Schizotypy and the shift from dextrality: a study of handedness in a large non-clinical sample

Numerous previous studies have reported associations between schizophrenia/schizotypy and atypical handedness. While there is broad agreement that schizophrenia/schizotypy is associated with a shift away from typical (strong right) handedness, it is not entirely clear what aspect of atypical handedness is implicated: 'ambiguous' handedness (the absence of hand preference for given actions) or 'mixed handedness' (different hand preferences for different actions). The present study used several indices of handedness (derived from the Annett scale) to address these questions in 3000 + (mostly) University student subjects recruited by electronic mail. It was found that positive schizotypy (indexed by a scale of 'unusual experiences') was associated with both aspects of atypical handedness. These findings are discussed in the light of various possible explanations of the association between handedness and schizophrenia/schizotypy.