Risperdal is an antipsychotic drug prescribed to treat certain mental and mood disorders such as schizophrenia and bipolar disorder and irritability associated with autism. Research has shown the risks Risperdal can pose to children. The largest study on the side effects of the drug in adolescents and children showed hormonal changes in male patients that led to gynecomastia, the development of abnormally large male breasts, which often requires surgery to correct.