Section 6.4: Eating, Substance Use, and Personality Disorders

Why Eating, Substance Use, and Personality Disorders Matter for the PANCE

This section covers a diverse array of high-yield psychiatric conditions: eating disorders, substance use disorders, and personality disorders. The PANCE focus is highly practical, testing the ability to distinguish Anorexia Nervosa from Bulimia Nervosa based on body mass index (BMI) thresholds and clinical signs, recognizing and managing life-threatening alcohol withdrawal states (Delirium Tremens) and opioid crises, and identifying the characteristic features of the ten personality disorders grouped into Clusters A, B, and C.

Eating Disorders: Anorexia Nervosa vs. Bulimia Nervosa

Distinguishing between these two disorders on the PANCE is primarily based on Body Mass Index (BMI).

Anorexia Nervosa

• Core Feature: Restriction of energy intake leading to a significantly low body weight (BMI < 18.5 kg/m²), accompanied by an intense fear of gaining weight and a distorted perception of body shape or weight.
• Subtypes:
  1. Restricting type: Weight loss is achieved through dieting, fasting, and/or excessive exercise.
  2. Binge-eating/purging type: The individual engages in episodes of binge eating followed by self-induced vomiting, or misuse of laxatives, diuretics, or enemas.
• Clinical Presentation: Lanugo (fine, downy hair), bradycardia, hypotension, hypothermia, dry skin, osteopenia, amenorrhea, peripheral edema. Purging behaviors can lead to Russell's sign (calluses or scars on the knuckles from contact with incisors during vomiting) and parotid gland hypertrophy ('chipmunk cheeks').
• Electrolytes: Hypokalemia, hypochloremic metabolic alkalosis (due to loss of stomach acid from vomiting), hypomagnesemia, and elevated BUN (dehydration).
• Management:
  • First-line: Nutritional rehabilitation (target weight gain of 1-2 lbs/week for outpatients) and psychotherapy (Family-Based Therapy is first-line for adolescents; CBT for adults).
  • Hospitalization criteria: Heart rate < 40 bpm, blood pressure < 80/50 mmHg, temperature < 97°F (36.1°C), electrolyte abnormalities, or BMI < 15 kg/m².
  • Refeeding Syndrome: A life-threatening complication of rapid refeeding in severely malnourished patients. The introduction of carbohydrates causes an insulin surge, leading to intracellular shifts of electrolytes. Characterized by hypophosphatemia (the hallmark), hypokalemia, hypomagnesemia, and fluid overload, leading to cardiac arrhythmias and delirium.
  • Pharmacotherapy: SSRIs (olanzapine can be used to promote weight gain and address obsessive thoughts about food). Bupropion is strictly contraindicated in all patients with eating disorders due to an increased risk of seizures.

Bulimia Nervosa

• Core Feature: Recurrent episodes of binge eating (eating an abnormally large amount of food with a sense of lack of control) followed by inappropriate compensatory behaviors (vomiting, laxatives, fasting, excessive exercise) to prevent weight gain.
• Weight Status: Patients with Bulimia Nervosa maintain a normal or overweight BMI (≥ 18.5 kg/m²). This is the key distinguishing factor from purging-type anorexia.
• Clinical Presentation: Parotid gland hypertrophy, dental enamel erosion (perimylolysis, especially on lingual surfaces), Russell's sign, and subconjunctival hemorrhages (from the pressure of vomiting).
• Electrolytes: Hypokalemia, hypochloremic metabolic alkalosis.
• Management:
  • Psychotherapy: CBT is the most effective first-line treatment.
  • Pharmacotherapy: Fluoxetine is the only FDA-approved medication for bulimia and is effective at a high dose (60 mg/day) to reduce binge-purge cycles. Bupropion is contraindicated due to seizure risk.

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Substance Use Disorders: Alcohol and Opioids

Alcohol Withdrawal

Alcohol acts as a central nervous system depressant by enhancing GABA (inhibitory) activity and inhibiting NMDA glutamate (excitatory) receptors. Abrupt cessation leads to a loss of GABA inhibition and a surge in NMDA excitation.

