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.
Current animal research on schizophrenia has relied on drugs to create the delusions, mood changes and paranoia that characterize this brain disorder.
Breeding animals that develop schizophrenia will help researchers better understand the disease, which affects about 1 percent of the world's population.
"We can use them to explore how external factors like stress or viruses may worsen symptoms," 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.
The research builds on the discovery in recent years of the DISC1 gene that 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.
"However, this mouse model will help us fill many gaps in schizophrenia research," he said in a statement.
