Psychiatry Study Resources | Addiction Psychiatry

Naltrexone Quick Revision

Parameter	Details
Drug Class	μ-opioid receptor antagonist; Opioid antagonist class
Mechanism	Blocks μ-opioid receptors → reduces reward salience and craving → decreases addictive behavior reinforcement
Indications	• Alcohol use disorder (FDA-approved) • Opioid dependence (FDA-approved) • Gambling disorder • Behavioral addictions • Self-harm in BPD
Dosing	• Oral: 50-100mg daily (most common: 50mg) • IM: 380mg monthly (extended-release) • Dosing adjustments may be needed in renal impairment
Evidence (Alcohol)	• Reduces heavy drinking (NNT ~12) • Reduces craving • Landmark studies: Volpicelli 1992, O'Malley 1992, COMBINE 2006 • Meta-analysis: Jonas 2014 (JAMA), Rösner 2010 (Cochrane)
Advantages	• Well-tolerated • Evidence-based • Works on reward circuit directly • Safe in mild-moderate liver disease • Transdiagnostic applications
Side Effects	• Nausea (most common) • Headache, dizziness • Abdominal pain • Insomnia • Generally mild and transient
Liver Safety	• Safe in mild-moderate liver disease • Contraindicated in acute hepatitis • Decompensated cirrhosis: avoid • Monitor: baseline LFTs, then 3-6 monthly
Contraindications	• Acute opioid dependence (not yet detoxified) • Acute hepatitis • Opioid use within 7-10 days • Allergy to naltrexone
Drug Interactions	• Minimal significant interactions • May require dose adjustment with certain medications • No interaction with SSRIs or most antidepressants
Clinical Pearls	• Best for high-craving phenotype • Safe in mild-moderate liver disease (monitor) • Underused in behavioral addictions • Long-acting IM form better for poor oral adherence • Combine with psychotherapy for best outcomes

Key Addiction Psychiatry Medications

Acamprosate

Class: GABA modulator

Mechanism: Restores glutamate-GABA balance disrupted by alcohol

Indication: Alcohol use disorder maintenance

Dosing: 666mg TID (666-1998mg daily)

Advantage: Safe in liver disease, no hepatotoxicity concerns

Note: Renal excretion; adjust in renal impairment

Disulfiram

Class: Aldehyde dehydrogenase inhibitor

Mechanism: Creates aversion to alcohol (disulfiram reaction)

Indication: Alcohol use disorder (behavioral deterrent)

Dosing: 250mg daily

Advantage: Strong behavioral component; excellent for motivated patients

Caution: Requires patient understanding and commitment

Buprenorphine

Class: Partial μ-opioid agonist

Mechanism: Partial agonism reduces withdrawal and craving

Indication: Opioid use disorder (maintenance, induction)

Dosing: 2-32mg daily (divided doses)

Advantage: Safer than methadone, lower overdose risk

Note: Lower potential for misuse than methadone

Methadone

Class: Full μ-opioid agonist (synthetic)

Mechanism: Full agonism; long half-life prevents withdrawal

Indication: Opioid use disorder (maintenance only)

Dosing: 60-120mg daily (induction 20-30mg)

Advantage: Long-acting; effective for severe dependence

Caution: QT prolongation risk; strict monitoring required

Mechanism-Based Psychiatry Framework

Dopamine & Reward Circuits

Circuit: VTA → Nucleus Accumbens → Prefrontal Cortex
Neurotransmitter: Dopamine drives "wanting," motivation, and reward-seeking behavior
Dysfunction in: Addiction, ADHD, depression (anhedonia)
Treatment approach: Dopamine agonists (methylphenidate, amphetamines for ADHD); dopamine antagonists/modulators (antipsychotics); reward circuit interventions (naltrexone, behavioral therapies)

