Bipolar I Disorder
A patient with full-blown manic episodes (extreme highs lasting ≥7 days) and major depressive episodes (extreme lows) has Bipolar I disorder, not Bipolar II disorder. The defining feature is the presence of at least one true manic episode—Bipolar I requires only mania for diagnosis, while depression (though common) is not required 1, 2.
Key Diagnostic Distinction
Bipolar I disorder is diagnosed based on the occurrence of at least one manic or mixed episode lasting ≥7 days (or requiring hospitalization), regardless of whether depressive episodes occur 2. In contrast, Bipolar II disorder requires both major depressive episodes AND hypomanic episodes (milder, lasting ≥4 days), with no history of full manic episodes 1, 2, 3.
The critical differentiator is mania versus hypomania:
Mania (Bipolar I): Marked euphoria, grandiosity, or severe irritability with reduced sleep need, racing thoughts, pressured speech, and excessive goal-directed activity or risk-taking, causing marked impairment in functioning or requiring hospitalization 1, 2
Hypomania (Bipolar II): Similar symptoms but less severe, lasting ≥4 days, without marked impairment or need for hospitalization 1, 2
Clinical Presentation of "Extreme Highs and Lows"
When a patient describes "extreme highs," this language typically indicates full manic episodes rather than hypomania 4, 5. True mania represents:
- A significant departure from baseline functioning that is evident and impairing across multiple life domains, not isolated to one setting 1
- Associated psychomotor, sleep, and cognitive changes accompanying the mood disturbance 1
- Often includes psychotic features such as paranoia, confusion, or florid psychosis 1
The "extreme lows" in Bipolar I disorder commonly feature:
- Psychomotor retardation and hypersomnia 1
- High suicidality with significant suicide attempts 1
- Psychotic features are often present 1
Prevalence of Depression in Bipolar I
Most Bipolar I patients experience major or minor depressive episodes during their lifetime, even though depression is not required for diagnosis 1, 2. In fact, depressive episodes and symptoms dominate the longitudinal course and disproportionately account for morbidity and mortality in bipolar disorders 4. However, the presence of even one manic episode establishes the diagnosis of Bipolar I disorder 2, 4.
Common Diagnostic Pitfalls
Bipolar II disorder is frequently misdiagnosed as unipolar major depressive disorder because patients with Bipolar II present with recurrent depressive episodes that outnumber hypomanic episodes by a ratio of 39:1 3. However, this is not your scenario—your patient has full mania, which rules out Bipolar II entirely.
Do not confuse irritability or agitation with mania—true manic grandiosity and irritability present as marked changes in mental and emotional state, not reactions to situations 1. Use a life chart to characterize the longitudinal course and verify that episodes represent departures from baseline across multiple settings 1.
Verify episode duration carefully: Hypomanic episodes require ≥4 days, while manic episodes require ≥7 days (unless hospitalization is needed) 1, 2. Episodes lasting less than 4 days do not meet criteria for either and should be classified as Bipolar Disorder Not Otherwise Specified 1.
Treatment Implications
The distinction matters for treatment planning:
- Bipolar I disorder typically requires mood stabilizers (lithium is the gold standard) and/or atypical antipsychotics for acute mania and maintenance 4, 5
- Antidepressant monotherapy should be avoided in established Bipolar I disorder, as it is associated with mood destabilization, especially during maintenance treatment 4, 6
- Lamotrigine is effective for treating and preventing bipolar depression 4