.A., M.S., Kathleen E. Albus, Debra Kaysen, A. Catherine Vaituzis, Jagath C. Rajapahse, Ph.D., Marge Lenane, M.S.W., Kathleen McKenna, M.D., Leslie Jacobsen, M.D., Charles T. Gordon, M.D., and Alan Breir, M.D.
Rapoport noted that while children with schizophrenia are quite ill and tend to have a worse course than later-onset patients, some have responded dramatically to treatment with clozapine.
She also echoed her fellow researchers' call for further research and encouraged clinicians or others who know of cases of early-onset psychosis to call Marge Lenane at NIMH at (301) 496-6080.
(Psychiatric News, January 17, 1997)