The relationship between schizoaffective disorder, schizophrenia, and mood disorders is not well understood.
Evaluating and comparing cognitive impairment in these disorders can help clarify how these disorders are related. To further our understanding of these conditions, Rong Xiao, PhD, MD, Roxanne L. Bartel, MD, and John Brekke, PhD, MSW, conducted a study to examine cognitive impairment in people with schizoaffective disorder, schizophrenia, and mood disorders. Their findings have been published in a recent issue of the journal Social Work Research, published by NASW Press.
Their study compared the severity of neurocognitive and social cognitive impairments between patients with schizophrenia, schizoaffective disorder, and mood disorder. Details of the study can be found in the journal.
The study produced three major findings:
- First, there was no significant difference between the performance of participants with schizoaffective disorder and mood disorders in the cognitive domains that were tested.
- Secondly, participants with schizophrenia had worse performance than those with schizoaffective disorder and mood disorders in the cognitive domains of speed of processing, working memory, visual learning, reasoning and problem solving, and social cognition, after controlling for gender, age, years of education, and substance use disorder.
- Finally, social cognition was the most important variable to distinguish schizophrenia from the other two diagnoses. Low scores in social cognitive function predicted the diagnosis of schizophrenia.
These conclusions are consistent with previous studies that have shown that people with schizophrenia have worse cognitive function than those with schizoaffective disorder and mood disorders; there is generally no difference found in cognition between people with schizoaffective disorder and mood disorders.
Their study is the first one to use a classification tree to compare the importance of different aspects of cognition in differentiating severe mental illnesses. Also, this study found social cognition to be the most significant variable to distinguish schizophrenia from the other two diagnoses. Their study does not mean that social cognition should be added to the diagnostic criteria of severe mental illnesses or override the importance of symptomatic criteria, but it can provide diagnostic and predictive value, which is perhaps the most promising cognitive aspect to be included in the assessment and treatment of severe mental illnesses.
This study has several practical implications:
- First, their findings show that assessment of social cognition and advanced neurocognition may be a useful tool in the diagnosis of schizophrenia.
- Second, improving cognitive function may be a practical treatment goal for severe mental illnesses.
- Finally, the research suggests that it is worth exploring an effort to simplify the diagnostic classification system.
The study’s authors think these findings are promising, but also call for more research in this area to better provide appropriate therapies for people with severe mental illnesses.