This is a mental disorder. It's a problem with the way you perceive others. With it, you don't trust other people. You are suspicious of their motives. This makes it hard for you to work and to have friends.
We don't understand the exact cause of paranoid personality disorder. It may be linked to your genes. It's more common in people who have a family history of psychotic disorders. It's also more common in men.
If you have this disorder, you're suspicious of other people. You may think they are trying to hurt you or take advantage of you. This can lead to social isolation as you withdraw from other people and try to interact with them as little as possible. You may also be prone to violent outbursts.
Paranoid personality disorder is difficult to treat, because people who have it are often suspicious of doctors. But it can be treated with talk therapy and with medications. Your healthcare provider can create a plan that's right for you.