1. 疑惧；多疑
If you say that someone suffers from paranoia, you think that they are too suspicious and afraid of other people.

2. 偏执狂；妄想症
In psychology, if someone suffers from paranoia, they wrongly believe that other people are trying to harm them, or believe themselves to be much more important than they really are.

1. a psychological disorder characterized by delusions of persecution or grandeur