Category · F30-F39 block
F38 — Other mood [affective] disorders
Terminology note: F38 is a residual category for two specific presentations that fail the standard episode templates on a technicality that still matters: a first-ever episode with genuinely mixed manic and depressive features and no established bipolar course (F38.0), and recurrent depressive episodes that are real and impairing but each individually too brief to meet the two-week minimum duration (F38.1).
What is this category?
F38 exists because two genuine presentations do not fit anywhere else in this block. A mixed affective episode (F38.0) looks like F31.6 in symptom content, but F31.6 requires an already-established bipolar course, which a first-ever episode by definition does not have. Recurrent brief depressive disorder (F38.1) looks like F32/F33 in symptom content, but those categories require each episode to last at least two weeks, and these episodes, by definition, do not.
Core diagnostic concept
Both F38 subtypes are exception categories: the underlying disturbance is real and clinically significant, but it fails a specific structural requirement (an established prior course, or a minimum episode duration) that the standard episode categories require. Recognising F38 means recognising exactly which requirement is not met, not simply reaching for a residual code whenever a presentation feels atypical.
Key diagnostic features
- Mixed affective episode (F38.0)
- Manic and depressive symptoms occurring together or alternating very rapidly within the same episode, in a person with no prior manic, hypomanic, or depressive episode.
- Recurrent brief depressive disorder (F38.1)
- Depressive episodes recurring roughly monthly, each otherwise meeting the depressive symptom cluster but lasting only a few days — well under the two-week minimum.
How to weigh evidence
These learning labels are teaching aids, not official ICD-10 terminology (see Sources and Method).
- supports A first-ever episode showing marked elevation and marked depressive symptoms occurring simultaneously, with no prior episode of any kind.
- consistent not decisive Occasional very brief low mood lasting a single day now and then, without a clear recurring monthly pattern.
- raises alternative Mixed features occurring in a person with an already-documented bipolar course.
- contradicts or weakens Episodes that each last the full two weeks or more required for F32/F33.
- missing and necessary to ask The exact duration of each individual episode, and whether a bipolar course has already been established.
Diagnostic boundary
F38 covers mood presentations that fail a standard template on a specific technicality that still matters clinically — genuinely mixed features with no established bipolar course (F38.0), or recurrent depressive episodes too brief to meet the two-week minimum (F38.1).
Full comparisons:
Duration and course
Minimum duration: F38.0 follows the general duration conventions of a manic/depressive episode; F38.1 specifically involves episodes recurring roughly monthly, each lasting only a few days — well under two weeks.
Course: These are exception categories precisely because duration or course fails to fit the standard template while the underlying disturbance remains real and impairing.
Included presentations
- A first-ever episode with genuinely mixed manic and depressive features, no established bipolar course (F38.0).
- Recurrent depressive episodes, each lasting only a few days, recurring roughly monthly (F38.1).
Exclusions and distinguishing presentations
| If this is true instead… | Consider | Why |
|---|---|---|
| Mixed features occurring in a person with an already-established bipolar course | F31 | A mixed episode within a documented bipolar course is classified as F31.6, not F38.0. |
| Depressive episodes that individually last two weeks or more | F32 | Episodes meeting the standard duration threshold belong under F32, or F33 if recurrent, not F38.1. |
Four-character subtypes (orientation)
F38 should not be used as a general catch-all for 'doesn't quite fit' — check specifically whether the actual issue is an established bipolar course (favouring F31.6 instead) or standard-duration episodes (favouring F32/F33 instead) before settling on F38.
- F38.0 — Other single mood [affective] disorders
- A first-ever mixed affective episode, with no established bipolar course. (in_depth)
- F38.1 — Other recurrent mood [affective] disorders
- Recurrent brief depressive episodes, each lasting only a few days. (in_depth)
- F38.8 — Other specified mood [affective] disorders
- A mood presentation not matching the other listed subtypes. (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 — 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 — distinguishing a first mixed episode from mixed features within an established bipolar course
A 24-year-old, with no prior psychiatric history of any kind, presents with a one-week period during which she simultaneously feels profoundly hopeless and tearful while also talking rapidly, needing little sleep, and feeling unusually energetic — both sets of symptoms present together on the same days, not one after the other. No prior manic, hypomanic, or depressive episode has ever occurred.
- Step 1 — Note the simultaneous mixed presentation: depressive and manic symptoms co-occurring on the same days, not sequential episodes.
- Step 2 — Check for an established bipolar course: none — this is her first-ever episode of any kind.
- Step 3 — Apply the exception rule: genuinely mixed features without a prior bipolar course do not fit F30 (single-pole only), F31.6 (requires an established bipolar course), or F32 (single-pole only).
- Conclusion — F38.0, Other single mood disorders (mixed affective episode) — not F31.6, because no bipolar course has yet been established; a second episode of any kind would prompt reconsidering the classification.
Interactive practice
- Type A Tearful and wired, five days, first time ever Recognition / application · Core
- Type B A bad few days, once a month, for a year Boundary discrimination · Core
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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Explain the one structural requirement that separates a mixed affective episode (F38.0) from bipolar disorder, current episode mixed (F31.6).
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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State the maximum episode duration consistent with recurrent brief depressive disorder (F38.1).
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 F38 should not be used simply because a presentation feels atypical.
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
F38: F38 covers a first mixed episode with no established bipolar course (F38.0) and recurrent depressive episodes too brief to meet the two-week minimum (F38.1) — both real presentations that fail a specific structural requirement elsewhere in the block.
Decisive boundary cues:
- Mixed features plus no prior episode of any kind -> F38.0, not F31.6.
- Mixed features plus an already-documented bipolar course -> F31.6, not F38.0.
- Depressive episodes recurring monthly but lasting only a few days each -> F38.1, not F32/F33.
Duration/course: F38.1 episodes are well under the standard two-week minimum; this brevity is the defining feature, not an incidental detail.
Nearest alternatives: F31, F32, F33
Common mistake: Reaching for F38 as a general-purpose 'atypical presentation' code rather than checking the specific structural requirement (course history or episode duration) that is actually not met.
Retrieval prompt: Which specific requirement — an established prior course, or a minimum episode duration — is not met here?
(or use your browser's print function) Open full-page printable revision view →
Related glossary terms
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Mixed affective episode
An episode in which manic and depressive symptoms occur together or alternate very rapidly within the same episode, rather than one pole cleanly followed by the other. Classified as F31.6 when it occurs within an already-established bipolar course, or F38.0 when it is a first-ever episode with no such course yet documented.
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.