Psychiatric Unit, Virgen del Camino Hospital, Pamplona, Spain
Correspondence: Dr Manuel J. Cuesta, Psychiatric Unit, Virgen del Camino Hospital c/Irunlarrea 4, E-31008 Pamplona, Spain. Email: mcuestaz{at}cfnavarra.es
The Navarrás Government provided funding for implementation of the study (grants 946/2005 and 55/2007).
Background
Cognitive impairment in schizophrenia-spectrum disorders is highly prevalent and notably influences functional outcomes.
Aims
To characterise the cognitive effectiveness of second-generation antipsychotic drugs.
Method
One hundred consecutive and previously unmedicated patients with first-episode schizophrenia-spectrum disorders were admitted. Seventy-seven completed baseline, 1-month and 6-month psychopathological and neuropsychological assessments. Patients were randomised to risperidone or olanzapine treatment. Four final treatment allocation groups were defined since patients continued treatment in their normal setting: risperidone, olanzapine, mixed and no-antipsychotic groups.
Results
There were no differences in cognitive effectiveness between the four treatment groups. Reliable change index methods demonstrated that nearly a half of patients showed an improvement in Global Cognitive Score at the 6-month assessment. Improvement on the neuropsychological tests ranged from 17 to 54%.
A strong predictor of cognitive response was poor performance on baseline neuropsychological tests; response was moderately influenced by a low premorbid scholastic performance and IQ.
Conclusions
Cognitive improvement related to second-generation antipsychotic drugs appeared within the first 4 weeks of treatment and persisted at 6 months irrespective of treatment group. Greater cognitive dysfunction at baseline and lower premorbid cognitive background predicted cognitive improvement in our sample.
Related articles in BJP: