Depressive Disorder, Single Episode (ICD-11: 6A70) - Complete Coding Guide

1. Introduction

Depressive disorder, single episode, represents one of the most relevant mental health conditions in contemporary clinical practice. Characterized by the occurrence of a first depressive episode without prior history of similar episodes, this disorder affects millions of people worldwide, significantly impacting their quality of life, functionality, and overall well-being.

The clinical importance of this diagnosis lies not only in its considerable prevalence in the general population, but also in its potentially serious consequences when not properly identified and treated. The single depressive episode may arise at any phase of life, from adolescence to advanced age, and its presentation can vary considerably among different individuals.

From a public health perspective, depressive disorder represents one of the leading causes of functional disability globally. The economic impact is substantial, including direct costs with treatment and indirect costs related to loss of productivity, work absences, and reduced work capacity. Furthermore, there is a significant association with other medical conditions, complicating clinical management and increasing disease burden.

Correct coding using the ICD-11 system is critical for multiple reasons. First, it enables precise communication between health professionals, facilitating continuity of care. Second, it is essential for epidemiological purposes, enabling tracking of the prevalence and incidence of this disorder. Third, adequate coding directly impacts the reimbursement of medical services, the allocation of resources in health systems, and clinical research. Finally, the precise distinction between single and recurrent episode has important prognostic and therapeutic implications.

2. Correct ICD-11 Code

Code: 6A70

Description: Depressive disorder, single episode

Parent category: Depressive disorders

Official definition: Depressive disorder, single episode, is characterized by the presence or history of a depressive episode when there is no history of previous depressive episodes. A depressive episode is characterized by a period of depressed mood or diminished interest in activities that occurs for most of the day, nearly every day, for a period of at least two weeks, accompanied by other symptoms such as difficulty concentrating, feelings of worthlessness or excessive or inappropriate guilt, hopelessness, recurrent thoughts of death or suicide, changes in appetite or sleep, agitation or psychomotor retardation, and reduced energy or fatigue. There has never been any previous manic, hypomanic, or mixed episode, which would indicate the presence of a bipolar disorder.

This code belongs to the chapter of Mental, Behavioral, or Neurodevelopmental Disorders of ICD-11, specifically within the section of Mood Disorders. The hierarchical structure of the classification allows for additional specifiers to detail characteristics such as severity, presence of psychotic symptoms, and specific symptom patterns, providing more precise and clinically useful coding.

3. When to Use This Code

The code 6A70 should be used in specific clinical situations where all diagnostic criteria are present. Below are detailed practical scenarios:

Scenario 1: First depressive episode in young adult A 28-year-old female patient seeks care reporting persistent sadness, easy crying, and loss of interest in activities she previously enjoyed for approximately three months. She reports difficulty sleeping, loss of appetite with weight loss of about 5 kg, constant fatigue, and difficulty concentrating at work. She has no previous psychiatric history and has never experienced similar episodes before. There is no history of episodes of euphoria, hyperactivity, or impulsive behavior. The code 6A70 is appropriate.

Scenario 2: Depression following significant stressor event A 45-year-old male patient develops depressive symptoms after losing his job. The symptoms persist for more than three months after the initial stressor event, including daily depressed mood, marked anhedonia, insomnia, feelings of worthlessness, recurrent thoughts about death (without active suicidal ideation), and intense fatigue. The intensity and duration of symptoms exceed a normal adaptive response. There are no documented previous depressive episodes. The code 6A70 is appropriate, as the criteria for depressive episode are fully met, regardless of the initial stressor.

Scenario 3: Depression in elderly without psychiatric history A 72-year-old female patient, previously psychiatrically healthy, presents for the first time with depressive symptoms including profound sadness, loss of pleasure in social activities, sleep alterations with early morning awakening, decreased appetite, psychomotor retardation, and feelings of being a "burden" to the family. Symptoms have been present for two months. Careful evaluation rules out general medical conditions as the primary cause. This is clearly a first depressive episode, justifying the code 6A70.

Scenario 4: Depressive episode with melancholic features A 35-year-old male patient presents with a severe depressive episode characterized by complete anhedonia, morning worsening of symptoms, early morning awakening, significant psychomotor retardation, marked loss of appetite, and excessive guilt. There is no history of previous depressive episodes or manic or hypomanic symptoms. The code 6A70 with appropriate specifiers for melancholic features is correct.

