Category · F30-F39 block
F33 — Recurrent depressive disorder
Terminology note: "Recurrent" here means at least two separate depressive episodes, each individually meeting F32's own duration/severity threshold, separated by an interval of substantially normal mood — with no manic, hypomanic, or mixed episode ever documented. Any such elevated-pole episode, at any point, reclassifies the course as bipolar (F31), however many depressive episodes have occurred.
What is this category?
F33 asks two separate questions, in order: first, has this person had at least two genuinely separate depressive episodes, with no elevated-pole episode ever documented (the course question, which is what makes this F33 rather than F32 or F31); second, what is the severity of the current episode, or is the person currently in remission (a legitimate, separately coded current state, not 'no diagnosis').
Core diagnostic concept
Recurrence of depression, however many episodes and however long the history, never by itself implies bipolarity — that requires a genuine elevated-pole (manic, hypomanic, or mixed) episode to have occurred, which is a distinct and separate question from how many depressive episodes there have been. Ordinary variation in mood — including brief 'better' stretches within a person's normal baseline personality — is not evidence of hypomania and does not change a recurrent depressive course into a bipolar one.
Key diagnostic features
- At least two documented depressive episodes
- Each individually meeting the core-plus-additional symptom and duration criteria for a depressive episode.
- Substantially normal mood between episodes
- A meaningful interval — typically some months — of largely restored mood and functioning separating genuinely distinct episodes.
- No elevated-pole episode ever documented
- The decisive feature separating F33 from F31: no manic, hypomanic, or mixed episode has ever occurred, at any point.
- Remission as a legitimate current state
- A person with a documented recurrent course who is not currently symptomatic is coded as currently in remission (F33.4), not treated as free of the diagnosis.
How to weigh evidence
These learning labels are teaching aids, not official ICD-10 terminology (see Sources and Method).
- supports A documented second (or later) depressive episode, with a clear prior episode and substantial recovery between them, and no elevated-pole episode ever.
- consistent not decisive A person reports feeling 'low sometimes,' without a clearly demarcated, threshold-meeting second episode having been established.
- raises alternative A genuinely elevated period — impairing, with decreased need for sleep and grandiosity — reported alongside the depressive episodes.
- contradicts or weakens Only one depressive episode has actually been documented so far, however severe.
- missing and necessary to ask Whether any hypomanic or manic episode, however brief or mild, has ever occurred — the single most decisive fact against F31.
Diagnostic boundary
F33 requires at least two depressive episodes with no elevated-pole episode ever documented; current severity or remission sets the fourth character. Any confirmed elevated-pole episode, at any point, reclassifies the course as bipolar (F31) instead.
Full comparisons:
Duration and course
Minimum duration: Each episode individually follows F32's own duration threshold (typically at least two weeks); episodes are conventionally separated by an interval of at least a couple of months of substantially normal mood.
Course: The number and severity of episodes vary widely between individuals; recovery between episodes is often, but not always, fairly complete.
Included presentations
- Recurrent depressive disorder, current episode mild or moderate.
- Recurrent depressive disorder, current episode severe, with or without psychotic symptoms.
- Recurrent depressive disorder, currently in remission.
Exclusions and distinguishing presentations
| If this is true instead… | Consider | Why |
|---|---|---|
| Only one depressive episode documented so far | F32 | A single episode without recurrence is classified as a depressive episode, not recurrent depressive disorder. |
| Any documented manic, hypomanic, or mixed episode at any point | F31 | A confirmed elevated-pole episode establishes a bipolar course rather than recurrent depressive disorder. |
| Persistent, subthreshold low mood lasting years without ever meeting full episode severity | F34 | A chronic subthreshold pattern is dysthymia, not a series of discrete full-threshold episodes. |
Four-character subtypes (orientation)
Severity grading for the current episode follows the same principles already taught in depth under F32 and is not repeated here. This category's own distinctive teaching focus is the recurrence requirement itself and remission as a legitimate, separately coded current state — not a return to 'no diagnosis.'
- F33.0 — Recurrent depressive disorder, current episode mild
- Recurrent course, current episode of mild severity. (taught for orientation only, not separately assessed in this pilot)
- F33.1 — Current episode moderate
- Recurrent course, current episode of moderate severity. (taught for orientation only, not separately assessed in this pilot)
- F33.2 — Current episode severe without psychotic symptoms
- Recurrent course, current episode severe, without delusions or hallucinations. (taught for orientation only, not separately assessed in this pilot)
- F33.3 — Current episode severe with psychotic symptoms
- Recurrent course, current episode severe, with mood-congruent delusions or hallucinations. (taught for orientation only, not separately assessed in this pilot)
- F33.4 — Currently in remission
- Recurrent course documented, no significant current mood disturbance. (in_depth)
- F33.8 — Other recurrent depressive disorders
- A recurrent depressive presentation not matching the other listed subtypes. (taught for orientation only, not separately assessed in this pilot)
- F33.9 — Recurrent depressive disorder, unspecified
- A recurrent depressive course identified but without enough information to specify the current state further. (taught for orientation only, not separately assessed in this pilot)
External causes to check first
Categories in this block require that the disturbance is not better explained by another external cause listed below. These short capsules are reminders, not full teaching modules.
External cause capsule — Affective disorders with psychotic features
A reminder to check whether psychotic symptoms are confined to, and explained by, a manic or depressive episode, before applying F20 or F25.
What to check:
- Whether psychotic symptoms (e.g. mood-congruent delusions of guilt or grandiosity) appear only during a clearly established manic or depressive episode and resolve as the mood episode resolves.
