The continuum of mood and mood disorder diagnosis

Mood refers to a person's emotional state, which can range from high levels of euphoria or mania to low levels of severe depression. Normally, mood fluctuates around a central, balanced point.

However, when a very high or very low mood persists for an extended period, it can disrupt daily functioning. In such cases, this may lead to a diagnosis of a mood disorder - a mental health condition characterised by significant and prolonged disturbances in mood that impair a person's ability to carry out normal activities, such as work, relationships, or self-care.

Understanding mood on a continuum helps explain that mood disorders are not sudden or isolated events but extreme shifts that dominate a person's emotional experience.

ICD-11 diagnostic criteria for depressive disorder

Depressive disorder, also known as unipolar depression, is a mood disorder marked by persistent low mood without episodes of high mood. The International Classification of Diseases (ICD-11), a global standard for diagnosing health conditions developed by the World Health Organization, provides specific criteria for identifying this disorder.

To meet the diagnosis, symptoms must be present most of the day, nearly every day, for at least two weeks, and they must cause significant distress or impairment.

Key symptoms of depressive disorder

• Depressed mood - Feeling sad, empty, or hopeless.
• Reduced interest in activities - Loss of pleasure in things previously enjoyed (anhedonia).
• Difficulty concentrating - Trouble focusing or making decisions.
• Feeling worthless - Low self-esteem or excessive self-criticism.
• Excessive or inappropriate guilt - Overwhelming feelings of blame for unrelated events.
• Hopelessness - A pervasive sense of despair about the future.
• Recurring thoughts of death or suicide - Frequent ideation about dying or self-harm.
• Changes in appetite or sleep - Significant weight loss/gain or insomnia/hypersomnia.
• Feeling agitated or slow movements - Restlessness or psychomotor retardation (slowed physical actions).
• Low energy or fatigue - Persistent tiredness despite rest.

ICD-11 diagnostic criteria for bipolar disorders

Bipolar disorders involve alternating periods of low and high mood, differing from unipolar depression by including manic episodes. Manic episodes are periods of abnormally elevated mood and energy. According to ICD-11, diagnosis requires at least one manic episode, often alternating with depressive episodes.

Symptoms can mix within the same week or even day, known as mixed episodes. Manic episodes must last at least one week, while depressive episodes follow similar criteria to depressive disorder but occur alongside mania.

Key symptoms of manic episodes in bipolar disorders

• Euphoria - An exaggerated sense of happiness or well-being.
• Irritability - Easily annoyed or agitated behaviour.
• Grandiosity - Inflated self-esteem or beliefs in one's superior abilities.
• Highly active - Increased goal-directed activity or restlessness.
• Subjective sense of increased energy - Feeling unusually energetic or invincible.
• Rapid speech - Talking quickly and excessively (pressured speech).
• Rapidly changing thoughts or ideas - Racing thoughts or flight of ideas.
• Decreased need for sleep - Feeling rested after little or no sleep.
• Easily distracted - Difficulty maintaining attention.
• Impulsive and reckless - Engaging in risky behaviours, such as excessive spending or unsafe actions.

Measuring depression with the Beck Depression Inventory

To assess the severity of depressive symptoms, tools like the Beck Depression Inventory (BDI) are used. The BDI is a psychometric test - a standardised measure of psychological attributes - designed to evaluate the intensity of depression symptoms.

It consists of 21 items, each scored from 0 to 3 based on the severity of the symptom experienced over the last two weeks. Higher total scores indicate more severe depression. The BDI is intended for use by qualified health professionals, not for self-diagnosis, to ensure accurate interpretation and appropriate follow-up.

How the BDI works

• Symptom coverage - Items address emotional, cognitive, and physical symptoms, such as sadness, guilt, or fatigue.
• Scoring system - Respondents choose statements that best describe their feelings, with scores added to categorise depression as minimal, mild, moderate, or severe.
• Purpose - It helps track changes in symptoms over time, making it useful for monitoring treatment progress.

Evaluating the diagnosis and measurement of mood disorders

Evaluating diagnostic tools like ICD-11 and measurement methods like the BDI involves assessing their strengths and weaknesses in terms of reliability, validity, and practicality. Reliability refers to consistency in results, while validity means the tool measures what it intends to.

Strengths and weaknesses of diagnostic and measurement tools

These evaluations highlight that while these tools are valuable, they must be used alongside clinical judgement to address their limitations.

Research study: Reed et al. (2018) on ICD-11 reliability

• Aim - This study examined the reliability of ICD-11 criteria for mood disorders.
• Method - Clinicians from various countries assessed patient vignettes (hypothetical case descriptions) using ICD-11 guidelines to diagnose disorders like bipolar and depressive types.
• Results - High inter-rater reliability (84%) for bipolar and recurrent depressive disorders, but lower (45%) for dysthymia.
• Conclusions - ICD-11 improves diagnostic consistency for major mood disorders but needs refinement for milder forms.
• Evaluation - Strengthens global applicability but reveals gaps in reliability for certain conditions.

Issues and debates: Cultural differences in mood disorders

Cultural factors influence how mood disorders are experienced and reported, affecting diagnosis and treatment. In low-to-middle-income countries (LMICs), individuals often express depression through somatic symptoms - physical complaints like aches and pains - rather than emotional or cognitive ones, such as feelings of emptiness or apathy.

This phenomenon is known as somatisation, where psychological distress manifests as bodily symptoms. ICD-11 acknowledges this variation, noting that people in LMICs may report physical issues more frequently.

Implications of cultural differences

• Diagnostic challenges - Western-focused tools like ICD-11 might miss somatic presentations, leading to underdiagnosis in diverse populations.
• Treatment approaches - Understanding cultural expressions can improve interventions, such as incorporating physical health checks in mental health assessments.
• Broader debate - This highlights how culture shapes mental health, supporting the need for culturally sensitive diagnostic criteria to avoid ethnocentric bias (favouring one culture's perspective).

Issues and debates: Individual versus situational explanations

Explanations for mood disorders can focus on individual factors - internal characteristics like thoughts, feelings, and behaviours - or situational factors - external events or circumstances.

ICD-11 primarily adopts an individual explanation, viewing mood disorders as differences in a person's internal state that lead to impaired functioning. This approach emphasises personal traits or biology as the root cause.

In contrast, situational explanations, such as the trauma-informed approach proposed by Johnstone (2018), stress external influences like adverse life events (e.g., abuse, loss, or stress) that contribute to mood disturbances. This perspective shifts focus from "what's wrong with the person" to "what happened to the person."

Comparing individual and situational explanations

• Individual focus - Useful for targeted therapies like medication or cognitive interventions, but may overlook environmental triggers.
• Situational focus - Promotes holistic support, such as addressing social inequalities, but might underplay biological vulnerabilities.
• Integrated view - Combining both can provide a more comprehensive understanding, recognising that individual differences interact with situations to produce mood disorders.

This debate encourages a balanced approach in psychology, considering both personal and contextual elements for effective diagnosis and treatment.