Scenario 5: First depressive episode in postpartum context A 32-year-old woman develops severe depressive symptoms six weeks after delivery, including intense sadness, frequent crying, anhedonia, insomnia (beyond normal interruptions for baby care), feelings of inadequacy as a mother, and intrusive thoughts about possible harm to the baby (without actual intent). This is her first depressive episode. The code 6A70 is appropriate, with specifiers for peripartum onset if available.

Scenario 6: Depression with prominent somatic symptoms A 50-year-old male patient complains mainly of extreme fatigue, diffuse body pain, and memory problems. Extensive medical investigation rules out organic causes. Upon deeper history taking, depressed mood is revealed, along with anhedonia, sleep alterations, feelings of hopelessness, and difficulty concentrating present for three months. He has never presented with similar episodes before. The code 6A70 is appropriate, recognizing that somatic presentations are common in depressive disorders.

4. When NOT to Use This Code

Inappropriate use of code 6A70 can occur in several situations. It is fundamental to recognize when other codes are more appropriate:

Adjustment disorder: If depressive symptoms are clearly a response to an identifiable stressor, are proportional to the stressor, and do not meet the full criteria for a major depressive episode (for example, fewer symptoms or insufficient duration), the appropriate code would be for adjustment disorder. The critical distinction is that in adjustment disorder, symptoms are generally less severe and more directly related temporally to the stressor.

Bipolar disorder or related disorders: If there is a history of any manic, hypomanic, or mixed episode, even if it occurred years before, the correct diagnosis would be bipolar disorder, not depressive disorder single episode. It is essential to carefully investigate the complete psychiatric history, including periods of elevated mood, decreased need for sleep, increased energy, impulsive behavior, or excessive spending.

Recurrent depressive disorder: If the patient has already presented with one or more previous depressive episodes, the correct code would be 6A71 (recurrent depressive disorder), not 6A70. The distinction between single and recurrent episode is fundamental and has significant prognostic and therapeutic implications.

Dysthymic disorder: If depressive symptoms are chronic but of lesser intensity, persisting for at least two years, the appropriate diagnosis would be dysthymic disorder (6A72), not single depressive episode.

Depression secondary to medical conditions: If depressive symptoms are a direct physiological consequence of a general medical condition (for example, hypothyroidism, Parkinson's disease, cerebrovascular accident), the primary code should reflect the medical condition, with depression coded as secondary.

Normal grief: Although grief can include symptoms similar to depression, uncomplicated grief generally does not require coding as a depressive disorder. However, if symptoms are particularly severe, prolonged, or include specific features such as suicidal ideation or marked functional impairment, code 6A70 may be appropriate.

5. Coding Step by Step

Step 1: Assess diagnostic criteria

Confirmation of the diagnosis of depressive disorder, single episode, requires a comprehensive clinical evaluation. The professional must verify the presence of depressed mood or anhedonia (loss of interest or pleasure) as a central symptom, present most of the day, nearly every day, for at least two weeks.

Additionally, at least four of the following symptoms must be present: difficulty concentrating or indecisiveness; feelings of worthlessness or excessive or inappropriate guilt; hopelessness about the future; recurrent thoughts of death or suicidal ideation; significant changes in appetite or weight; changes in sleep (insomnia or hypersomnia); observable agitation or psychomotor retardation; and marked reduction in energy or fatigue.

Standardized assessment instruments may be helpful, including validated depression scales, structured interviews, and screening questionnaires. However, definitive diagnosis remains clinical, based on qualified professional judgment.

It is essential to assess the functional impact of symptoms, verifying whether there is significant impairment in social, occupational, or other important areas of life functioning. The evaluation should include investigation of suicide risk, associated psychotic symptoms, and comorbidities.

Step 2: Verify specifiers

Code 6A70 allows specifiers that provide important additional clinical information. Severity should be assessed as mild, moderate, or severe, based on the number of symptoms, their intensity, and the degree of functional impairment.

One should verify the presence of special features such as psychotic symptoms (delusions or hallucinations congruent or incongruent with mood), melancholic features (complete anhedonia, morning worsening, early morning awakening, marked psychomotor retardation), atypical features (mood reactivity, increased appetite, hypersomnia, sensation of heavy limbs), or prominent anxious features.

The temporal context may also be specified, such as peripartum onset (during pregnancy or in the first four weeks postpartum) or association with a seasonal pattern. These specifiers enrich the coding and guide therapeutic decisions.

Step 3: Differentiate from other codes

6A71: Recurrent depressive disorder - The fundamental difference is the presence of previous depressive episodes. If the patient has already experienced at least one prior depressive episode, even if it occurred years before and with complete recovery in the interval, the correct code is 6A71, not 6A70. This distinction is crucial because recurrent disorder has a higher risk of new episodes and often requires longer-term maintenance treatment strategies.

