Suicide as a result of stereotypic behaviour in a case with semantic dementia

Semantic dementia (SD) is characterized by semantic aphasia and prosopagnosia, but it may also include behavioural disturbances such as stereotypic behaviour. We report the case of a 50-year-old man with SD accompanied by stereotypic behaviour who committed suicide despite not being in a depressive state. He initially had major depressive disorder accompanied by suicide attempts, but he gradually showed remarkable impairment in single-word semantic comprehension, naming memory, and facial recognition memory. After the diagnosis of SD, his suicidal behaviour by hanging with a cord became stereotypic and lacked seriousness. He repeatedly attempted to hang himself and finally completed suicide. The present report suggests that the risk for suicide in SD is increased not only by the presence of a depressive state, but also by stereotypic behaviour related to suicide attempts before the onset of the disorder.