Schizophrenia memory differences

People with schizophrenia use different areas of their brain to process some short-term memories, research suggests. The finding by US scientists might help explain why the condition is often linked with enduring memory problems.

The study, by Vanderbilt University in Nashville, Tennessee, found healthy subjects used the right side of the brain to remember specific locations. However, schizophrenic patients used a wider network of areas on both sides of the brain.

Researcher Professor Sohee Park said: "This suggests that while healthy people recruit a specialised and focused network of brain areas for specific memory functions, schizophrenic patients seem to rely on a more diffuse and wider network to achieve the same goal."

The researchers, who used scans to monitor brain activity during trials of memory, also found a fundamental difference in the way healthy people and schizophrenic patients made errors. When healthy people forgot, they had no confidence in their response for that trial and the brain areas used during correct memory trials remained inactive.

In other words, their pattern of brain activation was tightly coupled to their actual memory performance. However, when schizophrenic patients forgot, they were very confident that they had remembered correctly, and their brain activation pattern looked exactly the same whether they had remembered correctly or not.

Professor Park said: "Such coupling of storing incorrect information and feeling confident of one's response may be one way to think about how delusions get initiated."

Marjorie Wallace, of the mental heath charity SANE, said: "The evidence is showing that the connections in the brain are different for people with schizophrenia, leading to delusions, hallucinations and disorganised speech and behaviour. Only by understanding the fundamental changes in the brain will we be able to discover the causes and better treatments for this distressing condition, which affects one in a hundred people worldwide."

Mrs Wallace said recent research suggested that schizophrenia may be the result of the marked split in function between the two sides of the brain which, it is thought, give humans their unique capacity for language.

Paul Corry, of the schizophrenia charity Rethink, said: "Cognitive impairment, including problems with memory, is one of the most disabling symptoms of schizophrenia, but is even more poorly understood than the other main symptoms - hallucinations and delusions. "These findings offer some pointers to further research."

Mr Corry said the best way to protect people from cognitive impairment was to provide medical help and social support as early as possible in the illness.