6A72: Dysthymic disorder - Characterized by chronic depressive symptoms of lesser intensity, persisting for at least two years. The symptoms are milder than in a major depressive episode, but are persistent. In depressive disorder, single episode (6A70), the symptoms are more intense, but episodic, with a relatively defined onset.

6A73: Mixed depressive and anxiety disorder - This code is used when depressive and anxious symptoms are present simultaneously, but neither set of symptoms is sufficiently severe or persistent to justify a separate diagnosis of depressive disorder or anxiety disorder. If the full criteria for a depressive episode are present, even with significant anxious symptoms, code 6A70 is more appropriate.

Step 4: Necessary documentation

Adequate documentation is essential to justify coding and ensure continuity of care. The clinical record should include:

• Detailed description of symptoms present, including duration, frequency, and intensity
• Confirmation of the absence of previous depressive episodes through careful psychiatric history
• Exclusion of previous manic, hypomanic, or mixed episodes
• Assessment of functional impact in social, occupational, and personal domains
• Suicide risk assessment and presence of psychotic symptoms
• Investigation of possible medical causes or substance-induced causes
• Applicable specifiers (severity, special features)
• Relevant medical and psychiatric comorbidities
• Proposed therapeutic plan and justification

This documentation not only supports coding but also facilitates communication between professionals and serves as a reference for future evaluations.

6. Complete Practical Example

Clinical Case:

Maria, 34 years old, teacher, seeks psychiatric care referred by her family physician. She reports that approximately three months ago she began feeling "different," initially attributing the symptoms to work stress. Progressively, she developed profound and persistent sadness, present practically every day, accompanied by complete loss of interest in activities she always enjoyed, such as reading, meeting friends, and practicing yoga.

Maria describes significant difficulty initiating sleep, frequently waking during the night and definitively waking at 4 AM, unable to fall back asleep. She reports loss of appetite with unintentional weight loss of approximately 6 kg. She feels constantly tired, even after nights when she manages to sleep somewhat more, and describes a sensation of "heaviness" that makes even simple tasks difficult.

At work, Maria has faced increasing difficulties with concentration, forgetting appointments and taking much longer to prepare her classes. She feels professionally inadequate and expresses feelings of guilt for "not being able to manage" her responsibilities. She reports recurrent thoughts that "it would be better not to be here," although she denies specific suicidal plans when directly questioned.

Maria denies substance use and does not present significant medical conditions. Recent laboratory tests, including thyroid function, were normal. She has never received psychiatric treatment previously and denies similar episodes in the past. When specifically questioned about periods of elevated mood, increased energy, or decreased need for sleep, she consistently denies such experiences.

Mental status examination reveals a patient with neat appearance but sad facial expression, poor eye contact, slowed speech with increased latencies, depressed mood, and restricted affect. There is no evidence of psychotic symptoms. Cognition is globally preserved, although with concentration difficulties. Insight is adequate and judgment is preserved.

Step-by-Step Coding:

Criteria Analysis:

1. Presence of depressed mood: Confirmed, present most of the day, almost every day, for three months

2. Anhedonia: Confirmed, complete loss of interest in previously pleasurable activities

3. Minimum duration of two weeks: Confirmed, symptoms present for three months

4. Additional symptoms present:

   • Insomnia with early morning awakening
   • Significant appetite alteration with weight loss
   • Fatigue and reduced energy
   • Difficulty concentrating
   • Feelings of worthlessness and excessive guilt
   • Recurrent thoughts about death
   • Psychomotor retardation (observed on examination)

5. Absence of previous depressive episodes: Confirmed by history

6. Absence of manic or hypomanic episodes: Confirmed by history

7. Significant functional impairment: Confirmed at work and in personal life

8. Not due to substances or medical condition: Confirmed

Code chosen: 6A70 - Depressive disorder, single episode

Applicable specifiers:

• Severity: Moderate to severe (based on number of symptoms, intensity, and functional impairment)
• Without psychotic features

Complete justification:

Code 6A70 is appropriate because the patient presents all diagnostic criteria for a major depressive episode: depressed mood and anhedonia as core symptoms, plus six additional symptoms (insomnia, appetite alteration, fatigue, difficulty concentrating, feelings of worthlessness/guilt, thoughts about death, psychomotor retardation), with duration exceeding two weeks and significant functional impairment.

