Memory problems could be a clue to psychosis

Jan 18 2005

University of Melbourne researchers have identified a variety of intellectual impairments, such as difficulties young people have in remembering new information, that could be a marker for later psychosis.

Researchers from the ORYGEN Research Centre and Melbourne Neuropsychiatry Centre, (both part of the University’s Department of Psychiatry) and the Department of Psychology, say this is the first large-scale study to examine a broad range of neuropsychological abilities in people considered at ultra-high risk of developing psychosis.

The study, published this month in the American Journal of Psychiatry found that people considered to be at ultra-high risk had significant impairments in IQ and aspects of visual and verbal learning when compared to people of low-psychosis risk.

The researchers also found differences between people in the high-risk group – those that did actually go on to develop a psychotic illness during the course of the study were also the ones with particular problems in learning and remembering stories and pictures before any indication they had an illness.

Researcher Dr Warrick Brewer says, “Overall, the ultra-high risk patients who became psychotic performed significantly more poorly on a verbal memory test than those who did not develop psychosis.”

“These findings are extremely important because they tell us that significant problems in thinking are apparent before the onset of psychotic illness, so may provide warning signals of impending psychosis.”

The research is also important because it gives a clue to the areas of the brain that are not performing to their potential in the weeks or months before a psychotic illness manifests.

Dr Shona Francey who is also involved in the research says, “If we can identify changes occurring in the brain before, during and after the onset of a psychotic illness it will enable us to further understand the progression of these illnesses, and hopefully ways to prevent them.”

While most studies to date have focussed on identifying mental impairments in people at genetic risk of developing schizophrenia, the Melbourne study included people at clinical risk of developing any psychotic illness.

“Psychotic illnesses are often associated with a wide range of conditions including major depressive disorder, anxiety and panic disorders and obsessive compulsive disorder, along with many others,” Dr Brewer says.

“We felt that by focussing just on schizophrenia, it was unclear whether impairments in mental functioning before the onset of the illness were specific to schizophrenia or common to a range of psychoses.”

“Our findings suggest that these impairments are a feature of psychosis in general.”

The research, which is funded by the National Health and Medical Research Council, supports previous findings by the group including impaired spatial memory, a poorer sense of smell, and lower frontal grey matter volumes in people at high risk of developing psychosis.