F31 vs F34
F34 — Persistent mood [affective] disorders (cyclothymia)
Distinguish bipolar affective disorder from cyclothymia using whether either pole has ever reached full-episode severity.
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Show overlap — what both share
Both involve a pattern of mood swinging between elevation and depression over time, and a loosely described 'mood swings' history can superficially fit either.
Show decisive evidence
- F31 requires at least one documented episode reaching full manic, hypomanic, or mixed severity, with real functional impact or the fuller symptom cluster.
- F34 (cyclothymia) requires that neither the elevated nor the depressive swings ever reach full-episode severity, sustained over years.
- A single documented occasion of genuine functional impairment during an 'up' period (reckless spending, disrupted judgement) is enough to rule out cyclothymia and support a bipolar course instead.
What weakens F31: Any documented occasion where mood elevation or depression reached full-episode severity weakens F34 and favours F31, however mild the pattern looks the rest of the time.
Show duration / course
Both can span years, but F31 is defined by discrete episodes (of any frequency) that reach full severity, while F34 is defined by a continuous, low-grade pattern that never does.
Show exclusions / context
A vignette's own casual framing ('mood swings,' 'up and down') should not be taken at face value — each described period needs to be checked individually against the actual severity threshold.
Show information still needed
Whether any individual period of mood elevation or depression, however described, has ever involved genuine functional impairment or met a fuller symptom cluster.
Show the common trap
Accepting a chronic-sounding 'mood swings' history as cyclothymia without checking whether any individual period actually crossed into full-episode severity.
Mini challenge — practise this distinction
Apply the discriminating evidence above to a fresh case before checking the full feedback.