Crucially, this is the first time the patient experiences such symptoms, with no history of previous depressive episodes, justifying the designation of "single episode." The absence of history of manic or hypomanic episodes excludes bipolar disorder. The severity and duration of symptoms exceed what would be expected in adjustment disorder, and the presentation is not consistent with persistent depressive disorder (which would be more chronic and less intense).

Complementary codes:

There is no need for additional codes in this specific case, although comorbidities, if present, should be coded separately.

7. Related Codes and Differentiation

Within the Same Category:

6A71: Recurrent depressive disorder

When to use 6A71 vs. 6A70: The code 6A71 should be used when the patient presents with a current depressive episode AND has a history of at least one previous depressive episode. The main difference is purely the presence of previous episodes. Whether this is the second, third, or tenth episode, the correct code is 6A71. The importance of this distinction lies in the fact that recurrent disorder has different prognostic implications, including higher risk of future new episodes and frequently requires longer maintenance treatment.

Main difference: Presence versus absence of previous depressive episodes in the patient's history.

6A72: Dysthymic disorder

When to use 6A72 vs. 6A70: Dysthymic disorder is characterized by chronic depressive symptoms of lower intensity that persist for at least two years. The symptoms are sufficient to cause discomfort, but do not meet the full criteria for major depressive episode. Use 6A72 when there is chronicity with lower intensity; use 6A70 when there is a more intense episode, but with a more defined onset and without a history of previous chronic depressive symptoms.

Main difference: Chronicity and symptom intensity - dysthymic is more chronic and less intense; single depressive episode is more intense and episodic.

6A73: Mixed depressive and anxiety disorder

When to use 6A73 vs. 6A70: This code is reserved for situations where depressive and anxiety symptoms coexist, but neither set of symptoms is sufficiently severe or numerous to justify a separate diagnosis of depressive disorder or anxiety disorder. If the full criteria for depressive episode are present (6A70), this is the primary diagnosis, even if significant anxiety symptoms are also present. 6A73 is essentially a category for "subsyndromal" presentations of both.

Main difference: Severity and completeness of diagnostic criteria - if the full criteria for depressive episode are present, use 6A70, not 6A73.

Differential Diagnoses:

Adjustment disorder with depressed mood: Can be confused with single depressive episode, especially when there is an identifiable stressor. The distinction is based on symptom severity and number. In adjustment disorder, symptoms are generally less numerous and intense, and there is a clearer temporal relationship with the stressor.

Bipolar disorder (depressive episode): Can be indistinguishable from a single depressive episode in the current presentation. The critical difference is the history: if there have been previous manic or hypomanic episodes, the diagnosis is bipolar disorder, not depressive disorder. Careful investigation of the history is essential.

Depression secondary to medical conditions: Conditions such as hypothyroidism, Parkinson's disease, multiple sclerosis, and others can cause depressive symptoms. Complete medical evaluation is necessary to exclude organic causes before coding as primary depressive disorder.

8. Differences with ICD-10

In ICD-10, the code equivalent to 6A70 would be F32 - Depressive episode. The ICD-10 structure used subdivisions based primarily on severity (F32.0 mild, F32.1 moderate, F32.2 severe without psychotic symptoms, F32.3 severe with psychotic symptoms).

The main changes in ICD-11 include a more dimensional and flexible approach to coding, with greater emphasis on specifiers that can be added to the base code. ICD-11 allows more detailed characterization of clinical features through multiple specifiers, rather than creating separate codes for each variation.

The terminology has also been updated for greater clarity and international consistency. ICD-11 uses "depressive disorder, single episode" instead of simply "depressive episode," making the distinction between single and recurrent episodes more explicit.

The practical impact of these changes includes greater diagnostic precision through the use of specifiers, improved international communication due to standardized terminology, and facilitation of transition between coding systems. Professionals who used ICD-10 need to familiarize themselves with the new specifier structure and with the subtle differences in diagnostic conceptualization.

ICD-11 also offers improved digital tools to assist in coding, including more intuitive navigation and enhanced search features, facilitating the identification of the correct code in daily clinical practice.

9. Frequently Asked Questions

How is the diagnosis of depressive disorder, single episode made?

The diagnosis is essentially clinical, based on a detailed interview with the patient. The mental health professional evaluates the presence of core symptoms (depressed mood and/or anhedonia) and additional symptoms, verifying that they are present for the necessary duration (at least two weeks) and causing significant functional impairment. The evaluation includes a complete psychiatric history to confirm that there have been no previous episodes. Standardized instruments can assist, but do not replace clinical judgment. Laboratory tests are frequently requested to exclude medical causes, but there is no specific test to confirm depression.

