Variations in genes regulating neuronal migration predict reduced prefrontal cognition in schizophrenia and bipolar subjects from mediterranean Spain: a preliminary study.

Both neural development and prefrontal cortex function are known to be abnormal in schizophrenia and bipolar disorder. In order to test the hypothesis that these features may be related with genes that regulate neuronal migration, we analyzed two genomic regions: the lissencephaly critical region (chromosome 17p) encompassing the LIS1 gene and which is involved in human lissencephaly; and the genes related to the platelet-activating-factor, functionally related to LIS1, in 52 schizophrenic patients, 36 bipolar I patients and 65 normal control subjects. In addition, all patients and the 25 control subjects completed a neuropsychological battery. Thirteen (14.8%) patients showed genetic variations in either two markers related with lissencephaly or in the platelet-activating-factor receptor gene. These patients performed significantly worse in the Wisconsin Card Sorting Test-Perseverative Errors in comparison with patients with no lissencephaly critical region/platelet-activating-factor receptor variations. The presence of lissencephaly critical region/platelet-activating-factor receptor variations was parametrically related to perseverative errors, and this accounted for 17% of the variance (P = 0.0001). Finally, logistic regression showed that poor Wisconsin Card Sorting Test-Perseverative Errors performance was the only predictor of belonging to the positive lissencephaly critical region/platelet-activating-factor receptor group. These preliminary findings suggest that the variations in genes involved in neuronal migration predict the severity of the prefrontal cognitive deficits in both disorders.

[Non-specific differences in neurocognitive performance in psychotic disorders?]. / Inespecificidad de los hallazgos neurocognitivos en las psicosis?

INTRODUCTION: In the last years, there has been a growing interest in the study of cognitive functioning, not only in schizophrenia but also in other psychoses and psychiatric disorders. Attention, memory and information processing deficits may have great relevance as predictors of social adjustment and quality of life. OBJECTIVE AND METHODS: [corrected] We revised literature concerning comparative studies of neuropsychological performance in schizophrenia and affective disorders, mainly bipolar disorders. RESULTS: Studies analyzed show contradictory results. Some authors report a more global dysfunction or a more limited and concrete dysfunction in schizophrenia. However, most of the studies, especially those with homogeneous samples of psychotic affective disorders do not find any difference in cognitive functioning between schizophrenic and bipolar patients. DISCUSSION: Although some factors as sample selection, clinical state, course of the disorder, make difficult the interpretation of results, it would not exist specific deficits in any of the diagnostic groups studied.