dementia /di-menˈshi-ə/ noun (psychology)

1. Any form of insanity characterized by the failure or loss of mental powers
2. The organic deterioration of intelligence, memory, and orientation, often (senile dementia) in advancing age

dementia praecox or dementia precox /prēˈkoks/ noun

An older name for schizophrenia

senile /sēˈnīl or (esp N American) senˈīl/

1. Characteristic of or accompanying old age
2. Showing the decay of mind or body brought on by old age

sēnˈilely adverb

senility /si-nilˈi-ti/ noun

1. Old age
2. The mental infirmity of old age
3. A state of deterioration or decay

senile dementia see dementia under dement