Is treatment available in public health systems?

In most countries, treatments for depressive disorders are available through public health systems, although accessibility and waiting times may vary significantly between different regions and systems. Treatment generally includes psychotherapy (particularly cognitive-behavioral therapy), antidepressant medication, or a combination of both. Community mental health services, outpatient clinics, and primary care professionals frequently offer initial assessment and treatment. In severe cases, hospitalization may be necessary and is generally available in public systems.

How long does treatment last?

The duration of treatment varies considerably among individuals. The acute phase of treatment, focused on symptom reduction, generally lasts 6 to 12 weeks. If there is adequate response, a continuation phase is recommended for at least 4 to 6 months after symptom remission to consolidate improvement and prevent early relapse. In single episode, after this period, treatment can often be discontinued gradually, although some patients may benefit from longer maintenance. Psychotherapy may continue for variable periods depending on individual needs and therapeutic goals.

Can this code be used in medical certificates?

Yes, the ICD-11 code 6A70 can be used in official medical documentation, including certificates. However, practices regarding what to include in certificates vary between different contexts. Some professionals prefer to use more general descriptions in documents that the patient will receive, while maintaining detailed coding in confidential medical records. It is important to balance the need for adequate documentation with patient privacy and preferences. In occupational contexts, it is often sufficient to indicate that the patient requires leave for medical reasons, without specifying the exact diagnosis.

What is the difference between normal sadness and clinical depression?

Sadness is a normal human emotion and an expected response to losses or disappointments. It is generally proportional to the precipitating event, improves gradually over time, and does not significantly impede daily functioning. Clinical depression, on the other hand, is characterized by more intense, numerous, and persistent symptoms that cause significant functional impairment. In depression, depressed mood is persistent (most of the day, nearly every day) and accompanied by multiple other symptoms. A person with depression frequently loses the ability to experience pleasure even in normally enjoyable activities, something that does not occur in normal sadness.

Do people with a single depressive episode always develop recurrent episodes?

No. Although there is a risk of recurrence, many people who experience a single depressive episode never develop another episode. Studies indicate that a significant proportion of individuals remains well after adequate treatment of a first episode. Factors that may influence the risk of recurrence include severity of the initial episode, presence of residual symptoms after treatment, family history of depression, age of onset, and presence of chronic stressors. Adequate and complete treatment of the first episode can reduce the risk of recurrence.

Is it possible to work or study during a depressive episode?

This depends on the severity of symptoms. In mild episodes, many people can maintain their activities, although with difficulty and reduced performance. In moderate to severe episodes, functional impairment may be significant, making it difficult or impossible to maintain normal performance at work or school. Some individuals may benefit from temporary adjustments, such as reduced hours or modification of responsibilities. In severe cases, temporary leave may be necessary to allow adequate treatment and recovery. The decision should be individualized, considering the severity of symptoms and the specific demands of work or study.

Do antidepressants cause dependence?

No, antidepressants do not cause dependence in the sense of creating compulsion for use or need for increasing doses to obtain the same effect. However, abrupt discontinuation can cause withdrawal symptoms in some cases, which is why withdrawal should be gradual and supervised. Antidepressants do not alter personality or cause euphoria. They work by correcting neurochemical imbalances associated with depression. It is important to distinguish physical dependence (which antidepressants do not cause) from discontinuation symptoms (which may occur with abrupt interruption, but are generally mild and transient when withdrawal is properly conducted).

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Conclusion:

Depressive disorder, single episode (ICD-11: 6A70), represents a significant clinical condition that requires precise identification and adequate treatment. Correct coding is essential not only for administrative and epidemiological purposes, but also to ensure effective communication between professionals and continuity of care. Understanding the diagnostic criteria, appropriate situations for use of this code, and its differentiation from related conditions is fundamental to quality clinical practice. With adequate treatment, the majority of individuals with a single depressive episode show significant improvement and many achieve complete remission, highlighting the importance of early recognition and appropriate intervention.

External References

This article was prepared based on reliable scientific sources:

1. 🌍 WHO ICD-11 - Depressive disorder, single episode
2. 🔬 PubMed Research on Depressive disorder, single episode
3. 🌍 WHO Health Topics
4. 📋 NICE Mental Health Guidelines
5. 📊 Clinical Evidence: Depressive disorder, single episode
6. 📋 Ministry of Health - Brazil
7. 📊 Cochrane Systematic Reviews

References verified on 2026-02-02