A 32-year-old man from Bangalore is evaluated after his partner noticed a 5-day period of unusually elevated mood, increased energy, and reduced sleep (sleeping 4–5 hours but feeling refreshed). During this time, he took on several new projects at work and made impulsive purchases online. He denies any psychotic symptoms. His past psychiatric history includes two major depressive episodes (one 3 years ago lasting 6 weeks, another 1 year ago lasting 4 weeks), both treated with sertraline. The current elevated mood episode started 2 days after he increased his sertraline dose for worsening depressive symptoms. There is no family history of bipolar disorder. What is the most likely diagnosis?

Explanation

## Diagnosis: Antidepressant-Induced Hypomania ### Clinical Features Analysis | Feature | Present | Interpretation | |---------|---------|----------------| | Elevated mood | Yes (5 days) | Meets duration for hypomania | | Decreased sleep | Yes (4–5 hrs, refreshed) | Consistent with hypomania | | Increased goal-directed activity | Yes (new projects, spending) | Typical of mood elevation | | Temporal relationship to SSRI dose increase | Yes (2 days) | **Critical: Temporal link to antidepressant** | | Psychotic features | No | Not present | | Prior manic episodes | No | Only depressive episodes | | Family history of bipolar disorder | No | Reduces bipolar likelihood | ### Distinguishing Antidepressant-Induced Hypomania from Bipolar II **Key Point:** The temporal relationship between antidepressant initiation/dose escalation and mood elevation is the **primary diagnostic clue**. Antidepressant-induced hypomania typically emerges within days of dose change, whereas spontaneous Bipolar II hypomanic episodes arise without clear iatrogenic trigger. **High-Yield:** Antidepressant-induced hypomania is **not counted as a bipolar episode** for diagnostic purposes. If the patient develops hypomania only during antidepressant therapy and has no spontaneous hypomanic episodes off medication, the diagnosis remains **unipolar depression**, not Bipolar II. ### Diagnostic Criteria Comparison ```mermaid flowchart TD A[Patient with Mood Elevation + Prior Depression]:::outcome --> B{Temporal relationship to antidepressant?}:::decision B -->|Clear temporal link to SSRI/SNRI initiation or dose increase| C[Antidepressant-Induced Hypomania]:::action B -->|No clear temporal link; spontaneous onset| D{Duration ≥7 days with severe impairment?}:::decision D -->|Yes| E[Bipolar Disorder I]:::action D -->|No, 4-6 days, no severe impairment| F[Bipolar Disorder II]:::action C --> G[Diagnosis: Unipolar Depression]:::outcome G --> H[Management: Reduce/discontinue antidepressant]:::action ``` ### Why This Is NOT Bipolar II 1. **Temporal trigger:** Hypomania began 2 days after sertraline dose increase—a clear iatrogenic cause. 2. **No spontaneous hypomanic episodes:** All prior mood episodes were depressive; no history of spontaneous hypomania off antidepressants. 3. **Duration borderline:** 5 days is at the lower threshold for hypomania (≥4 days); in the context of antidepressant exposure, this supports treatment-emergent rather than primary bipolar disorder. **Clinical Pearl:** Approximately 3–10% of patients treated with antidepressants for unipolar depression experience treatment-emergent hypomania or mania. This does **not** automatically convert the diagnosis to bipolar disorder; rather, it reflects antidepressant sensitivity and requires dose reduction or switch to mood stabilizer. ### Management Implications **Mnemonic: STOP-SSRI** — **S**witch or **T**aper **O**ff **P**SSRI, add mood stabilizer (lithium/valproate), **S**ubsequently **R**eassess **I**f mood stabilizes