New research published online today in the British Journal of Psychiatry, suggests an association between the loss of brain grey matter tissue and the development of negative symptoms in people with schizophrenia.
Schizophrenia remains a major cause of disability, with substantial personal and economic costs. Classically, the clinical features of schizophrenia are divided into positive symptoms and negative symptoms. It is the positive symptoms that are the ones which are used to diagnose the condition as these are the ones that appear earliest, and it is these symptoms which can be relieved with medication. These include changes in behaviour or thoughts, such as hallucinations or delusions.
The negative symptoms are however the arguably more disabling, and as yet there is no form of treatment which can be recommended as reliably relieving them. They include problems with motivation, social withdrawal, diminished emotional responsiveness, and problems with speech and movement. Advances in the development of new treatments for negative symptoms are hampered by a lack of understanding of their causes. With a greater understanding of the causes of these symptoms, it should be possible to develop therapies to help treat them.
Previous studies into the development of schizophrenia have suggested links with cognitive impairment, and building on this and using a specific population of young people at enhanced risk of developing schizophrenia because of educational difficulties, Professor David Owens, Dr Andrew McKechanie, Professor Stephen Lawrie and colleagues at the University of Edinburgh have been researching associations between negative symptoms in schizophrenia and brain tissue loss; and in particular the loss of grey matter.
Their investigations have taken place over a six year period, during which have been able to assess the development of negative schizophrenia symptoms alongside carrying out structural MRI brain scans in a substantial population of young people considered to be at risk of developing schizophrenia. It is the first study of its type to look at a group of young individuals at high risk of psychosis due to cognitive impairment, and link observed structural brain changes to negative symptoms.
The team found that those people who developed prominent negative symptoms of schizophrenia were also more likely to also have loss of grey matter, and concluded that the brain changes seen over time were likely to relate to the presence of the negative symptoms.
These new findings compliment and add to those of previous studies could help in understanding of the reasons why negative symptoms develop in schizophrenia, and subsequently therefore in the development of treatments for these debilitating symptoms.
Professor Stephen Lawrie said:
"Negative symptoms are arguably the most disabling features of schizophrenia and yet are relatively less studied. We have shown here that their emergence in young people at high risk is associated with a loss of grey matter, although we can't be sure which one is driving the other. This and other studies about how schizophrenia develops are opening up the possibility of early detection and treatment of schizophrenia."
Dr McKechanie said:
"The underlying biology of the negative symptoms of schizophrenia remains poorly understood and effective treatments have been hard to find. The results presented do not overcome these problems but may represent a step towards meaningful understanding of the underpinnings of these disabling symptoms of schizophrenia"