5.07 Cluster B Personality Disorders

Psychiatry review for USMLE Step 1 Exam

• Cluster B personality disorders are the highest yield among all personality disorders.
• The cluster B disorders include borderline personality disorder, histrionic personality disorder, narcissistic personality disorder, and antisocial personality disorder.
• Substance abuse and comorbid mood disorders, particularly major depressive disorder (MDD), are commonly associated with cluster B disorders.
• Personality disorders are distinguished from normal personality traits by their negative impact on daily life, lack of awareness of the problem, and deviation from cultural expectations.
• Borderline personality disorder is characterized by unstable emotions, impulsivity, disturbed relationships, and potential psychotic features.
• Criteria for diagnosing borderline personality disorder include frantic efforts to avoid abandonment, unstable interpersonal relationships, identity disturbance, impulsivity, recurrent suicidal behavior, affective instability, chronic feelings of emptiness, inappropriate anger, and paranoid ideation or dissociative symptoms under stress.
• Borderline personality disorder has a high risk of suicide, especially in women, and is often treated with dialectical behavior therapy (DBT).
• Histrionic personality disorder involves excessive attention-seeking, inappropriate sexually seductive behavior, shallow emotional expression, and self-dramatization.
• Diagnostic criteria for histrionic personality disorder include discomfort when not the center of attention, sexually provocative behavior, emotional instability, attention to physical appearance, impressionistic speech, self-dramatization, and susceptibility to influence.
• Histrionic personality disorder is more common in women and is associated with the defense mechanism of regression.
• Narcissistic personality disorder is characterized by grandiosity, a need for admiration, lack of empathy, and a sense of entitlement.
• Diagnostic criteria for narcissistic personality disorder include a grandiose self-importance, fantasies of unlimited success, a belief in being unique, excessive need for admiration, sense of entitlement, exploitation of others, lack of empathy, envy, and arrogant behavior.
• Narcissistic personality disorder is exemplified by individuals who exhibit characteristics similar to a former president (not mentioned by name), including being grandiose, preoccupied with success, and envious of others.
• Antisocial personality disorder, often referred to as sociopathy, involves a disregard for others' rights, lack of remorse, criminal behavior, hostility, and manipulation.
• Antisocial personality disorder is more common in males, has a high prevalence in incarcerated individuals, and is usually preceded by childhood conduct disorder.
• Diagnostic criteria for antisocial personality disorder include failure to conform to social norms, deceitfulness, impulsivity, aggressiveness, disregard for safety, irresponsibility, and lack of remorse.

5.06 Cluster A Personality Disorders

Psychiatry review for the USMLE Step 1 Exam.

• The cluster A personality disorders include paranoid, schizoid, and schizotypal.
• These disorders are characterized by individuals who are perceived as weird, awkward, and quiet.
• Personality disorders differ from normal personality quirks based on their negative impact on daily life, lack of awareness of the problem, and deviation from cultural expectations.
• Paranoid Personality Disorder:
  • Patients are chronically suspicious and distrustful of others, without persistent fixed delusions.
  • Key characteristics include unwarranted suspicions, doubts about loyalty, reluctance to confide, reading hidden meanings, holding grudges, perceiving attacks on reputation, and suspicion of infidelity.
• Schizoid Personality Disorder:
  • Individuals prefer isolation and have difficulty forming relationships.
  • Criteria for diagnosis include a lack of interest in close relationships, solitary activities, indifference to praise or criticism, emotional coldness, and flattened affectivity.
• Schizotypal Personality Disorder:
  • Considered a less severe form of schizophrenia, with odd behavior, speech, thinking, and mild perceptual experiences.
  • Notable features include social isolation, "magical" beliefs, mild paranoia, constricted affect, and social anxiety.

5.05 Hallucinogens (Types, Intoxication, and Withdrawal)

Psychiatry review for the USME STEP 1 Exam.