- Whether mood symptoms clearly preceded the psychotic features, or vice versa.
- Whether the delusional content is mood-congruent (fitting the prevailing mood, e.g. grandiose ideas during mania) rather than the more mood-neutral or bizarre content typical of F20.
- Whether this pattern has recurred across more than one episode, which would raise consideration of F25 rather than a simple mood disorder with psychotic features.
The full F30-F39 category pages (F30, F31, F32, F33) themselves, which cover the severity-and-psychotic-features gradient for manic and depressive episodes in depth; this capsule is a focused reminder of the boundary against F20/F25, not a substitute for those pages.
External cause capsule — Organic, medical, or substance-related mood presentations
A reminder that a manic or depressive presentation can be caused by a general medical condition (e.g. thyroid disease, stroke) or by a substance or medication (e.g. corticosteroids, stimulant intoxication, sedative/alcohol withdrawal) rather than being a primary F30-F39 mood disorder, and that this should be actively considered before a primary mood-disorder classification is settled.
What to check:
- Timing: did the mood symptoms begin during or shortly after starting, stopping, intoxication with, or withdrawal from a substance or medication known to affect mood?
- Medical context: is there a known medical condition (e.g. thyroid disease, corticosteroid treatment, a neurological condition) with a recognised association with mood disturbance?
- Course after the cause is addressed: a mood presentation that substantially improves once the medical condition is treated or the substance/medication is stopped weighs toward a secondary cause rather than a primary mood disorder.
- Whether mood symptoms clearly predated the medical condition, substance use, or medication in question, which would argue against a purely secondary explanation.
A full teaching module on F10-F19 (substance-related disorders) or a general medical work-up, both of which are outside this capsule's scope.
Worked example — checking for any elevated-pole history before confirming a recurrent depressive course
A 52-year-old woman has had three separate depressive episodes over the past six years, each lasting six to ten weeks, with extended periods of essentially normal mood and functioning between them. During those between-episode periods, she describes herself as 'back to my normal, upbeat self' for a week or two before settling into her usual baseline — nothing beyond her ordinary personality. No episode of impairing elevated mood, decreased need for sleep, or grandiosity has ever been documented. She currently reports two weeks of low mood, poor sleep, and reduced appetite, meeting criteria for a mild depressive episode.
- Step 1 — Count episodes: three documented depressive episodes over six years, separated by extended intervals of normal mood, establishes recurrence.
- Step 2 — Check elevated-pole history: the 'upbeat' between-episode periods are described as a return to her ordinary baseline personality, not a distinct, impairing elevation with decreased sleep need or grandiosity — hypomania's threshold is not met.
- Step 3 — Grade the current episode: two weeks, meeting the mild depressive-episode threshold.
- Step 4 — Assign the current-state fourth character: since she is currently symptomatic, the current mild episode is coded, not remission.
- Conclusion — F33.0, Recurrent depressive disorder, current episode mild — not F31, because no genuine elevated-pole episode has ever been documented; the between-episode 'upbeat' periods are ordinary variation within her normal baseline, not hypomania.
Interactive practice
- Type A A second episode, four years apart Recognition / application · Foundation
- Type B "She has good days too, so it's probably bipolar" Boundary discrimination · Transfer
Retrieval prompts
Try answering each of these from memory before revealing where to check. Nothing you think or type here is sent or saved anywhere.
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State the two separate questions that must both be answered before assigning an F33 fourth character.
Reveal answer location
Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.
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Explain why an 'upbeat week' within a person's ordinary baseline personality does not, by itself, establish hypomania.
Reveal answer location
Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.
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Explain why remission is coded as a distinct current state (F33.4) rather than treated as no longer having the disorder.
Reveal answer location
Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.
These self-checks are a personal study aid only, visible to you on this page for this visit — they are not stored and do not affect your mastery dimensions.
Rapid revision card
F33: F33 requires at least two depressive episodes with no elevated-pole episode ever documented; current severity or remission sets the fourth character, and any confirmed elevated-pole episode reclassifies the course as bipolar instead.
Decisive boundary cues:
- Two or more depressive episodes, no elevated-pole episode ever -> weighs toward F33.
- Any documented manic, hypomanic, or mixed episode, however brief -> weighs toward F31 instead.
- Ordinary 'better' stretches within the person's normal baseline personality -> not evidence of hypomania by itself.
Duration/course: Episodes typically separated by an interval of at least a couple of months of substantially normal mood.
Nearest alternatives: F31, F32, F34
Common mistake: Treating recurrence of depression, or occasional better days, as evidence of bipolarity without checking for a genuine, threshold-meeting elevated-pole episode.
Retrieval prompt: Has a genuinely impairing elevated-mood episode — not just a good day — ever been documented for this person?
(or use your browser's print function) Open full-page printable revision view →
Related glossary terms
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Hypomania
A milder, sustained elevation of mood and increased activity that is a clear change from a person's usual baseline, but without the marked functional impairment, need for hospitalisation, or psychotic features that would make it mania.
Source basis
WHO ICD-10 international classification structure and code/title (ICD-10 Browser, 2019 English release).
Original educational synthesis, informed by general published clinical-education understanding of ICD-10 F30-F39; no verbatim CDDG or DCR text is reproduced. See Sources and Method for the full policy.
Last reviewed: 2026-09-16. Full policy: Sources and Method.
Educational resource only. This page and its cases teach ICD-10 classification reasoning using fictional scenarios. It does not diagnose real people and should not be used to assess yourself or anyone else. If you or someone you know may be experiencing a mood episode, or is at risk of harming themselves, please seek prompt professional evaluation.