you may have mentioned paranoia

which does fall under mental illness

The term paranoia was used to describe a mental illness in which a delusional belief is the sole or most prominent feature. In his original attempt at classifying different forms of mental illness, Kraepelin used the term pure paranoia to describe a condition where a delusion was present, but without any apparent deterioration in intellectual abilities and without any of the other features of dementia praecox, the condition later renamed schizophrenia

Posted By: SCC 28, Nov 17, 01:00:26