Treatment with the atypical antipsychotic clozapine (FazaClo) may cause uncontrolled movements (tardive dyskinesia). Tardive dyskinesia is a series of uncontrolled movements such as sticking out the tongue, chewing or sucking motions, or making faces. Clozapine may also cause dystonia. Dystonia is a slow movement of a part of the body. In this case, the parts of the body most likely to have the movement are the neck, throat, and tongue. This may cause problems with swallowing and/or breathing. Dystonia is most common in younger children and males.