Risperidone. Molecular model of the drug risperidone (C23.H27.F.N4.O2). This antipsychotic drug is sold under the brand name Risperdal. It is mainly used to treat schizophrenia, bipolar disorder, and irritability in people with autism. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (dark blue), oxygen (red) and fluorine (light blue).