• Hallucinogens are a diverse class of drugs that cause hallucinations and other symptoms.
• Common hallucinogens discussed in the podcast are LSD, marijuana, PCP, and ketamine.
• LSD activates serotonin receptors, causing visual and auditory hallucinations, time and reality distortions, mood elevation, and dilation of the pupils. No notable withdrawal symptoms.
• Marijuana acts as a depressant, stimulant, and hallucinogen. THC binds to cannabinoid receptors, increasing neurotransmitters like dopamine and serotonin. Intoxication symptoms include red eyes, anxiety, euphoria, increased appetite, dry mouth, paranoid delusions, and perceived slowed time. Mild withdrawal symptoms include irritability, depression, sleep problems, and decreased appetite. Heavy cannabis use in adolescence is linked to an increased risk of schizophrenia.
• PCP antagonizes NMDA glutamate receptors and activates dopaminergic neurons. Intoxication symptoms include increased pain threshold, agitation, hallucinations, nystagmus, ataxia, and tachycardia. No notable withdrawal symptoms.
• Ketamine is structurally similar to PCP and acts as a milder version. It causes hallucinations and dissociation and is used medically for analgesia.

5.04 Depressants (Types, Intoxication, and Withdrawal)

Psychiatry review for the USMLE Step 1 exam.

• Depressants decrease neuronal activity in the brain.
• They can work by stimulating GABAergic neurons or binding to opiate receptors.
• Common GABA-promoting depressants: alcohol, benzodiazepines, barbiturates, and inhalants.
• Opioid depressants include heroin and morphine derivatives.
• Alcohol enhances GABA receptor effects, inhibits glutamate activity, and causes intoxication symptoms such as disinhibition, slurred speech, impaired motor control, lethargy, respiratory depression, and coma.
• Alcohol withdrawal symptoms include anxiety, agitation, insomnia, nausea/vomiting, tremors, autonomic dysfunction, seizures, and can be life-threatening (delirium tremens).
• Benzodiazepines bind to the benzodiazepine receptor, enhance GABA effects, and cause intoxication symptoms similar to alcohol.
• Benzodiazepine withdrawal symptoms include anxiety, agitation, insomnia, and seizures, which are treated with a gradual tapering of the drug.
• Inhalants depress brain activity and cause symptoms such as disinhibition, paranoia, lethargy, dizziness, ataxia, slurred speech, and high doses can lead to respiratory depression and brain damage.
• Opioids bind to opioid receptors, reduce pain, improve mood, and cause intoxication symptoms like drowsiness, constricted pupils, seizures, and respiratory depression.
• Opioid overdose can be reversed with naloxone, an opioid receptor antagonist.
• Opioid withdrawal symptoms include dysphoria, anxiety, weakness, sweating, dilated pupils, and diarrhea, and can be managed with medications like methadone and buprenorphine.
• Alcohol withdrawal is an emergency and requires prompt treatment with benzodiazepines.

5.03 Stimulants (Types, Intoxication, and Withdrawal)

Psychiatry review for the USMLE Step 1 Exam.

• Stimulants increase CNS activity and activate the sympathetic nervous system.
• They can block reuptake of neurotransmitters or stimulate their release.
• Intoxication symptoms include agitation, dilated pupils, sweating, euphoria, hallucinations, and increased norepinephrine, epinephrine, dopamine, and serotonin levels.
• Prescribed stimulants: amphetamine, dextroamphetamine, and methylphenidate (used for ADHD).
• Recreational stimulants: methamphetamine, cocaine, MDMA, nicotine, and caffeine.
• Cocaine blocks reuptake of norepinephrine, epinephrine, and dopamine, and can cause hallucinations, paranoia, chest pain, and potentially cardiac death.
• Methamphetamine can cause tactile hallucinations where patients feel like bugs are crawling on their skin.
• MDMA can induce feelings of connectedness, heightened emotions, and hallucinations.
• Withdrawal from stimulants, particularly cocaine and methamphetamine, is characterized by depression, headache, malaise, fatigue, hypersomnolence, anhedonia, constricted pupils, vivid dreams, and flu-like symptoms.
• Withdrawal symptoms are opposite to the effects experienced during intoxication.

