Mental Health Disorder Diagnosis and Classification (Edexcel A-Level Psychology): Revision Notes

Mental Health Disorder Diagnosis and Classification

The four 'Ds' of diagnosis

When clinicians assess whether a behaviour is abnormal and requires clinical diagnosis and treatment, they typically evaluate four key dimensions. These dimensions help determine if a behaviour warrants further investigation and diagnosis.

Deviance

Deviance refers to the extent to which a behaviour is considered unusual or uncommon within a given society. Clinicians assess whether the behaviour deviates sufficiently from social norms to be considered 'abnormal'. When a behaviour is sufficiently rare and divergent from what is typically expected, it may indicate the presence of a clinical disorder.

Dysfunction

Dysfunction examines whether the behaviour interferes substantially with the person's daily life and functioning. The clinician evaluates how the behaviour impacts different aspects of the individual's life, including work, relationships, self-care and general activities. The key consideration is the degree to which the problematic behaviour disrupts normal functioning.

Distress

Distress relates to the level of upset or discomfort the behaviour causes to the individual experiencing it. This dimension should be assessed independently from the other diagnostic criteria because an individual may be severely distressed by their circumstances yet still function adequately in other life domains.

The subjective experience of the patient is particularly important here, as they may be experiencing considerable difficulty even when this is not externally visible. Conversely, an individual may face substantial life challenges but report minimal distress, whilst another person may be deeply distressed by issues that others perceive as minor. This variability highlights the importance of considering the individual's personal experience.

Danger

Danger assesses the risk the behaviour poses, both to the individual themselves and to others around them. Clinicians must evaluate two key aspects: the potential for self-harm and the risk of harm to others. When an individual's behaviour places their own life or the lives of others in considerable jeopardy, this may indicate that intervention is necessary.

The severity of the danger can be conceptualised on a scale, as many people engage in behaviours that carry some degree of risk. However, when the behaviour is extremely hazardous and this risk is not being adequately addressed, a diagnosis may be warranted to facilitate appropriate intervention.

Evaluation of the four 'Ds' framework

Subjectivity and interpretation

The four dimensions framework faces several methodological challenges. A particularly serious concern is the potential for subjectivity in how clinicians interpret the patient's experience. Clinicians must consider how the individual is managing the behaviour under discussion, as what one person considers dysfunctional may be perceived quite differently by another. This introduces an element of subjective judgement into what should ideally be an objective diagnostic process.

Reliability concerns

Reliability is another important consideration. For the diagnostic decision to be reliable, the clinician must systematically explore all four dimensions with every patient, ensuring that everyone is assessed using a standardised approach. Additionally, any determination regarding the level of 'deviance' displayed by an individual must be based on standardised measures rather than subjective impressions.

Standardised assessment

Standardised tests exist to assess symptoms of many disorders, and these should be employed rather than relying solely on personal judgement about the patient's symptoms. However, an argument regarding the 'deviance' dimension is that certain problematic behaviours are not genuinely rare.

Issues of social control

The diagnostic process has broader social implications. Many critics argue that clinicians possess considerable power in diagnosing mental health difficulties, as there can be serious consequences for patients once they have been labelled as 'mentally ill'.

Practical considerations in clinical assessment

Clinical interviews

The diagnostic process is typically conducted through clinical interviews, which involve gathering important personal information about the individual regarding their health. These may be unstructured or semi-structured interviews. The reliability and validity of these interviews present several challenges:

• Self-report limitations: Patients may not always provide accurate information. They might be truthful, withhold information, or embellish their responses when providing self-report data to researchers or clinicians. This could substantially affect the validity of any diagnosis reached.

• Clinician focus: A clinical interview is guided by the clinician's questions. If they concentrate on one particular set of symptoms, their diagnosis may differ from that of a clinician who focuses on different symptoms.

• Variable conclusions: It is not simply the patient's responses that can lead to misdiagnosis; the structure and focus of the clinical interview itself can influence diagnostic outcomes.

Classification systems

Mental disorders are described as collections of symptoms by the medical profession, much like other illnesses. Two major classification systems are used internationally to standardise the diagnosis of mental health conditions.

Historical development

The foundations for modern classification systems were established in the late 19th century by Emil Kraepelin in his Compendium der Psychiatrie, first published in 1883. Kraepelin argued that psychiatric disorders were fundamentally physical in nature and should be studied as a branch of medical science. He believed that, like many medical disorders, it was possible to classify specific mental health disorders by their symptoms and therefore diagnose them and predict their course.

