Cluster A personality disorders

00:00 / 00:00



Cluster A personality disorders

Psychological disorders

Psychological disorders

Psychological disorders


Cluster A personality disorders


0 / 17 complete

USMLE® Step 1 questions

0 / 5 complete

High Yield Notes

4 pages


Cluster A personality disorders

of complete


USMLE® Step 1 style questions USMLE

of complete

A 30-year-old man is brought to the emergency department by the local paramedics after a motor vehicle accident. The patient is conscious and has minor lacerations over the right forearm. On further questioning, the patient says, “I was passing by a big sale on car tires, and then later on, I was involved in an accident caused by tire failure. That store was selling new tires, and therefore, other tires had to fail.” The patient believes he has a “sixth sense” which enables him to predict bad events before they happen. He lives alone at home and says, “I prefer it this way.” Past medical history is unremarkable. Vitals are within normal limits. Physical examination reveals a middle-aged man with multiple lacerations on the right forearm. On mental status examination, it is noted that the patient is wearing undergarments on the outside and multiple layers of mismatched clothing underneath. The patient has a flat affect and avoids eye contact. Which of the following is the most likely diagnosis?  

External References

First Aid








Cluster A personality disorders p. 588

Cluster B personality disorders p. 588

Cluster C personality disorders p. 588

Personality disorder p. 586, 588-588


Content Reviewers

If you were asked to describe a friend’s personality, you might describe them as generally being a creative type, or easy-going but nervous in groups.

Basically, you’re trying to summarize the personal traits that make them who they are—either how they think or how they act.

Sometimes these thought patterns or behaviors which make up a person’s personality can actually be harmful in the sense that they interfere with their day-to-day functioning in their personal life, at work, or in social settings.

If this were the case, we would say that the individual has a personality disorder.

The DSM5, or the diagnostic and statistical manual for mental disorders lists ten personality disorders that are split into three different ‘clusters’- referred to as clusters A, B, and C.

These used to be under the category “Axis 2” but that way of organizing isn’t used anymore.

Alright so cluster A personality disorders are characterized by “odd and eccentric thinking or behavior” such as believing in aliens or the Tooth Fairy at an adult age.

They include paranoid personality disorder, schizoid personality disorder, and schizotypal personality disorder, each with its own specific thought patterns and behaviors.

Paranoid personality disorder describes someone who is accusatory or generally distrustful and suspiciousness of other people without really having a reason to do so, and assumes that others will disappoint them, manipulate them, or talk about them behind their back.

Because of this, they think excessively about making sure that they have the loyalty of their friends and family.

These beliefs are so strong that they wind up affecting the way individuals act.

These people react severely if they feel that they have been lied to, or slighted in any way, which can result in their holding grudges for long periods of time.

In many ways, this behavior can totally affect the individual’s work, family life and the way they relate to those around them, creating a cycle that leads to even more paranoid behaviors, and ultimately, to social withdrawal or awkward behaviors.

Unsurprisingly, these people tend to have superficial relationships, because it’s hard to have ‘real’ bonds when you do things such as accusing your partner of cheating without having proof.

Schizoid personality disorder describes people that are aloof and avoid social interaction because they simply aren’t interested in getting to know others and not because it causes them anxiety or because they think they are possible threats.


Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.