U.S. researchers create schizophrenic mice

A mouse is seen in a laboratory in a file photo. Scientists have genetically engineered mice that develop the physical and psychological characteristics of schizophrenia, U.S. researchers said on Monday.

CHICAGO (Reuters) - Scientists have genetically engineered mice that develop the physical and psychological characteristics of schizophrenia, U.S. researchers said on Monday.

They said the finding will help improve understanding of the disease and help develop drugs to treat it.

"Our goal is trying to identify a strategy that may cure the pathophysiology of schizophrenia," said Dr. Akira Sawa of Johns Hopkins University School of Medicine in Baltimore, Maryland, whose work appears in the journal Proceedings of the National Academy of Sciences.

Current animal research on schizophrenia has relied on drugs to create the delusions, mood changes and paranoia that characterize this brain disorder.

Engineering animals to develop schizophrenia will help researchers better understand the disease, which affects about 1 percent of the world's population.

Sawa said the animals can be used to explore how external factors like stress or viruses may aggravate symptoms.

But animal rights groups said such experiments are cruel and unlikely to yield results.

"Of all the experiments on animals, the least justifiable are the psychological experiments because human mental disease is such a uniquely human feature," said Jessica Sandler of the People for the Ethical Treatment of Animals.

"When we have the power of gene sequencing ... and functional MRIs that show the firing patterns of individual neurons in the brain, there is absolutely no need for this kind of cruelty to animals," she said in a telephone interview.

Sawa said although the approach is new to schizophrenia, it is not new to mental diseases.

"It is actually the same approach that people have done to try to cure Alzheimer's disease," he said in a telephone interview.

The research builds on the discovery in recent years of the DISC1 gene, which sharply increases the risk of schizophrenia.

When these genetically altered mice matured, they showed increased agitation in open spaces and had more trouble finding hidden food than healthy mice and less interest in swimming.

The researchers believe these symptoms parallel the hyperactivity, impaired sense of smell and apathy found in humans with schizophrenia.

Scans of their brains also revealed changes in structure that resemble those in humans with the disease.

The schizophrenic mice had milder cases than humans. Sawa and colleagues think that may be because more than one gene is needed to trigger the disease.

But he said this mouse model will help fill many gaps in schizophrenia research.