Bipolar I Disorder

Bipolar I Disorder is defined by the occurrence of at least one manic episode — that's it — and USMLE Step 1 tests it from multiple angles: pure definition and criteria recall, distinguishing mania from hypomania, managing acute mania (especially the antidepressant trap), and selecting the right maintenance agent based on clinical pattern. You don't need a depressive episode for the diagnosis, and that surprises a lot of students. The classic DIGFAST mnemonic covers the symptom criteria (Distractibility, Impulsivity/Indiscretion, Grandiosity, Flight of ideas, Activity increase, Sleep decrease, Talkativeness), and you need 3 of these if the mood is euphoric, or 4 if it's only irritable.

The trickiest part is where bipolar I intersects with MDD knowledge. Students who just finished learning MDD often anchor on the 2-week duration threshold and misapply it to mania — but a manic episode only requires 7 days, or less if the patient needs hospitalization. The exam loves to give you a stem where a patient is admitted involuntarily after 4 days of not sleeping and spending their savings, and you need to recognize that hospitalization alone satisfies the duration criterion. That's an application question, not a recall question, and it's where poorly-prepared students drop points.

Management questions are where USMLE Step 1 gets particularly clinical. The antidepressant-in-bipolar trap is one of the highest-yield misconceptions in all of psychiatry: giving an SSRI monotherapy to someone with unrecognized bipolar I is a classic wrong answer choice that looks superficially right. Separately, knowing when to pick lithium versus valproate for maintenance isn't about memorizing a table — it's about understanding what clinical features each drug handles better. Build those distinctions clearly and this topic becomes a reliable point-scorer.