A 25-year-old woman is brought to the emergency department by her boyfriend after she cut her forearms with a knife. She has had multiple visits to the emergency department in the past few months for self-inflicted wounds. She claims that her boyfriend is the worst person in the world. She and her boyfriend have broken up 20 times in the past 6 months. She says she cut herself not because she wants to kill herself; she feels alone and empty and wants her boyfriend to take care of her. Her boyfriend claims that she is prone to outbursts of physical aggression as well as mood swings. He says that these mood swings last a few hours and vary from states of exuberance and self-confidence to states of self-doubt and melancholy. On examination, the patient appears well-dressed and calm. She has normal speech, thought processes, and thought content. Which of the following is the most likely diagnosis?

Histrionic personality disorder

A 23-year-old woman is brought to the emergency department by her boyfriend 10 minutes after ingesting at least 15 acetaminophen tablets. She has been admitted to the hospital several times in the past few months after attempted self-harm. She claims that her boyfriend is “extremely selfish” and “does not care for her.” She says she feels lonely and wants her boyfriend to pay attention to her. Her boyfriend says that they have broken up 10 times in the past year because she is prone to outbursts of physical aggression as well as mood swings. He says that these mood swings last a few hours and can vary from states of “exuberance and affection” to states of “depression.” On examination, the patient appears well-dressed and calm. She has normal speech, thought processes, and thought content. Which of the following is the most likely diagnosis?

Narcissistic personality disorder

A 23-year-old female college senior comes to the physician with a 1-year history of recurrent palpitations accompanied by sweating, facial blushing, and sometimes nausea. The symptoms are worse during class when she is occasionally called out to speak, which causes her to feel embarrassed. She has been skipping class on discussion days because she is concerned that her classmates may notice her symptoms. The patient does not enjoy jogging in the park anymore and has gained 2 kg (4 lbs 7 oz) over the past 2 months. Her appetite is unchanged. She has no history of serious illness. She does not smoke or drink alcohol. She has experimented with marijuana but does not use it currently. She appears nervous and does not make eye contact with the physician. Her vitals show a pulse of 85/min, her blood pressure is 125/70 mmHg, and her temperature is 36.8°C. Mental status examination reveals full range of affect. Neurological exam shows no abnormalities. Which of the following is the most likely diagnosis for this patient's symptoms?

Schizotypal personality disorder

A 35-year-old woman presents to clinic in emotional distress. She states she has been unhappy for the past couple of months and is having problems with her sleep and appetite. Additionally, she reports significant anxiety regarding thoughts of dirtiness around the house. She states that she cleans all of the doorknobs 5-10 times per day and that, despite her actions, the stress related to cleaning is becoming worse. What is this patient's diagnosis?

Obsessive compulsive disorder (OCD)

Generalized anxiety disorder (GAD)

Obsessive compulsive personality disorder (OCPD)

A 32-year-old man comes to the physician because of a 2 month history of difficulty sleeping and worsening fatigue. During this time, he has also had difficulty concentrating and remembering tasks at work as well as diminished interest in his hobbies. He has no suicidal or homicidal ideation. He does not have auditory or visual hallucinations. Vital signs are normal. Physical examination shows no abnormalities. Mental status examination shows a depressed mood and flat affect with slowed thinking and speech. The physician prescribes sertraline. Three weeks later, the patient comes to the physician again with only minor improvements in his symptoms. Which of the following is the most appropriate next step in management?

Continue sertraline for 3 more weeks

Augment with aripiprazole and continue sertraline

Provide electroconvulsive therapy

Change medication to duloxetine

Augment with phenelzine and continue sertraline

Comorbidity with Axis I disorders for USMLE Step 2 CK: High-Yield Psychiatry Lessons

Comorbidity Overview - The Double Trouble Diagnosis

Personality Disorders (PDs) frequently co-occur with Axis I disorders (e.g., MDD, Anxiety), complicating diagnosis and worsening prognosis. This dual diagnosis often leads to greater functional impairment and treatment resistance.
Common Pairings:
- Borderline PD: Mood & Substance Use Disorders.
- Avoidant PD: Anxiety Disorders.
- Antisocial PD: Substance Use & Impulse Control Disorders.

