summary
A patient admitted to a psychiatric clinic because of a psychosis, developed a stutter. In this case report we review the literature in order to explain the differential diagnosis of stuttering acquired later in life. In the patient under study we considered the late development of stuttering to be either a side-effect of olanzapine or a symptom of disorganisation. Although the precise cause is still unclear, the patient's stutter decreased considerably after olanzapine was replaced by haloperidol.