Wetenschapsforum

Years before adults develop schizophrenia, there is a pattern of cognitive difficulties they experience as children, including problems with verbal reasoning, working memory, attention and processing speed.

Drawing on a long-term study of more than 1,000 New Zealanders born from 1972 to 1973, a team led by Duke researchers has found a consistent pattern of developmental difficulties that first appeared when adult study subjects with schizophrenia were 7 years old.

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"These kids are lagging behind to begin with and they continue to fall behind," said study co-author Richard Keefe, director of Duke's Schizophrenia Research Group. Their verbal skills are initially poor, and then they develop other problems along the way, including difficulties with memory and verbal processing, key factors in learning.

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Two patterns emerged: The children who developed adult schizophrenia had early deficits in verbal and visual learning, reasoning and conceptualization that remained with them as they grew. They also showed slower development than their peers in processing speed, attention, visual-spatial problem-solving and working memory. The data argues against one theory that schizophrenia stems from a deterioration of cognitive abilities. The minds of these children grew, they just didn't grow as well.

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It's possible that a child who struggles to make sense of the world becomes more socially isolated or more delusional, Caspi said. "How does a brain that's ill-equipped to deal with novel sensations deal with the stresses of adolescence?"

With this new evidence in hand, it may be tempting to try to somehow prevent schizophrenia by treating younger patients with anti-psychotic medications, said Keefe. But you'd be treating 20 percent of kids to prevent the 1 percent occurrence of schizophrenia, meaning 19 patients were treated unnecessarily, risking side effects.

"Of course, eventually we hope we'd be able to intervene, maybe even without drugs," Keefe said. Knowing more about the early clues to schizophrenia could lead to better studies of possible cognitive interventions, he said.

The findings suggest that adult psychosis doesn't just emerge fully-formed. It probably comes from a developmental process. "What we think of as adult psychiatric disorders have their roots much earlier in life," Caspi said...

Als je 20 zulke kinderen ziet, zal er gemiddeld genomen eentje daarvan Schizofrenie krijgen. Dit terwijl de prevalentie van Schizofrenie in de algemene populatie +/- 1% is. Het gaat dus zeker (nog) niet om een perfecte voorspeller van Schizofrenie, maar toch zeggen deze cognitieve problemen al iets...

Dat 5% geen perfecte voorspeller is, vind ik zacht uitgedrukt. Gezien de bijwerkingen van antipsychotica, en het feit dat we niet weten of die middelen preventief ingezet kunnen worden (daar zijn naast de bijwerkingen nog andere tegenindicaties voor, zoals onderzoeken die aantonen dat bij "full blown" schizofrenie medicatie tussen de episodes nutteloos is en slechts tijdens de episodes zou moeten worden gebruikt)

With this new evidence in hand, it may be tempting to try to somehow prevent schizophrenia by treating younger patients with anti-psychotic medications, said Keefe. But you'd be treating 20 percent of kids to prevent the 1 percent occurrence of schizophrenia, meaning 19 patientswere treated unnecessarily, risking side effects.

"Of course, eventually we hope we'd be able to intervene, maybe even without drugs," Keefe said. Knowing more about the early clues to schizophrenia could lead to better studies of possible cognitive

interventions, he said.

vraag ik me af wat we hiermee kunnen...

...Prof. Weiner and her team gave pregnant rats a viral mimic known to induce a schizophrenia-like behavioral disorder in the offspring. This method simulates maternal infection in pregnancy, a well known risk factor for schizophrenia. Prof. Weiner demonstrated that the rat offspring were normal at birth and during adolescence. But in early adulthood, the animals, like their human counterparts, began to show schizophrenia-like symptoms.

Looking at brain scans and behavior, Prof. Weiner found abnormally developing lateral ventricles and the hippocampus in those rats with "schizophrenia." Those that were at high risk for the condition could be given drugs to treat their brains, she determined. Following treatment with risperidone and clozapine, two commonly used drugs to treat schizophrenia, brain scans showed that the lateral ventricles and the hippocampus retained a healthy size.

"Clinicians have suspected that these drugs can be used to prevent the onset of schizophrenia, but this is the first demonstration that such a treatment can arrest the development of brain deterioration," says Prof. Weiner. She says that the drugs work best when delivered during the rats' "adolescent" period, several months before they reached full maturity.

Now, anti-psychotics are prescribed only when symptoms are present. Prof. Weiner believes that an effective non-invasive prediction method (looking at the developmental trajectory of specific changes in the brain), coupled with a low dose drug taken during adolescence, could stave off schizophrenia in those most at risk.

More research is needed to see at what point changes in the brain can be detected...