Depression is often misunderstood as mere sadness or a fleeting blue mood. In reality it is a complex and debilitating mental health condition that affects millions worldwide. The World Health Organisation’s International Classification of Diseases 11th Revision (ICD-11) provides a comprehensive framework for diagnosing and understanding depressive episodes, distinguishing them from everyday fluctuations in mood.
Table of Contents
- Diagnostic process
- The ICD-11 Criteria
- Severity
- Context of Depressive Episodes in Bipolar Disorders
- Conclusion
The ICD-11 emphasises that a depressive episode is not simply feeling down. It is a persistent state characterised by a cluster of emotional, cognitive, behavioural, and physical symptoms that significantly impair an individual’s ability to function in their daily life.
One of the most pervasive misconceptions about depression is that it is a sign of weakness or a character flaw. In reality, depression is a medical condition, often rooted in a complex interplay of biological, psychological, and social factors. It is important to dispel this stigma and recognise that seeking help for depression is a sign of strength, not weakness. Another common misconception is that people with depression can simply “snap out of it” or “cheer up.” Depression is not a choice; it is a serious illness that requires professional treatment and support.
By understanding the true nature of depression, we can foster empathy, reduce stigma, and empower individuals to seek the help they need to reclaim their lives.
This article does not cover treatment of depressive episodes or bipolar disorders. Treatment will be covered separately in other articles.
Diagnostic process
The diagnostic criteria provided in the ICD-11 for a depressive episode offer a structured framework for identifying and assessing the key symptoms and their impact on an individual’s life. However, it is crucial to emphasise that diagnosis is not a simple checklist exercise. The criteria should be interpreted and applied within the context of a comprehensive clinical assessment conducted by a qualified mental health professional.
The process involves a careful exploration of the individual’s presenting symptoms, their duration and severity, and the impact on their overall functioning. It also requires considering other potential causes for the symptoms, such as medical conditions or substance use, to ensure an accurate diagnosis. The expertise of a mental health professional is essential in navigating the complexities of the diagnostic process, recognising the nuances of individual experiences, and tailoring treatment plans to meet the specific needs of each person.
Diagnostic screening
The PHQ9 is commonly used in the NHS especially among GP practices in the UK. There is evidence the author has seen, where it is used as a diagnostic instrument. This is fundamentally wrong. The inappropriate use the PHQ9 is due to high pressure on various services to perform and a failure of inspectorate processes.
The PHQ-9’s limitations, especially its reliance on self-reporting and susceptibility to subjective interpretation, can indeed contribute to the risk of over-diagnosis or misdiagnosis of depression if used inappropriately.
- Over-diagnosis: The PHQ-9’s sensitivity to various emotional states and life stressors can lead to false positives, where individuals experiencing temporary sadness or situational difficulties might be flagged as potentially depressed. This could result in unnecessary labelling, stigma, and potentially harmful interventions.
- Misdiagnosis: The PHQ-9’s focus on core depressive symptoms might lead to overlooking other mental health conditions or underlying medical issues that present with similar manifestations. This could delay appropriate treatment and exacerbate the individual’s suffering.
No reasonable person would tolerate the idea of people being hurriedly and incorrectly diagnosed for something like gall-bladder problems or breast cancer. Why this sort of thing is being tolerated in mental health services, is bewildering. But let us avoid distraction.
| Pros | Cons |
|---|---|
| Accessibility and Ease of Use: | Self-Report Bias: |
| * Simple and quick to administer, requiring minimal training. | * Relies on the patient’s self-assessment, which can be influenced by various factors (e.g., understanding of questions, willingness to disclose, current emotional state). |
| * Can be completed by the patient themselves or with assistance. | * May lead to underreporting or overreporting of symptoms. |
| * Can be used in various settings (primary care, mental health clinics, research). | |
| Standardisation and Quantification: | Limited Scope: |
| * Provides a standardised measure of depressive symptom severity. | * Focuses primarily on core depressive symptoms and may not capture the full complexity of the individual’s experience. |
| * Allows for tracking changes in symptoms over time. | * May not consider other potential contributing factors (e.g., medical conditions, life stressors). |
| * Facilitates communication between healthcare providers. | |
| Sensitivity and Specificity: | Potential for Misinterpretation: |
| * Demonstrates good sensitivity in detecting depression, particularly at higher cut-off scores. | * A high score may indicate depression but could also be indicative of other mental health conditions or medical issues. |
| * Can aid in identifying individuals who require further evaluation. | * Requires clinical judgment and additional assessment to confirm a diagnosis. This is a con because finding someone qualified to do furhter assessment is a big problem. Therefore it becomes easier to prescribe whilst waiting 6 months or so for assessement. |
| Risk of Over-diagnosis or Misdiagnosis: | |
| * Over-reliance on the PHQ-9 can lead to labelling individuals with temporary sadness or situational difficulties as depressed. | |
| * May overlook other mental health conditions or underlying medical issues presenting with similar symptoms. |
It is essentail for healthcare professionals to exercise caution and clinical judgment when utilizing the PHQ-9. It should be seen as a preliminary screening tool that warrants further investigation, rather than a definitive diagnostic instrument. Combining it with a thorough clinical interview, consideration of the individual’s context and history, and potentially other assessments can help mitigate the risk of over-diagnosis and misdiagnosis, ensuring that people receive accurate and appropriate care for their specific needs.
