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 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 19-year-old man presents to the emergency room after a suicidal gesture following a fight with his new girlfriend. He tearfully tells you that she is “definitely the one," unlike his numerous previous girlfriends, who were "all mean and selfish” and with whom he frequently fought. During this fight, his current girlfriend suggested that they spend time apart, so he opened a window and threatened to jump unless she promised to never leave him. You gather that his other relationships have ended in similar ways. He endorses impulsive behaviors and describes his moods as “intense” and rapidly changing in response to people around him. He often feels “depressed” for one day and then elated the next. You notice several superficial cuts and scars on the patient’s arms and wrists, and he admits to cutting his wrists in order to “feel something other than my emptiness.” Which of the following is the most likely diagnosis for this patient?

Histrionic personality disorder

A 29-year-old man comes to the physician with his wife because she has noticed a change in his behavior over the past 2 weeks. His wife reports that he is very distracted and irritable. His colleagues have voiced concerns that he has not been turning up for work regularly and behaves erratically when he does. Previously, her husband had been a reliable and reasonable person. The patient says that he feels “fantastic”; he only needs 4 hours of sleep each night and wakes up cheerful and full of energy each morning. He thinks that his wife is overreacting. The patient has been healthy except for a major depressive episode 5 years ago that was treated with paroxetine. He currently takes no medications. His pulse is 98/min, respirations are 12/min, and blood pressure is 128/62 mm Hg. Mental status examination shows frenzied speech and a flight of ideas. Which of the following is the strongest predisposing factor for this patient's condition?

Maternal obstetric complications

A 38-year-old woman comes to the physician for a follow-up visit. She has a 2-year history of depressed mood and fatigue accompanied by early morning awakening. One week ago, she started feeling a decrease in her need for sleep and now feels rested after about 5 hours of sleep per night. She had two similar episodes that occurred 6 months ago and a year ago, respectively. She reports increased energy and libido. She has a 4-kg (8.8-lb) weight loss over the past month. She does not feel the need to eat and says she derives her energy ""from the universe"". She enjoys her work as a librarian. She started taking fluoxetine 3 months ago. On mental exam, she is alert and oriented to time and place; she is irritable. She does not have auditory or visual hallucinations. Physical examination shows no abnormalities. Which of the following is the most likely diagnosis?

Medication-induced bipolar disorder

A 33-year-old man with documented antisocial personality disorder and substance use disorder is convicted of assault. The defense attorney requests psychiatric testimony that the defendant's personality disorder diminished his capacity to conform his conduct to the law. His history includes multiple prior convictions, repeated lying, failure to sustain employment, lack of remorse, and disregard for others' safety. However, he understood the wrongfulness of his actions and planned the assault in advance. Evaluate the relationship between antisocial personality disorder and criminal responsibility.

Antisocial personality disorder does not meet criteria for insanity defense as patients retain capacity to understand wrongfulness

Chronic pattern of behavior demonstrates inability to conform conduct to law

Combination of personality disorder and substance use negates criminal responsibility

Comorbid substance use disorder supports insanity defense

Personality disorders qualify for diminished capacity due to impaired impulse control

A 26-year-old woman presents requesting cosmetic surgery consultation. She is preoccupied with achieving the 'perfect' appearance, has undergone multiple procedures, and expresses disappointment with each result. She describes herself as special and destined for greatness, becomes enraged when her primary care physician suggested psychiatric evaluation, and states she will report him for 'not understanding her needs.' She expects special treatment in the clinic and becomes irritated when kept waiting. On mental status exam, she shows intact reality testing. Analyze the most likely underlying personality structure.

