We compared the changes in weight (kg) and body mass index (BMI) (kg/m 2 ) in 52 hospitalized adolescents between baseline and after 12 weeks of monotherapy with either (i) olanzapine (OLZ) orally disintegrating tablets (ODT) (N=16; 16.6mg/day±4.4 [SD]), or (ii) OLZ standard oral tablets (SOT) (N=10; 18.0mg/day±4.2), or (iii) risperidone (N=26; 2.8mg/day±1.2). Significantly greater increases in mean weight and BMI were observed in the patients treated with OLZ SOT (8.9±5.1 [SD] kg; 1.9±0.6kg/m 2 , respectively) than in those with ODT (3.0±2.1kg; 1.1±0.8kg/m 2 ). Similarly, OLZ ODT treatment was associated with significantly greater increases in weight and BMI than risperidone (1.0±1.8kg; 0.4±0.7kg/m 2 ). These findings suggest that adolescents gain less weight with OLZ ODT than OLZ SOT, possibly because the former formulation shortens the time of interaction with digestive serotonin receptors mediating satiety.