European doctors such as Eugen Bleuler (who introduced the term 'schizophrenia') further developed the system in the early 20th century.

The International Classification of Diseases (ICD)

The ICD is not solely concerned with mental health disorders but encompasses all diseases. ICD-10, published in 1948 by the World Health Organization, contains a specific section (F) for mental health disorders. The ICD is currently in its tenth version and is undergoing revision for release in 2017.

Structure and coding system

Within the mental health section, the ICD groups each disorder as part of a family. For example, mood (affective) disorders constitute the family that includes depression in all its forms, including bipolar disorder and any other mood disorder.

Using the ICD in practice

Clinicians can use the system to guide their diagnosis through a clinical interview with the patient. This requires expertise regarding the nature of mental disorders, as they are typically diagnosed based on behaviour rather than their presentation. However, the system does provide a foundation on which to base judgements, offering details of likely symptoms for each disorder and their severity and duration, which facilitates diagnosis.

In some instances, the diagnosis will be tentative or provisional, but sometimes a confident diagnosis can be made when the patient clearly presents with symptoms that match the description in the ICD manual.

The Diagnostic and Statistical Manual of Mental Disorders (DSM)

The DSM adopts a similar approach, grouping disorders into 'families' with linked disorders grouped together. This enables clinicians to move from a general diagnosis to a specific one, with guidance provided about the likely combination of symptoms and their severity.

DSM structure

The DSM V is organised into three main sections:

1. Section one: An introduction to the manual with instructions on its use.

2. Section two: The most important section, containing the classification of the main mental health disorders. This includes neurodevelopmental disorders, schizophrenia, bipolar disorders, depressive disorders, anxiety disorders and obsessive disorders.

3. Section three: Contains other assessment measures to aid diagnosis. This includes a cultural formulation interview guide to help diagnose individuals from different cultural backgrounds. It also includes other conditions being assessed for possible future diagnosis (for example, caffeine use disorder and Internet addiction disorder).

DSM IV-TR: The multiaxial system

DSM IV, originally published in 1994 and updated to DSM IV-TR in 2000, was described as a 'multiaxial tool' because of its five axes or chapters:

• Axis 1: Described the major clinical syndromes, or mental health disorders such as schizophrenia and anxiety disorders.
• Axis 2: Described the symptoms related to personality disorders.
• Axis 3: Described medical conditions, such as brain damage or HIV, that could be used to explain or mediate the onset of clinical issues.
• Axis 4: Described psychosocial and environmental problems that could be implicated in the onset or course of a mental health disorder (for example, bereavement, loss of housing or employment could trigger depression).
• Axis 5: Contained a scale to assess global functioning of an individual.

Clinicians could use this scale to assess how well an individual was able to perform normal activities such as washing, dressing and socialising. The functioning score given to an individual helped with diagnosis and was also used to assess the need for treatment and the type of treatment necessary.

DSM 5: Changes and updates

The latest version of the DSM reflects developmental and lifespan considerations, recognising that disorders thought to reflect developmental processes – such as neurodevelopmental disorders and those on the schizophrenia spectrum – tend to occur early in life, whilst those more commonly developed during adolescence, such as depression, appear later. This highlights the understanding that some psychiatric illnesses occur during particular periods in development.

Cultural considerations in diagnosis

DSM and cultural differences

There is not complete agreement between the European ICD and the American DSM, which means that diagnostic systems – even when used appropriately – might lead to different diagnoses. This challenges the notion that it is possible to have a universal diagnostic system.

The recent edition of DSM has also sought to make diagnosis more accurate for people from cultural backgrounds different from those traditionally represented. In previous DSM IV-TR versions, 'culture-bound' syndromes were presented in a separate chapter dealing with mental health disorders found in other cultures. However, the DSM V now takes a more integrative approach with greater cultural sensitivity. It is now recognised that symptoms manifest differently in different cultures.

Additionally, clinicians are now encouraged to consider the cultural background of the patient using the cultural formulation interview guide.

Individual and cultural variations

Race and culture are important issues in diagnosis. Behaviour that is common in one culture could be interpreted as symptomatic of a disorder in another, or if the patient belongs to a culture different from that of the clinician, they may be less likely to share their symptoms due to a sense of cultural shame. The boundary between what is considered normal and what is not varies across cultures for different types of behaviour.

Some cultures adopt more medicalised forms of diagnostic systems widely used, which overemphasise the separation of mind and body.