Serotonin & Mood/Anxiety Circuits

Circuit: Dorsal raphe → limbic system → prefrontal cortex
Neurotransmitter: Serotonin regulates mood, anxiety, impulse control
Dysfunction in: Depression, anxiety disorders, OCD, impulse control issues
Treatment approach: SSRIs (first-line for depression/anxiety/OCD); serotonin precursors (tryptophan); combination therapies

GABA & Inhibitory Control

Role: Primary inhibitory neurotransmitter; reduces neuronal excitability
Dysfunction in: Anxiety, seizures, withdrawal syndromes
Treatment approach: Benzodiazepines (GABA-A agonists); buspirone (alternative); acamprosate (GABA modulation in addiction)

Glutamate & Excitatory Balance

Role: Primary excitatory neurotransmitter; neuroplasticity and learning
Dysfunction in: Addiction (learned behavior), depression, schizophrenia
Treatment approach: Memantine (NMDA antagonist for cognitive disorders); ketamine (NMDA antagonist emerging for depression); acamprosate (glutamate modulation)

Opioid System & Reward/Pain

Role: Mu, kappa, delta receptors; reward, pain modulation, affect
Dysfunction in: Opioid use disorder, pain syndromes, some affective disorders
Treatment approach: Naltrexone (μ-antagonist for addiction), buprenorphine (partial agonist), methadone (full agonist)

Exam-Oriented Clinical Pearls

Addiction Psychiatry Essentials

Addiction is a reward circuit disorder, not willpower failure
Craving is time-limited and neurobiologically based
Tolerance and withdrawal are neuroadaptation markers
Naltrexone: NNT 12 for heavy drinking reduction
Always assess for dual diagnosis (addiction + psychiatric)
Psychotherapy + pharmacotherapy synergistic
Relapse is common; continuation treatment essential

Diagnostic Criteria (DSM-5)

≥2 criteria in 12 months = Substance Use Disorder
Mild (2-3), Moderate (4-5), Severe (≥6 criteria)
Tolerance, withdrawal, continued use despite harm
Impaired control, social impairment, risky behavior
Craving is a diagnostic criterion
Not just increased use; also failed reduction attempts

Treatment Planning

Assess for withdrawal risk (CIWA for alcohol)
Detoxification vs. maintenance therapy decision
Medication selection based on craving phenotype
Psychotherapy: CBT, MI, family therapy indicated
Relapse prevention planning
Psychosocial support and 12-step groups beneficial
Regular monitoring: urine drug screens, LFTs

Behavioral Addictions

Gambling disorder only non-substance addiction in DSM-5
Same neurobiology as substance addictions
Gaming, internet, sexual behavior patterns emerging
Naltrexone effective in gambling (RCT evidence)
Behavioral therapy primary; medication supportive
Often comorbid with depression, ADHD, anxiety
Assess family history of addiction

Frequently Asked Questions

What is the best way to use these study materials?

These materials work best as quick reference guides during exam preparation. Use the naltrexone table for drug comparison questions, the mechanism section for pharmacology understanding, and clinical pearls for case-based exam questions.

Should I memorize the naltrexone table?

Focus on understanding mechanism, indications, evidence base, and clinical pearls rather than memorizing dosages. Understand WHY naltrexone is used in certain conditions and WHEN to use alternatives.

How do these materials relate to the full CME course?

These study notes provide quick summaries of concepts covered extensively in the CME masterclass. For deeper understanding, refer to the full course materials on the /cme page.

Are these materials updated with latest evidence?

Yes. All study materials incorporate the latest evidence through 2026. Key studies and evidence are based on current literature and clinical guidelines.

How should I prepare for exam questions on addiction psychiatry?

Focus on: (1) circuit-based understanding of addiction, (2) differential diagnosis of substance vs. behavioral addictions, (3) medication evidence and selection criteria, (4) safety monitoring, (5) psychotherapy integration, and (6) dual diagnosis management.

Can I download these study materials?

Yes. PDF study guides with all materials including naltrexone tables, mechanism summaries, and clinical pearls can be downloaded for offline study and easy reference.

Study Resources