Psychiatry · Year 2 · from Psychiatry
Case 2: Bipolar I Disorder - Bipolar Depression
Patient Presentation
Demographics: 29-year-old female
Chief Complaint: "I've been in bed for three weeks. I can barely move."
History of Present Illness: A 29-year-old woman with known bipolar I disorder (diagnosed at age 22 after a manic episode requiring hospitalization) presents to her outpatient psychiatrist with worsening depression. She has been in a depressive episode for 6 weeks with hypersomnia (sleeping 14-16 hours daily), hyperphagia with 12-pound weight gain, profound fatigue described as "leaden paralysis" where her limbs feel "too heavy to lift," and rejection sensitivity that has caused her to isolate from friends. She stopped going to her job as a graphic designer 3 weeks ago. She denies suicidal ideation. Her current medications include lithium 900 mg daily, which has successfully prevented manic episodes for the past 4 years. Her most recent lithium level was 0.8 mEq/L. She asks about adding an antidepressant because "they helped my friend."
Mental Status Examination:
- Appearance: Overweight female, casually dressed, fatigued appearance
- Behavior: Psychomotor slowing, speaks with effort
- Speech: Slow rate, low volume
- Mood: "Exhausted... empty"
- Affect: Constricted, mood-congruent
- Thought content: Hopelessness about recovery, no SI/HI
- Insight: Good - understands this is bipolar depression
Workup:
- Lithium level: 0.78 mEq/L (therapeutic)
- TSH: 6.8 mIU/L (mildly elevated - lithium-induced)
- Creatinine: 0.9 mg/dL (normal)
- PHQ-9: Score 21 (severe depression)
Diagnosis: Bipolar I Disorder, current episode depressed, severe
Treatment:
- Discussed the risks of antidepressant-induced mania/mood switching in bipolar disorder
- Added quetiapine XR 50 mg at bedtime, titrated to 300 mg over 2 weeks (FDA-approved for bipolar depression)
- Continued lithium at current dose
- Started levothyroxine 25 mcg for subclinical hypothyroidism
- Discussed importance of sleep regulation and social rhythm stability
- Referral for interpersonal and social rhythm therapy (IPSRT)
- Antidepressants avoided as monotherapy; if needed, bupropion would be safer option combined with mood stabilizer
- At 4-week follow-up: moderate improvement, tolerating quetiapine well
- Monitored for metabolic side effects with weight and glucose
Clinical Pearl: Bipolar depression differs from unipolar depression in treatment approach. Antidepressants carry risk of inducing mania or rapid cycling and should generally be avoided or used only with a mood stabilizer. First-line treatments for bipolar depression include quetiapine, lurasidone, lamotrigine, and the olanzapine-fluoxetine combination. Atypical features (hypersomnia, hyperphagia, leaden paralysis, rejection sensitivity) are more common in bipolar than unipolar depression and may suggest bipolarity in an undiagnosed patient.