Culture-bound syndromes are disorders found in only one culture, such as ghost sickness, which occurs among people belonging to Native American tribes. The symptoms are recognised in the culture as indicating a specific disorder that is not recognised universally. Ghost sickness symptoms include an obsession with death, nightmares, loss of appetite, and feelings of suffocation and terror.

Reliability and validity of diagnostic systems

Mental health disorders do not have obvious measurable physiological signs, such as raised blood pressure or high temperature. Diagnosis therefore depends on the interpretation of behavioural symptoms, and this is not an exact science. There are always issues of reliability and validity that surround diagnosis. Classification systems, such as DSM and ICD, describe clusters of symptoms that define disorders and, if applied properly, should lead to higher-quality diagnoses. However, this does not mean they are universally accepted, and there are many influential critics of these systems.

Reliability and validity of diagnoses

Reliability of diagnosis

Reliability of diagnosis refers to the extent to which clinicians agree on the same diagnosis for the same patient. Diagnosis is complex, particularly as the same symptoms can occur across different disorders. Two clinicians might observe the same symptoms but assign their cause to different disorders. This would suggest that the diagnosis is unreliable.

Inter-rater reliability

For a system of diagnosis to be reliable, it needs to pass an inter-rater reliability test. Inter-rater reliability refers to the degree of agreement and consistency between raters about the thing being measured. This involves presenting two or more clinicians with the details of a person's case history and assessing the level of agreement between them. If all the clinicians (raters) agree on the same diagnosis, then the system of diagnosis can be said to have high inter-rater reliability.

Tests on early diagnostic systems showed typically low inter-rater reliability. For example, Beck (1954) found that the same set of symptoms were only diagnosed as the same disorder in approximately half of cases, suggesting low reliability. However, over the years as the systems have developed, further studies showed that reliability has improved.

Factors affecting reliability

Patient factors

Unreliable diagnosis may occur due to patient factors. Information provided by the patient to the clinician may be inaccurate due to problems with memory, denial or shame. These psychological factors, along with specific issues such as disorganised thoughts, psychopathy or manipulative tendencies, can make diagnosis difficult and likely to differ between clinicians.

Clinician factors

The unstructured nature of the clinical interview can lead some clinicians to focus on certain symptom presentations. For instance, some may focus on nightmares whilst others may follow a different course of questioning, such as exploring a traumatic past event. This can lead to different information being gathered about a patient and result in different diagnoses.

Clinicians also use their subjective judgement according to how they interpret the symptoms a patient presents. This is largely dependent on the background, training and experience of a clinician. For example, a clinician with psychodynamic training may emphasise the importance of early childhood experiences and mistake hallucinations for a past trauma, whilst a medically trained psychiatrist might explain hallucinations as a consequence of excess dopamine in the brain.

The introduction of tighter clinical interviews and diagnostic classification systems have improved the reliability of diagnosis and limited the subjective interpretation brought about by clinician judgement.

Validity of diagnosis

Even if a diagnosis can be said to be reliable, for it to be of any use the diagnosis must also be valid. It must genuinely reflect the underlying disorder, because the consequences of misdiagnosis can be very serious. Misdiagnosis leads to treatment at best that might delay recovery and at worst could make the person's condition much more severe. Clinicians can establish validity in a variety of ways.

Concurrent validity

Concurrent validity is a method of establishing validity that compares evidence from several studies testing the same thing to see if they agree. This could be checked by examining another diagnostic tool, such as comparing the DSM with the ICD. If there is broad agreement about which symptoms constitute which disorder, then broad concurrent validity can be established.

Aetiological validity

Aetiological validity can be established by examining what is known about the causes of the disorder and matching them to the person's history. Aetiological validity refers to the extent to which a disorder has the same cause or causes.

Predictive validity

Predictive validity should also be examined. Predictive validity refers to the extent to which results from a test such as DSM, or a study, can predict future behaviour. This is where the future course of the disorder is known and can be applied to the person, so the diagnosis can be checked against this outcome to see if it is valid.

Implicit biases in diagnosis

Issues that affect reliability and validity centre on the interpersonal exchange between client (or patient) and clinician in the diagnostic interview. The clinician may be affected by implicit biases in their interpretation of the information given to them. Implicit bias refers to a positive or negative mental attitude towards a person, thing or group that a person holds at an unconscious level.

According to Aboraya et al. (2006), these clinician variables include their training and perception of presenting symptoms, with more focus on the acute symptoms and perhaps overlooking other symptoms as a result. This is further exacerbated by patient variables, such as their current state during the diagnosis. Their mood, memory and levels of shame associated with their symptoms can all lead to inaccurate information being provided to the clinician.

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