Often, people with paranoid personality disorder don’t believe that their behavior is abnormal. It may seem completely rational to a person with PPD to be suspicious of others. However, those around them may believe this distrust is unwarranted and offensive. The person with PPD may behave in a hostile or stubborn manner. They may be sarcastic, which often elicits a hostile response from others, which may seem to confirm their original suspicions.
Someone with PPD may have other conditions that can feed into their PPD. For example, depression and anxiety can affect a person’s mood. Mood changes can make someone with PPD more likely to feel paranoid and isolated.