Venn Diagram of Axis I Disorder Comorbidity

⭐ The presence of a PD significantly reduces the efficacy of standard treatments for the co-occurring Axis I disorder, requiring an integrated treatment approach.

Cluster A Comorbidities - The Weird & The Worrisome

Paranoid PD: ↑ risk for Delusional Disorder (Persecutory Type) & Agoraphobia. Chronic stress can trigger brief psychotic episodes.
Schizoid PD: Significant overlap with Major Depressive Disorder & Social Anxiety Disorder. Often lacks desire for relationships, distinguishing it from Avoidant PD.
Schizotypal PD: Strongest link to Schizophrenia; considered a "schizophrenia-spectrum" disorder.
- High risk for developing Brief Psychotic Episodes, Schizophreniform Disorder, or Schizophrenia.

⭐ Up to 50% of patients with Schizotypal PD have had at least one episode of Major Depressive Disorder.

Cluster B Comorbidities - The Wild & The Woeful

Antisocial (ASPD): High rates of Substance Use Disorders (SUDs), especially alcohol. Also strongly linked to Impulse Control Disorders (e.g., gambling).
Borderline (BPD): The most comorbid personality disorder. Overlaps significantly with Mood Disorders (MDD, Bipolar), Anxiety Disorders, PTSD, SUDs, and Eating Disorders (especially Bulimia Nervosa).
Histrionic (HPD): Frequently co-occurs with Somatic Symptom Disorder, Conversion Disorder, and Mood Disorders.
Narcissistic (NPD): Associated with SUDs (cocaine), depressive episodes following "narcissistic injury," and anxiety. Anorexia Nervosa can also be a comorbidity.

⭐ Exam Favorite: Over 85% of patients with Borderline Personality Disorder have at least one other co-existing psychiatric diagnosis, most commonly a mood disorder.

Cluster C Comorbidities - The Anxious & The Apprehensive

Avoidant PD: Marked overlap with Social Anxiety Disorder (often seen as a severe variant). High rates of comorbid Major Depressive Disorder (MDD) and other anxiety disorders like Panic Disorder due to persistent feelings of inadequacy.
Dependent PD: Frequently diagnosed with MDD, Generalized Anxiety Disorder (GAD), and Panic Disorder. Highly susceptible to developing an Adjustment Disorder, especially when a core supportive relationship is lost.
Obsessive-Compulsive PD (OCPD): Linked with Anxiety Disorders (esp. GAD) and Mood Disorders. Distinct from OCD, but they can co-exist. Shares traits of perfectionism and control with Anorexia Nervosa.

⭐ Patients with Avoidant PD deeply desire social connection but are paralyzed by fear of rejection, a key feature distinguishing them from the socially indifferent Schizoid PD.

Clinical Implications - Managing the Maelstrom

Personality disorders (PDs) worsen Axis I prognosis: ↑ symptom severity, ↑ relapse rates, and ↓ treatment adherence.
Management requires treating both disorders concurrently, not sequentially.
Prioritize stabilizing acute Axis I crises (e.g., suicidality, psychosis) first.
Psychotherapy (e.g., DBT, CBT) is the cornerstone for the PD, while pharmacotherapy targets Axis I symptoms.

⭐ Borderline Personality Disorder has the highest comorbidity with other psychiatric disorders, especially mood, anxiety, and substance use disorders, which significantly increases suicide risk.

High‑Yield Points - ⚡ Biggest Takeaways

Cluster A disorders are linked to psychotic disorders; schizotypal PD has strong genetic ties to schizophrenia.

Cluster B disorders are highly comorbid with mood disorders, substance use, and anxiety.

Borderline PD frequently co-occurs with MDD, PTSD, and substance use disorders.

Antisocial PD is strongly associated with substance use and impulse-control disorders.

Cluster C disorders are most commonly seen with anxiety disorders (e.g., Avoidant PD and social anxiety).

A co-occurring personality disorder often worsens the prognosis of the Axis I disorder.

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Comorbidity with Axis I disorders