Glycogen synthase kinase-3 (GSK-3) is a downstream component of the Wnt pathway and recent studies have reported abnormal levels of GSK-3β in schizophrenia. In a sample of 147 schizophrenic patients and 212 healthy individuals, we analyzed two common SNPs at position –1727 A/T and –50 C/T and a (CAA)_n repeat polymorphism localized in intron 1 of the gene. The results showed that the allele, genotype and haplotype distributions for the three polymorphisms investigated do not differ between schizophrenic patients in general and control subjects. However, in the subtype of paranoid schizophrenic patients, we found that the (CAA)₃/(CAA)₅ heterozygotes were more often represented. Although taken from a small sample, our results support the reports that GSK-3β appears to be involved in a subtype of schizophrenic patients, but not in schizophrenia in general. In conclusion, we would speculate that this gene may be linked to some features of psychotic disorders rather than to schizophrenia itself.