Narcissistic personality disorder with difficulty tolerating narcissistic injury

Histrionic personality disorder with attention-seeking behavior

Obsessive-compulsive personality disorder with perfectionism

Borderline personality disorder with identity disturbance

Body dysmorphic disorder with poor insight

Borderline personality disorder for USMLE Step 2 CK: High-Yield Psychiatry Lessons

BPD Overview - Edge of Stability

A pervasive pattern of instability in interpersonal relationships, self-image, and affect, coupled with marked impulsivity beginning by early adulthood.
Core features include frantic efforts to avoid real or imagined abandonment, a pattern of unstable and intense relationships, and chronic feelings of emptiness.
Impulsivity in at least 2 self-damaging areas (spending, sex, substance abuse) is characteristic.

⭐ The hallmark defense mechanism is splitting-alternating between extremes of idealization and devaluation.

📌 Mnemonic: AM SUICIDE

Clinical Features - 'AM SUICIDE' Criteria

📌 AM SUICIDE

Abandonment: Frantic efforts to avoid real or imagined abandonment.
Mood Instability: Intense episodic dysphoria, irritability, or anxiety.
Suicidal Behavior: Recurrent suicidal gestures, threats, or self-mutilation.
Unstable Relationships: Pattern of intense relationships, alternating between idealization and devaluation (splitting).
Impulsivity: In ≥2 potentially self-damaging areas (spending, sex, substance abuse).
Control of Anger: Inappropriate, intense anger or difficulty controlling it.
Identity Disturbance: Markedly unstable self-image or sense of self.
Dissociative/Paranoid Symptoms: Transient, stress-related paranoid ideation or dissociation.
Emptiness: Chronic feelings of emptiness.

⭐ Splitting is a key defense mechanism, viewing people and situations in "all-or-nothing," black-or-white terms, which fuels the cycle of idealization and devaluation in relationships.

Pathophysiology - Brain, Genes & Trauma

Neurobiology:
- Brain Circuits: ↑ Amygdala activation (emotional intensity) & ↓ Prefrontal Cortex (PFC) modulation (impulsivity).
- Neurotransmitters: Dysregulation of the serotonin (5-HT) system is strongly implicated.
Genetic Predisposition: High heritability; genetic factors account for a significant portion of the risk.
Environmental Factors: Invalidating childhood environment, including abuse (physical, sexual) and neglect, is a major risk factor.

⭐ A history of childhood trauma, particularly sexual abuse, is found in ~70% of individuals with BPD.

Differential Diagnosis - BPD vs. The World

Bipolar II Disorder: BPD mood shifts are rapid, reactive (hours), lacking sustained hypomanic episodes (days-weeks).
Histrionic PD: BPD involves more self-destruction, chronic emptiness, and identity disturbance vs. HPD's theatricality.
Dependent PD: Abandonment fear in BPD → rage, impulsivity. In DPD → submissiveness, clinging.
Schizotypal PD: BPD's paranoia is transient & stress-related; STPD's is pervasive & eccentric.

⭐ BPD's affective instability is rapid (hours) and reactive to interpersonal events, unlike the sustained mood episodes (days-weeks) of Bipolar Disorder.

Management - DBT to the Rescue

Psychotherapy is the cornerstone; Dialectical Behavior Therapy (DBT) is first-line.
DBT integrates cognitive-behavioral techniques with mindfulness, focusing on:
- Mindfulness
- Distress Tolerance
- Emotion Regulation
- Interpersonal Effectiveness
Pharmacotherapy treats co-morbid conditions (e.g., depression, anxiety) but not core BPD symptoms.
- SSRIs, mood stabilizers, or antipsychotics may be used adjunctively.

⭐ High-Yield: No medications are FDA-approved specifically for the treatment of borderline personality disorder itself; pharmacotherapy targets co-occurring symptoms or disorders.

Instability in mood, relationships, and self-image is the core feature.

Intense fear of abandonment drives many of the behaviors.

Splitting is a key defense mechanism: viewing people and situations as either all-good or all-bad.

Associated with impulsivity (e.g., spending, sex, substance use) and recurrent suicidal gestures or self-mutilation.

Patients often report chronic feelings of emptiness.

Dialectical Behavioral Therapy (DBT) is the most effective, first-line treatment.

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