Cognitive performance and cigarette smoking in first-episode psychosis.

The purpose of this study is to describe possible differences in cognitive functioning between smoking and non-smoking patients with first-episode psychosis and to determine whether there is a better cognitive profile associated with smoking. We assessed 61 first-episode psychosis patients with a neuropsychological battery that included computerized measurements of attention, working memory, and executive functioning. Patients were grouped into two categories: non-smokers (0 cigarettes/day; n = 30) and smokers (>/=20 cigarettes/day; n = 31). No significant differences were detected in sociodemographic and clinical data between the two groups. For attention tasks, smokers exhibited shorter reaction times in the sustained attention test than non-smokers (P = 0.039) and needed less time to complete the Stroop interference test (P = 0.013). In the working memory task, smokers exhibited shorter reaction times (P = 0.029) and presented a significantly lower percentage of omission (P = 0.002) and commission errors (P = 0.020) than non-smokers. For executive functioning, no differences were detected between groups in performance on the Wisconsin Card Sorting Test. Results indicate that first-episode psychosis patients who are nicotine users have better cognitive functioning in the areas of attention and working memory than patients who are not nicotine users. This study supports the cognitive approach to the self-medication hypothesis, to explain the high rates of cigarette smoking among psychosis patients. These results may be relevant for developing new strategies involving nicotinic receptors for cognitive enhancement in psychosis.

Course of cognitive functioning in first-episode psychosis: a comparison between schizophrenia and non schizophrenia psychosis.

AIMS: To describe the course of cognitive functioning in first-episode psychosis and to determine possible differences in the degree and trajectory of cognitive deficits between schizophrenia and non-schizophrenia first-episode psychosis. METHOD: We assessed attention, working memory, and executive functioning in 57 patients with first-episode psychosis both at baseline and at 1-year of follow-up. RESULTS: For the overall group, significant reductions were found in the percentage of omission and commission errors for the sustained attention task (p<0.001 and p=0.001, respectively), in the total time to complete the Stroop-I task (p<0.001), in the percentage of omission errors for the working memory task (p=0.001), and in the percentage of perseverative errors for the Wisconsin card sorting test (WCST; p<0.001), as well as a significant increase in the number of categories completed in the WCST (p<0.001). The remaining cognitive variables analyzed remained stable (4 of the 10 variables tested). The pattern of change was similar for patients with schizophrenia (n=20) and non-schizophrenia (n=37) in the areas of attention and working memory. For executive functioning, the non-schizophrenia group showed a more beneficial pattern of change. No significant differences were detected in cognitive performance among subgroups at baseline or at the 1-year follow-up. CONCLUSION: The course of cognitive deficits in first-episode psychosis showed significant improvements over the 1-year period in the areas of attention, working memory and executive functioning. Neuropsychological performance did not seem to be specific enough to distinguish between patients with schizophrenia and non-schizophrenia first-episode psychosis, at least during the first year.