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Longitudinal study of symptoms and cognitive function in chronic schizophrenia
Catherine Hughes1, Veena Kumari, William Soni
1Section of Cognitive Psychopharmacology, Division of Psychological Medicine, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.
Schizophrenia Research
|November 5, 2002
Summary
This study found that while negative symptoms in schizophrenia correlate with poorer cognitive function, symptom improvement over six months did not predict cognitive gains, except for motor speed. This suggests no direct causal link between symptom changes and cognitive recovery in chronic schizophrenia.
Area of Science:
- Neuroscience
- Psychiatry
- Cognitive Psychology
Background:
- Conflicting evidence exists regarding the relationship between symptom changes and cognitive functioning in schizophrenia.
- Understanding this relationship is crucial for developing effective treatments for chronic schizophrenia.
Purpose of the Study:
- To investigate the longitudinal relationship between changes in psychopathology and cognitive functioning in chronic schizophrenia.
- To examine this relationship using three different dimensional models of symptomatology.
Main Methods:
- Sixty-two patients with DSM-IV schizophrenia or schizoaffective disorder were assessed over 6 months.
- Symptom improvement was measured using the Positive and Negative Syndrome Scale (PANSS).
- Cognitive functioning was assessed using a comprehensive neuropsychological battery, including measures of attention, memory, psychomotor processing, and executive functioning.
Main Results:
- Severity of negative symptoms at baseline predicted poorer neuropsychological performance (IQ, verbal fluency, memory).
- Improvements in symptom ratings over time did not predict improvements in most cognitive functions.
- A significant improvement in symptom ratings predicted improvement in motor speed only.
Conclusions:
- The findings do not support a causal relationship between the course of symptoms and neuropsychological functioning in chronic schizophrenia.
- Negative symptom severity may be a more consistent predictor of cognitive deficits than symptom change over time.