OBJECTIVES: In the current study, we quantitatively estimated changes in appetite and eating behavior of bipolar disorder patients during the pharmacotherapy. We also investigated their contribution to the weight gain and their association with specific food-craving characteristics of the patients. METHODS: Subjects included forty-one bipolar disorder patients and fifty-six controls. Currently sustained natures of food craving were assessed using the General-Food Craving Questionnaire-Trait (G-FCQ-T) and changes in appetite and eating behavior were measured using the Drug-Related Eating Behavior Questionnaire (DR-EBQ). RESULTS: Compared to the control group, the patients' group showed significantly higher body mass index (t=2.028, p=0.045). The patients' group had significantly higher 'Preoccupation with food' factor score of G-FCQ-T (p=0.016) than that of the control group. Hierarchical multiple regression analysis showed that only 'preoccupation with food' factor independently predicted psychotropic medication-induced appetite change. CONCLUSIONS: Appetite change while receiving psychotropic medication seems to be related to the weight-gain and associated with craving natures of 'preoccupation with food' in bipolar disorder. Appetite and/or eating behavioral changes measured by G-FCQ-T and DR-EBQ could be regarded as an important mediating factor in future studies exploring biological mechanisms of weight gain related with pharmacotherapy for bipolar disorder.