F31 vs F33
F33 — Recurrent depressive disorder
Distinguish bipolar affective disorder from recurrent depressive disorder using the presence or absence of any documented elevated-pole (manic, hypomanic, or mixed) episode.
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Show overlap — what both share
Both categories can present with a current depressive episode of any severity, and both involve a course of more than one episode — recurrence by itself does not distinguish them.
Show decisive evidence
- F31 requires a documented elevated-pole (manic, hypomanic, or mixed) episode at some point in the person's history.
- F33 requires that no elevated-pole episode has ever occurred, however many depressive episodes there have been.
- Ordinary variation in mood, including a return to one's normal cheerful baseline personality between depressive episodes, is not evidence of an elevated-pole episode.
What weakens F31: A documented manic, hypomanic, or mixed episode, however brief or long ago, weakens F33 and favours F31, regardless of how many depressive episodes have also occurred.
Show duration / course
Both involve a course of multiple episodes; the distinguishing factor is the polarity of every episode in that course, not the number of episodes.
Show exclusions / context
A person's own or a family member's casual description of 'good days' or a 'cheerful side' should not be read as evidence of hypomania unless it meets hypomania's own threshold (a sustained, impairing-or-at-least-noticeable change from baseline, not simply their normal personality).
Show information still needed
Whether any period of impairing mood elevation, decreased need for sleep, or grandiosity has ever been documented, at any point in the person's history.
Show the common trap
Treating recurrence of depression, or occasional better days within a person's normal baseline personality, as sufficient evidence of bipolarity.
Mini challenge — practise this distinction
Apply the discriminating evidence above to a fresh case before checking the full feedback.