Available is the the Depressive Episode Checker created by the author is based heavilty on ICD-11 (the latest) diagnostic criteria.
The ICD-11 Criteria
The criteria are all taken from ICD-11 for educational purposes.
The concurrent presence of at least five of the following characteristic symptoms occurring for most of the day, nearly every day, during a period lasting at least 2 weeks is required for diagnosis.
At least one symptom from the affective cluster must be present. Assessment of the presence or absence of symptoms should be made relative to typical functioning of the individual.
Affective cluster
- Depressed mood as reported by the individual (e.g. feeling down, sad) or as observed (e.g. tearful, defeated appearance) (Note: in children and adolescents depressed mood can manifest as irritability.)
- Markedly diminished interest or pleasure in activities, especially those normally found to be enjoyable to the individual (Note: this may include a reduction in sexual desire.)
Cognitive-behavioural cluster
- Reduced ability to concentrate and sustain attention on tasks, or marked indecisiveness
- Beliefs of low self-worth or excessive and inappropriate guilt that may be manifestly delusional (Note: this item should not be considered present if guilt or self-reproach is exclusively about being depressed.)
- Hopelessness about the future
- Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation (with or without a specific plan), or evidence of attempted suicide
Neurovegetative cluster
- Significantly disrupted sleep (delayed sleep onset, increased frequency of waking during the night, or early morning awakening) or excessive sleep
- Significant change in appetite (diminished or increased) or significant weight change (gain or loss)
- Psychomotor agitation or retardation (observable by others, not merely subjective feelings of restlessness or being slowed down)
- Reduced energy, fatigue or marked tiredness following the expenditure of only a minimum of effort
Exclusion criteria
- The symptoms are not better accounted for by bereavement.
- The symptoms are not a manifestation of another medical condition (e.g. a brain tumour), and are not due to the effects of a substance or medication on the central nervous system (e.g. benzodiazepines), including withdrawal effects (e.g. from stimulants).
- The clinical presentation does not fulfil the diagnostic requirements for a mixed episode.
- The mood disturbance results in significant impairment in personal, family, social, educational, occupational or other important areas of functioning. If functioning is maintained, it is only through significant additional effort
The exclusion criteria are not to be treated lightly.
Severity
Mild depressive episode
- None of the symptoms of a depressive episode should be present to an intense degree.
- The individual is usually distressed by the symptoms, and has some difficulty in continuing to function in one of more domains (personal, family, social, educational, occupational or other important domains).
- There are no delusions or hallucinations during the episode.
Moderate depressive episode with or without psychotic symptoms
Several symptoms of a depressive episode are present to a marked degree, or a large number of depressive symptoms of lesser severity are present overall.
The individual typically has considerable difficulty functioning in multiple domains (personal, family, social, educational, occupational or other important domains).
There are delusions or hallucinations during the episode. [If no psychotic symptoms then code appropriately as ‘without’.]
Severe depressive episode without psychotic symptoms
Many or most symptoms of a depressive episode are present to a marked degree, or a smaller number of symptoms are present and manifest to an intense degree.
The individual has serious difficulty continuing to function in most domains (personal, family, social, educational, occupational or other important domains).
There are no delusions or hallucinations during the episode. [If no psychotic symptoms then code appropriately as ‘without’.]
Context of Depressive Episodes in Bipolar Disorders
The presence of depressive episodes in both Bipolar I and Bipolar II disorders underscores the complexity and overlapping nature of these conditions. While the defining feature of Bipolar I is the occurrence of manic episodes, individuals with this disorder also frequently experience depressive episodes, which can be equally debilitating and contribute significantly to the overall burden of the illness. In contrast, Bipolar II disorder is characterised by the presence of both hypomanic and major depressive episodes, with the latter often being more prominent and causing significant impairment in functioning. The shared presence of depressive episodes in these disorders highlights the importance of careful assessment and differential diagnosis to ensure appropriate treatment and support for individuals experiencing mood swings.
