system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: do people with mental diseases know they have it?
gpt
Depends on the disorder. For example, a person with OCD usually would, but a person with paranoid schizophrenia most likely wouldn't. 

People with personality disorders like borderline and narcissistic personality disorders are notorious for not realizing their behavior isn't normal as well.