What are the causes of paranoid personality disorder?
We don’t really know. I would say paranoid personality disorder is part of what we consider the Cluster A group of personality disorders. Combined with schizoid and schizotypal, these personality disorders are thought to be part of this so called schizophrenia spectrum. It might actually represent milder variants of schizophrenia, and they are more common in the first degree relatives of patients with schizophrenia. This may actually be one of those personality disorders that has a genetic component to it.