Clinical Timeline of Alcohol Withdrawal

1. Mild Withdrawal (6 to 36 hours): Tremors, anxiety, headache, palpitations, diaphoresis, gastrointestinal upset, normal mental status.
2. Withdrawal Seizures (12 to 48 hours): Generalized tonic-clonic seizures, often occurring as a single event or brief flurry.
3. Alcoholic Hallucinosis (12 to 48 hours): Visual, auditory, or tactile hallucinations. Crucially, the patient's sensorium is intact (they are oriented to time, place, and person).
4. Delirium Tremens (DT) (48 to 96 hours): A medical emergency characterized by delirium (altered sensorium/disorientation), severe autonomic instability (hyperthermia, tachycardia, marked hypertension, diaphoresis), psychomotor agitation, and vivid hallucinations. Mortality is up to 5% if untreated.

Management of Alcohol Withdrawal

• Benzodiazepines: First-line therapy to prevent seizures and delirium. Dosing is guided by the Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) protocol. Long-acting agents (e.g., chlordiazepoxide, diazepam) are preferred due to smoother self-tapering.
• Hepatic Impairment Exception: In patients with advanced liver disease (common in chronic alcoholics), use the 'LOT' benzodiazepines (Lorazepam, Oxazepam, Temazepam) because they undergo direct glucuronidation and do not accumulate active metabolites.
• Thiamine (Vitamin B1): Must be administered before or concurrently with glucose/dextrose-containing IV fluids to prevent precipitating Wernicke-Korsakoff syndrome (triad of encephalopathy, oculomotor dysfunction, and ataxia).

Opioid Overdose and Withdrawal

Opioid Overdose

• Presentation: The classic triad of altered mental status (coma), respiratory depression (respiratory rate < 8-10 breaths/min), and pinpoint pupils (miosis). Other signs include bradycardia, hypotension, and hypothermia.
• Management: Secure the airway and assist ventilation. Administer Naloxone, a rapid-acting mu-opioid receptor antagonist. Dosing should be titrated to restore adequate ventilation, not necessarily to full consciousness, to avoid precipitating acute, severe withdrawal.

Opioid Withdrawal

• Presentation: While highly distressing and painful, opioid withdrawal is not life-threatening (unlike alcohol or benzodiazepine withdrawal). Symptoms include mydriasis (dilated pupils), lacrimation, rhinorrhea, piloerection ('goosebumps'), yawning, diaphoresis, severe myalgias, abdominal cramps, nausea, vomiting, and diarrhea.
• Management:
  • Symptomatic: Clonidine (alpha-2 agonist) to treat autonomic symptoms (hypertension, sweating); loperamide for diarrhea; antiemetics; NSAIDs for muscle pain.
  • Replacement Therapy: Methadone (long-acting agonist) or Buprenorphine (partial agonist, often combined with naloxone).

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Personality Disorders

Personality disorders are characterized by enduring, maladaptive patterns of behavior and inner experience that deviate markedly from cultural expectations. They are grouped into three clusters:

Cluster A ('Weird' - Odd or Eccentric)

• Paranoid: Pervasive distrust and suspiciousness of others, interpreting motives as malevolent.
• Schizoid: Voluntary social isolation. Disinterested in close relationships (including family), prefers solitary activities, flat affect, emotionally cold.
• Schizotypal: Odd, eccentric behavior and speech, magical thinking (e.g., belief in clairvoyance or telepathy), unusual perceptual experiences, ideas of reference, and severe social anxiety.

Cluster B ('Wild' - Dramatic, Emotional, or Erratic)

• Antisocial: Disregard for and violation of the rights of others, deceitfulness, impulsivity, lack of remorse. Patient must be at least 18 years old for diagnosis, with evidence of Conduct Disorder before age 15.
• Borderline: Instability of interpersonal relationships, self-image, and affect. Characterized by marked impulsivity, frantic efforts to avoid abandonment, suicidal behavior or self-mutilation, chronic feelings of emptiness, and splitting (defense mechanism where others are viewed as all good or all bad). Treatment of choice is Dialectical Behavior Therapy (DBT).
• Histrionic: Pervasive attention-seeking behavior, shallow and rapidly shifting emotions, dramatic or theatrical presentation, and use of physical appearance/seduction to draw attention.
• Narcissistic: Grandiosity, lack of empathy, need for admiration, sense of entitlement, and exploitation of others for personal gain.