5.02 Classical and Operant Conditioning

Psychiatry review for the USMLE Step 1 Exam

• Classical Conditioning:

  • Pavlovian conditioning discovered by Ivan Pavlov, a Russian physiologist known for his experiments with dogs.
  • Learning through association.
  • Example: Conditioning dogs to respond to a noise the way they would respond to meat.
  • Involves associating an unconditioned stimulus with a new conditioned stimulus to elicit the same response.

• Process of Classical Conditioning:

  1. Start with a stimulus that produces a response (e.g., smelling pizza makes you hungry).
  2. Pair the stimulus and response with an unconditioned stimulus (e.g., receiving a text indicating pizza delivery).
  3. Eventually, the conditioned stimulus (the text notification) alone elicits the conditioned response (mouth watering).

• Extinction and Spontaneous Recovery in Classical Conditioning:

  • If the conditioned stimulus (text notification) is presented without the unconditioned stimulus (pizza), the conditioned response (mouth watering) will weaken and eventually extinguish.
  • Spontaneous recovery may occur, where the conditioned behavior briefly reappears after a period of extinction.

• Terms in Classical Conditioning:

  • Unconditioned stimulus (US): Triggers a response unconditionally.
  • Unconditioned response (UR): The response elicited by the unconditioned stimulus.
  • Conditioned stimulus (CS): Initially neutral stimulus that becomes associated with the unconditioned stimulus.
  • Conditioned response (CR): The response elicited by the conditioned stimulus.

• Operant Conditioning:

  • Developed by B.F. Skinner.
  • Learning occurs through rewards and punishments for behavior.
  • Three types of responses: neutral operants, reinforcers, and punishers.

• Examples of Operant Conditioning:

  • Positive reinforcement: Giving a child candy for good behavior.
  • Negative reinforcement: Taking away a child's phone until homework is done to increase desired behavior.
  • Positive punishment: Using physical force as punishment (not recommended).
  • Negative punishment: Taking away a child's phone to decrease unwanted behavior.

• Different Schedules of Reinforcement:

  • Continuous Reinforcement: Positive reinforcement every time a specific behavior occurs.
  • Fixed Ratio Reinforcement: Reinforcement after a specified number of correct responses.
  • Fixed Interval Reinforcement: Reinforcement after a fixed time interval with at least one correct response.
  • Variable Ratio Reinforcement: Reinforcement after an unpredictable number of responses.
  • Variable Interval Reinforcement: Reinforcement after an unpredictable amount of time.

• Summary:

  • Classical conditioning involves learning through association of stimuli.
  • Operant conditioning involves learning through rewards and punishments for behavior.

5.01 Ego Defenses

Psychiatry review for the USMLE Step 1 Exam

• Defense mechanisms protect the unconscious part of our personality from anxiety caused by unacceptable thoughts or feelings.
• Ego defenses are categorized into three groups: mature, neurotic, and immature.
• Immature defense mechanisms include projection, regression, denial, acting out, and splitting.
• Projection involves attributing objectionable thoughts or emotions to others.
• Regression is behaving in an age-inappropriate way to avoid tension associated with the current phase of development.
• Denial is not accepting or believing something to protect one's ego.
• Acting out involves giving in to socially inappropriate impulses to avoid anxiety.
• Splitting is viewing people as either all good or all bad, without considering the middle ground.
• Neurotic defense mechanisms include intellectualization, isolation of affect, displacement, rationalization, reaction formation, and repression.
• Intellectualization is overanalyzing situations or focusing on irrelevant details to avoid negative feelings.
• Isolation of affect is unconsciously limiting the experience of emotions associated with a stressful event.
• Displacement involves shifting emotions from one thing to another, which is deemed more acceptable.
• Rationalization is justifying one's behavior or negative feelings through rational explanations.
• Reaction formation is unconsciously acting opposite to an unacceptable impulse.
• Repression involves preventing thoughts or feelings from entering consciousness to avoid negative emotions.
• Mature defense mechanisms include humor, altruism, suppression, and sublimation.
• Humor is used to relieve anxiety and negative thoughts.
• Altruism involves performing beneficial acts for others to experience pleasure and relieve anxiety.
• Suppression is consciously blocking undesirable ideas, thoughts, or impulses.
• Sublimation is transforming anxiety or emotions into socially valued pursuits.
• Sublimation involves channeling negative emotions into productive and socially desirable actions.

