A 27-year-old man presents to his primary care physician for exposure to toxic materials. The patient states that when he left for work this morning he was certain that he had closed the door to his pantry. Upon returning home, he saw that the door to his pantry was wide open. The patient is certain that his neighbors have been tampering with his food and potentially poisoned him. He further states that he knows they have been trying to break into his house and steal his things. He has tried multiple times to get them evicted from the building to no avail. It is for this reason that he is certain that they are trying to get their revenge upon him. His temperature is 98.6°F (37°C), blood pressure is 115/71 mmHg, pulse is 72/min, and respirations are 12/min. The physician performs a physical exam and tells the patient that he thinks there is nothing to be concerned about, but that he should call him or come into the office if he experiences any symptoms. The patient is outraged at this news and requests a competent doctor who is not colluding with his enemies. He storms out of the office angrily, stating that he deserves the best in medical care. Which of the following is the most likely disorder that this patient is suffering from?
Paranoid personality disorder
Borderline personality disorder
Narcissistic personality disorder
Schizoid personality disorder
Paranoid personality disorder
This patient is presenting with a history of mistrust and suspicion of others without frankly psychotic features suggesting a diagnosis of paranoid personality disorder.

Paranoid personality disorder is a cluster A personality disorder that is genetically associated with schizophrenia. These patients present with a pervasive mistrust of others based on little or no evidence. These patients are inclined to believe others have bad intentions that are directed toward them. They are often odd, very emotionally cold, and typically are involved in frequent litigations. Patients can be hard to manage though they often benefit from cognitive behavioral therapy. Anxiolytics may also be helpful in calming these patients.

Triebwasser et al. review the evidence regarding the diagnosis of paranoid personality disorder. They discuss how there is relatively little research on these patients because it is difficult to recruit them for studies. They recommend considering the removal of this diagnosis and replacing it with a domain of paranoia.

Incorrect Answers:
Answer A: Borderline personality disorder presents with emotional instability, unstable relationships, and recurrent self-harm behaviors. These patients will typically demonstrate the defense mechanism of splitting (seeing things as all good or all bad). Dialectical behavioral therapy can be used in order to help these patients mitigate self-injurious behaviors.

Answer B: Intermittent explosive disorder presents with sudden episodes of aggression out of proportion to the stressor. This patient’s response is a result of his paranoia rather than an excessive response to reasonable stimuli. Cognitive behavioral therapy can be used in order to help these patients control their emotional outbursts.

Answer C: Narcissistic personality disorder presents with a grand sense of self-importance and preoccupation with success and admiration. These individuals are typically selfish and lack empathy. Though this patient’s demand for the best medical care may be reflective of narcissistic personality disorder, the majority of his behaviors point more toward a diagnosis of paranoid personality disorder.

Answer E: Schizoid personality disorder presents in patients with isolated and emotionally restricted behavior. These patients are typically alone but enjoy being alone and often seem disinterested in others. These patients typically do not seek relationships and do not seek therapy as they are not bothered by their behaviors.

Bullet Summary:
Paranoid personality disorder presents with mistrustful behavior, suspicion of others, oddness, emotional coldness, and they are typically involved in many litigations.