Cluster C ('Worry' - Anxious or Fearful)

• Avoidant: Extreme social inhibition, feelings of inadequacy, and hypersensitivity to criticism. Unlike schizoid patients, avoidant individuals desire social interaction but avoid it out of an intense fear of rejection or embarrassment.
• Dependent: Pervasive, excessive need to be taken care of, leading to submissive, clinging behaviors and difficulty making everyday decisions without reassurance.
• Obsessive-Compulsive Personality Disorder (OCPD): Preoccupation with orderliness, perfectionism, and mental and interpersonal control at the expense of flexibility and efficiency. Unlike OCD, OCPD traits are ego-syntonic; the patient does not perceive their rigid behaviors as problematic.

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Neurodevelopmental Disorders: Attention-Deficit/Hyperactivity Disorder (ADHD)

ADHD is a neurodevelopmental disorder on the PANCE Psychiatry/Behavioral Science blueprint, characterized by inattention, hyperactivity, and impulsivity that begins in childhood and persists into adulthood in many patients.

• Diagnostic Criteria (DSM-5): Symptoms must be present before age 12, persist for at least 6 months, and occur in two or more settings (e.g., home and school/work). At least 6 inattention or 6 hyperactive-impulsive symptoms are required for children (5 for adults ≥17 years).

• Presentation Subtypes: Predominantly inattentive, predominantly hyperactive-impulsive, or combined.

• Management:

  1. Behavioral therapy — first-line for preschool-aged children (under 6 years).
  2. Stimulant medications — first-line pharmacotherapy for school-aged children and adults. Examples: methylphenidate, amphetamine salts. Mechanism: increase dopamine and norepinephrine in the synaptic cleft.
  3. Non-stimulant alternatives: Atomoxetine (SNRI — slower onset, useful with comorbid anxiety or substance use history), Guanfacine/Clonidine (alpha-2 agonists — useful for tics or sleep disturbance).

• *### Autism Spectrum Disorder (ASD) ASD is a neurodevelopmental disorder characterized by persistent deficits in social communication and social interaction, plus restricted, repetitive patterns of behavior, interests, or activities. Symptoms must be present in early developmental period.

• Core Deficits: (1) Deficits in social-emotional reciprocity, nonverbal communication, and relationships; (2) Restricted/repetitive behaviors, insistence on sameness, restricted interests, or sensory hypersensitivity/hyposensitivity.

• Screening: AAP recommends universal autism-specific screening at 18 and 24 months (M-CHAT-R).

• Management: Early intensive behavioral intervention (Applied Behavior Analysis — ABA), speech and language therapy, occupational therapy, and educational support. Risperidone and aripiprazole are FDA-approved for irritability/aggression associated with ASD. There is no medication that treats the core social-communication deficits.

• PANCE Pearl: Severity is graded Level 1 (requiring support), Level 2 (requiring substantial support), and Level 3 (requiring very substantial support).

PANCE Traps:* * Stimulant Side Effects: Insomnia, appetite suppression, growth velocity slowdown, increased blood pressure and heart rate. Schedule II controlled substances due to abuse potential — avoid in patients with active substance use disorder or cardiac arrhythmia/conduction defects. * Atomoxetine Black Box Warning: Carries an FDA black box warning for suicidal ideation in children and adolescents — monitor mood closely when initiating. * Cardiac Screening: Sudden death risk in patients with pre-existing structural cardiac abnormalities — obtain a careful cardiac history before initiating stimulants; routine ECG is not required in asymptomatic patients without cardiac history.

Classic PANCE Traps & Clinical Pearls

• The Eating Disorder Seizure Trap: Antidepressant therapy is common in eating disorders. However, Bupropion is strictly contraindicated in patients with anorexia or bulimia due to a high risk of drug-induced seizures, which are precipitated by electrolyte shifts.
• Russell's Sign vs. Weight Status: Do not assume that Russell's sign (knuckle calluses) automatically means Bulimia Nervosa. A purging anorexic patient will also have Russell's sign. The diagnosis is determined by BMI (Anorexia BMI < 18.5; Bulimia BMI ≥ 18.5).
• Alcohol Withdrawal: Intact Sensorium: If a patient is experiencing visual hallucinations but is fully oriented to person, place, and time, the diagnosis is Alcoholic Hallucinosis, not Delirium Tremens. Delirium Tremens requires delirium (altered sensorium/disorientation).
• Wernicke's: Thiamine First: When treating an intoxicated or malnourishing patient in withdrawal, always administer Thiamine before Glucose to prevent Wernicke's encephalopathy, as glucose infusion increases thiamine demand, depleting residual brain thiamine stores.