Abstract. Background: The aim of the study is to optimise and provide more useful tool for assessing laterality by investigating the reliability (internal consistency) of Chapman & Chapman Scale in patients with schizophrenia. Subjects and methods: 98 patients with schizophrenia were assessed with the Chapman & Chapman Scale for foot dominance. Spearman’s rank correlation coefficient and Scale reliability statistics (item-scale statistics, summary statistics for the items, Cronbach’s alpha) were used. Results: Some items of the Chapman & Chapman Scale show higher means than other items, which suggest greater contribution of these items to the total scale mean score. The scale shows good internal consistency with a positive mean correlation between the items. Conclusions: The Chapman Chapman Scale reflects leftedness more strongly and objectively, irrespectively of cultural and national differences and could be more compact and easily applicable tool for the indirect assessment of lateralization.

Key words: schizophrenia, laterality assessment, Chapman & Chapman Scale, internal consistency

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