A 34-year-old man is brought to a psychiatric hospital by friends for erratic behavior. He has been up for the past several nights painting his apartment walls purple and reading the Bible out loud, as well as talking fast and making sexually provocative comments. Collateral information from family reveals 2 similar episodes last year. Mental status exam is notable for labile affect and grandiose delusions. Urine toxicology is negative. The patient is admitted and started on lithium for mania. His symptoms resolve within 2 weeks. How should this patient’s lithium be managed in anticipation of discharge?

Continue lithium until a therapeutic serum lithium level is reached, then taper it

Cross-taper lithium to valproic acid for maintenance therapy

Discontinue lithium, but re-start in the future if the patient has another manic episode

Cross-taper lithium to aripiprazole for maintenance therapy

A 27-year-old man comes to the physician for a follow-up examination. Paroxetine therapy was initiated 6 weeks ago for a major depressive episode. He now feels much better and says he is delighted with his newfound energy. He gets around 8 hours of sleep nightly. His appetite has increased. Last year, he had two episodes of depressed mood, insomnia, and low energy during which he had interrupted his job training and stopped going to the gym. Now, he has been able to resume his job at a local bank. He also goes to the gym three times a week to work out and enjoys reading books again. His temperature is 36.5°C (97.7°F), pulse is 70/min, and blood pressure is 128/66 mm Hg. Physical and neurologic examinations show no abnormalities. On mental status examination, he describes his mood as "good." Which of the following is the most appropriate next step in management?

Continue paroxetine therapy for 2 years

Switch from paroxetine to venlafaxine therapy

Continue paroxetine therapy for 6 months

Switch from paroxetine to lithium therapy

Maintenance therapy principles for USMLE Step 2 CK: High-Yield Psychiatry Lessons

Indications & Goals - The Long Game

Primary Goal: Prevent recurrence of manic and depressive episodes, enabling long-term mood stability (euthymia).
Indications for lifelong maintenance:
- After 1 severe manic episode (e.g., requiring hospitalization, psychotic features).
- After ≥2 confirmed bipolar mood episodes.
- Patients with a strong family history of severe bipolar disorder.

⭐ The risk of recurrence without maintenance therapy is extremely high, approaching >90% within 5 years after a manic episode.

Bipolar disorder: Long-term course and treatment

First-Line Mood Stabilizers - The Classics

Core agents for long-term prevention of manic and depressive episodes. Choice depends on the patient's predominant polarity (mania vs. depression) and side effect profile.

Agent	Primary Efficacy	Key Adverse Effects (AEs)	Monitoring Pearls
Lithium	Mania prevention	Tremor, polyuria (nephrogenic DI), hypothyroidism, teratogen (Ebstein anomaly)	Therapeutic window: 0.6-1.2 mEq/L. Check TSH, BUN/Cr, Ca²⁺. 📌 LMNOP: Lithium, Movement, Nephrogenic DI, O (hypOthyroidism), Pregnancy problems.
Valproate	Mania prevention	Hepatotoxicity, pancreatitis, thrombocytopenia, alopecia, significant weight gain. Highly teratogenic (neural tube defects).	Check LFTs, CBC (platelets).
Lamotrigine	Depression prevention	⚠️ Stevens-Johnson Syndrome (SJS), benign rash.	💡 Slow dose titration is critical to minimize SJS risk. Valproate ↑ lamotrigine levels.

Adjuncts & Alternatives - The New Guard

Second-generation antipsychotics (SGAs) are crucial, especially for patients with psychosis or when traditional mood stabilizers are insufficient/poorly tolerated. Many are FDA-approved for maintenance monotherapy.

Key Agents: Aripiprazole, Olanzapine, Quetiapine, Risperidone (long-acting injection), Ziprasidone.

⭐

Olanzapine and Clozapine carry the highest risk of metabolic side effects (weight gain, dyslipidemia, hyperglycemia) - a major consideration for long-term use.

Maintenance Agent Selection Flowchart

Safety & Monitoring - The Watchful Eye

Long-term vigilance is key to prevent toxicity and manage side effects.

Monitoring Parameter	Lithium	Valproate	Second-Gen Antipsychotics
Baseline	BUN/Cr, TSH, ECG, Ca²⁺, hCG	LFTs, CBC, hCG	Lipids, Glucose/A1c, Wt/BMI
Ongoing	Drug Level, BUN/Cr, TSH	LFTs, CBC	Lipids, Glucose/A1c, Wt/BMI
Therapeutic Level	0.6-1.2 mEq/L	50-125 µg/mL	N/A

⭐ Lithium-induced nephrogenic diabetes insipidus (polyuria, polydipsia) is a classic, testable side effect from chronic use.

ECG: T wave flattening and U waves due to Lithium effect

High‑Yield Points - ⚡ Biggest Takeaways

Lithium is a first-line mood stabilizer for long-term maintenance.

Valproate is particularly effective for mixed episodes and rapid cycling.

Lamotrigine is best for preventing bipolar depression but requires slow titration due to SJS risk.

Second-generation antipsychotics (e.g., quetiapine) can be used as monotherapy or adjuncts.

AVOID antidepressant monotherapy due to the high risk of inducing mania.

Regular monitoring of drug levels (Lithium) and side effects is crucial.

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