OBJECTIVE: Antipsychotic (AP) drugs frequently induce weight gain. The present study aimed at exploring a potential association between antipsychotic-induced weight gain and delayed negative alliesthesia for sweet stimuli. RESEARCH METHODS AND PROCEDURES: The study aimed at recruiting patients undergoing AP treatment, half of them with stable weight and the other half with documented weight gain. Negative alliesthesia to sweet stimuli was assessed through a specific procedure. RESULTS: A multivariate regression of the data obtained from the entire sample was performed to establish the relationship between alliesthesia dependent variables and weight gain as a predictor. The overall F statistic shows that there was a significant association between delayed negative alliesthesia for sweet stimuli and weight gain. CONCLUSION: Atypical antipsychotic drug-induced weight gain seems to result from a raised body weight set-point.