4.08 Myasthenia Gravis and Lambert Eaton Syndrome

MSK/Rheumatology review for the USMLE Step 1 Exam

• Introduction:
  • Review of neuromuscular junction and its components: presynaptic part, postsynaptic part, synaptic cleft.
  • Cascade of events leading to the release of acetylcholine into the synaptic cleft.
• Myasthenia Gravis:
  • Autoimmune neuromuscular junction disease.
  • Fluctuating muscle weakness, especially ocular and eyelid weakness, distal limb weakness.
  • Antibodies target nicotinic acetylcholine receptors (n-AChR's).
  • Association with thymic hyperplasia and enlarged thymus.
  • Treatment: Acetylcholinesterase inhibitors (AChE inhibitors), immunosuppressants.
• Lambert Eaton Syndrome:
  • Autoimmune neuromuscular junction disease associated with cancer.
  • Fluctuating muscle weakness, autonomic dysfunction, decreased reflexes.
  • Antibodies target presynaptic calcium channels on nerve terminals.
  • Autonomic manifestations due to calcium channels also present in smooth muscle.
  • Around 50% of cases associated with an underlying malignancy.
  • Treatment: Immunosuppression, addressing underlying malignancy if present.

This high yeild podcast covers schizophrenia type disorders for the USMLE Step 1 exam.

I cover the following topics:

• Defining psychotic symptoms: hallucinations, delusions, and disorganized thoughts/speech
• Example of a delusional belief about a small being inside the body
• Schizophrenia spectrum disorders: schizophrenia, schizophreniform, and brief psychotic disorder
• Differentiating the disorders based on the duration of symptoms: brief (6 months)
• Progression from brief psychotic disorder to schizophreniform to schizophrenia
• Schizoaffective disorder: combination of schizophrenia and a mood disorder (MDD)
• Highlighting the importance of episodes with only schizophrenia symptoms in schizoaffective disorder
• Delusional disorder: focusing on delusions without hallucinations, disorganized thoughts/behavior, or mood disorders
• Contrasting delusions in delusional disorder with those in schizophrenia
• Litigious tendencies observed in delusional disorder cases
• Mood disorders with psychotic features: exploring MDD as an example
• Psychotic symptoms in MDD appear only during depressive episodes
• Clarifying the distinction between psychotic symptoms in MDD and schizoaffective disorder
• Summary: Understanding the different disorders and their symptom overlap.

4.07 Polymyositis and Dermatomyositis

MSK/Rheum review for the USMLE Step 1 Exam

• Polymyositis and dermatomyositis are autoimmune inflammatory myopathies.
• They are caused by abnormal activation of T cells that attack skeletal muscle and both cause proximal muscle weakness, especially of the shoulders and pelvic girdle muscles.
• Polymyositis develops when there is abnormal activation of CD8 T cells, while dermatomyositis is primarily attacked by CD4 T cells.
• Both are diagnosed through a muscle biopsy and the presence of elevated CK levels and several different autoantibodies.
• Dermatomyositis includes dermatologic manifestations, such as gottron papules, heliotrope rash, and shawl rash.
• Both are associated with MI, interstitial lung disease, and various types of cancer (dermatomyositis more so).
• Both diseases require prompt treatment with steroids and immunosuppressive agents.