| Criteria | Bipolar I Disorder | Bipolar II Disorder | Depressive Episode |
| Primary Diagnostic Features | At least one manic episode, with or without depressive or hypomanic episodes. | At least one hypomanic episode and one major depressive episode. No manic episodes. | One or more depressive episodes, with no history of mania or hypomania. |
| Severity of Manic Symptoms | Manic episodes involve severe symptoms causing marked impairment in social or occupational functioning. May require hospitalisation. | Hypomanic episodes involve less severe symptoms and do not cause marked impairment. No hospitalisation required. | Not applicable, as no mania or hypomania is present. |
| Depressive Symptoms | May include depressive episodes, but not required for diagnosis. | Includes major depressive episodes. | Core feature: at least one episode of significant depressive symptoms. |
| Hypomanic Symptoms | Not required, but hypomanic episodes may occur between or before manic episodes. | Required: at least one hypomanic episode. | Not present. |
| Chronicity | Chronic, with episodes of mania, hypomania, or depression potentially recurring over time. | Chronic, with recurrent episodes of hypomania and depression. | Episodic, with one or more periods of depressive episodes. |
| Hospitalisation Risk | High during manic episodes due to severity and potential for psychosis. | Lower than Bipolar I, as hypomanic episodes are less severe and do not typically require hospitalisation. | May require hospitalisation if depressive symptoms are severe. |
| Psychosis Risk | Possible during manic episodes, especially in severe cases. | Less common, but possible during depressive episodes if severe. | Possible in severe depressive episodes. |
| Suicide Risk | Elevated, particularly during depressive or mixed episodes. | Elevated, particularly during depressive episodes. | Elevated, particularly in severe depressive episodes. |
| Impact on Functioning | Significant impairment during manic episodes; varying during other episodes. | Impairment primarily during depressive episodes; functioning may be improved during hypomania. | Impairment primarily during depressive episodes. |
| Treatment Considerations | Requires mood stabilisers, antipsychotics, and sometimes antidepressants. | Focus on mood stabilisers, with careful use of antidepressants. | Primarily antidepressants and psychotherapy. |
| Diagnosis Exclusion | Excludes any other primary mood disorder diagnosis. | Excludes any history of manic episodes. | Excludes any history of manic or hypomanic episodes. |
The accuracy of diagnosing bipolar disorders, particularly Bipolar II, hinges significantly on the accurate identification of depressive episodes. The core distinction between Bipolar I and Bipolar II lies in the presence of manic versus hypomanic episodes, respectively. However, both disorders share the common feature of depressive episodes.
The challenge arises in differentiating between a unipolar depressive disorder and Bipolar II disorder, as both can present with major depressive episodes. The key differentiator is the presence of hypomanic episodes in Bipolar II. If a hypomanic episode is missed or misdiagnosed, it can lead to an inaccurate diagnosis of unipolar depression, potentially delaying appropriate treatment and increasing the risk of future mood instability.
The perception that Bipolar II is a less severe syndrome compared to Bipolar I is generally true but requires some nuance. The primary reason for this perception is that Bipolar II does not involve full-blown manic episodes, which are a hallmark of Bipolar I and can lead to severe impairment, hospitalisation, and even psychosis. In contrast, Bipolar II is characterised by hypomanic episodes, which are less intense and typically do not cause the same level of disruption.
However, it is important to recognise that Bipolar II is not without its challenges. The depressive episodes experienced in Bipolar II can be just as severe and long-lasting as those in Bipolar I, leading to significant distress and impairment. Additionally, the rapid cycling between hypomania and depression in Bipolar II can be destabilising and difficult to manage.
Therefore, while Bipolar II may be considered less severe in terms of the intensity of manic symptoms, it is important to acknowledge the significant impact it can have on an individual’s life and well-being. Both Bipolar I and Bipolar II are serious mental health conditions that require comprehensive treatment and support.
Conclusion
The ICD-11 provides a detailed framework for diagnosing depressive episodes, emphasising the presence of a cluster of emotional, cognitive, behavioural, and physical symptoms that significantly impair an individual’s daily functioning. The criteria highlight the importance of a comprehensive clinical assessment by a mental health professional, going beyond a simple checklist approach, to ensure an accurate diagnosis and appropriate treatment plan. The discussion also touched upon the critical role of accurately diagnosing depressive episodes in the context of bipolar disorders, particularly Bipolar II, where distinguishing between unipolar depression and Bipolar II hinges on identifying hypomanic episodes alongside depressive ones.
The distinction between Bipolar I and Bipolar II was also explored, with Bipolar I characterised by manic episodes and Bipolar II by hypomanic episodes. While Bipolar II is generally considered less severe due to the absence of full-blown manic episodes, it is crucial to recognise the significant impact of depressive episodes in both disorders. The potential for severe and long-lasting depression in Bipolar II, coupled with the challenges of rapid cycling between hypomania and depression, underscores the need for comprehensive treatment and support for individuals with either diagnosis.
Finally, the exploratoin emphasised that diagnosing mental health conditions, especially complex ones like bipolar disorders, is not a straightforward process. It requires the expertise of trained professionals who can carefully interpret diagnostic criteria, consider individual nuances, and rule out other potential causes for symptoms. The accurate identification of depressive episodes is paramount in this process, as it can significantly impact the course of treatment and the overall well-being of individuals experiencing mood disorders.
