Understanding the Challenges of the Current Diagnostic System

Successfully treating a mental health disorder begins with an accurate mental health diagnosis. Yet, recent estimates have found that most people will experience a “meaningful diagnostic error” at least once in their lives. A diagnostic error can be defined as the failure to accurately establish and explain a mental health problem or a failure to communicate the diagnosis to the patient. In the US alone, postmortem examination research has found that diagnostic errors could account for 10% of paid medical malpractice deaths.^[1]

With 1 in 5 US adults affected by mental illness each year, it is clear that accurately diagnosing problems with mental health disorders is imperative.^[2] The current diagnostic system, while periodically updated, faces numerous challenges in this task. This article explores some of the key problems with mental health diagnosis under the current diagnostic system and the proposed alternatives.

What Are the Limitations of Categorical Mental Health Diagnoses?

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) is considered the current gold standard for categorical mental health diagnosis. The DSM-5 was first published in 2013 and is updated periodically to provide accurate diagnostic criteria for clinicians. This lengthy manual covers a vast array of mental health conditions and lists the symptoms required for diagnosis.

Unfortunately, the DSM-5 and similar diagnostic tools, such as the International Classification of Diseases (ICD), are limited by an inability to:

• Judge the ‘big picture’ and consider the source of information used for diagnosis. For youth, in particular, there may be discrepancies between the parents and the patient in terms of perspective on mental health needs and symptoms.
• Consider the time frame for symptoms. Among medical professionals, there are some discrepancies about how long symptoms should be present before making a diagnosis.
• Define normal behavior appropriately. While the DSM-5 and ICD may aim to identify patients who are suffering or are outside the norm, they may set too narrow a definition. Furthermore, these methods can rely too heavily on a statistical definition of normal, misleading clinicians to diagnose patients outside the average but not necessarily ‘abnormal.’
• Account for situational factors. Mental health symptoms may meet diagnostic criteria only in certain situations. The current methods do not look for cross-situational consistency before determining a diagnosis.
• Place more emphasis on data. While determining symptoms as markers of disorders is key, diagnostic methods don’t place enough emphasis on using hard data to predict outcomes and drive decisions.
• Adjust for changing criteria. As criteria change, more diagnoses may be made – potentially to the point that diagnostics become inaccurate or patients are overdiagnosed.^[3]

How Reliable Are Mental Health Diagnoses?

With clear limitations, the reliability and validity of current diagnostic criteria must be carefully considered. There are two main points to consider in terms of diagnostic reliability:

• Patients are inconsistent with how they express and report the symptoms that are required to make a diagnosis.
• Clinicians are inconsistent in applying those criteria to make a diagnosis.

Furthermore, as the American Journal of Psychiatry notes, “It is unrealistic to expect that the quality of psychiatric diagnoses can be much greater than that of diagnoses in other areas of medicine, where diagnoses are largely based on evidence that can be directly observed.”^[4]

This begs the question: how reliable can a mental health diagnosis be when much of the diagnosis criteria is based on patient-reported symptoms and professional opinion? This is what updates to the DSM-5 have intended to resolve. By developing highly specific lists of symptoms, clinicians should, in theory, reduce overdiagnosis and misdiagnosis. Unfortunately, this does not solve the core issue of reliability – it is an overarching issue with the current diagnostic system as a whole rather than a quirk of the current DSM edition.

The Challenges of Comorbidity

In addition to the challenges posed by unreliability in patient-reported symptoms and clinician-determined diagnoses, comorbidity further complicates the matter. The co-occurrence of two medical conditions has been long documented in many fields, but it is a relatively new concept in the field of mental health. Acknowledgment of overlapping symptoms and comorbid conditions in psychiatry is becoming more widespread in clinical practice and psychiatric research.

The problem is that comorbidity was initially defined as distinct additional clinical entities. In psychiatry, mental health conditions are rarely so distinct – the symptoms of one mental health disorder can be very similar or even identical to those of another. Few symptoms are specific to a sole mental health issue.

This poses a problem for the current diagnostic system, which seeks to firmly categorize mental health conditions with strict lists of diagnostic criteria. In fact, the system may be promoting artificial comorbidity by encouraging clinicians to strictly adhere to diagnostic criteria, leading to symptoms that don’t fit a certain condition being assigned to another. The more the current diagnostic system is refined with strict categorization, the more clinicians are prevented from viewing criteria as simply the minimum requirements for diagnosis. The fallout of this could be an increase in overdiagnosis.^[5]

The Problem of Overdiagnosis

Overdiagnosis is broadly defined as turning healthy individuals into patients unnecessarily. In the mental health field, this is typically due to over-detection (identifying symptoms that, although may be abnormal, are not malignant) or over-definition (changing criteria to lower thresholds and include patients with milder symptoms).

Patients with benign symptoms or very mild symptoms are put at risk through overdiagnosis in the current diagnostic system. They are exposed to medications and lifestyle changes that may, in fact, be detrimental to their wellbeing. The effects of overdiagnosis can be physical, psychological, social, and financial.^[6]

Furthermore, medicalizing normal human experiences is a dangerous side effect of the current diagnostic system that places so much emphasis on strictly categorizing conditions. As Dr. McElveen, Department of Psychiatry, Stobhill Hospital, Glasgow, noted in a letter published in the British Journal of General Practice:

“I am increasingly seeing colleagues in both disciplines labeling normal life experiences as mental illness. They then appear to peddle the hope that a tablet (often an antidepressant) will sort out the patient’s alcoholic husband and noisy neighbours.”^[7]

What Is Diagnostic Inflation?

Overdiagnosis could be considered a symptom of a wider issue with the current diagnostic system. With expanding diagnostic categories and lowering diagnostic thresholds, ‘diagnostic inflation’ is emerging as one of the key problems with mental health diagnosis.

The fifth edition of the DSM was produced, in part, to control diagnostic inflation – an increase in both the number of psychiatric conditions and the number of patients diagnosed – by more strictly categorizing conditions. However, critics of the DSM-5 suggest that it has had the opposite effect, making it easier for patients to find a diagnosis for normal life experiences.^[8]

Bereavement is a clear example of one of the current issues in mental health diagnostics. In past editions of the DSM, bereavement was an exclusion criterion for major depressive disorder, indicating to clinicians that the mental health struggles experienced during periods of grief are a normal and expected part of life. The current diagnostic system does not exclude bereavement, suggesting that clinicians may be able to diagnose a patient with a mental health condition based on the ‘symptoms’ experienced after the loss of a loved one.

Are There Any Alternatives to the Current Diagnostic System?

To summarize, the current diagnostic system relies heavily on categorization to create stricter diagnostic criteria for clinicians in an attempt to reduce diagnostic inflation and improve reliability. However, the challenges of mental health diagnostics remain prevalent:

• The system limits the source of information, time frame, and situational factors that can be considered for a diagnosis.
• Changing diagnostic criteria and definitions of normality complicate the diagnostic process.
• Relying on patient-reported symptoms and clinician perspectives calls diagnostic reliability into question.
• Overdiagnosis is leading to healthy individuals being unnecessarily diagnosed and normal life experiences being an unnecessary cause for medication.

To resolve these problems, alternatives that won’t just update the current diagnostic system but fully replace it have been proposed. These alternatives may even reframe how the mental health field interprets unusual or extreme thoughts, feelings, and actions – seeing them as normal or adaptive responses to adversity.^[9]

Another proposed alternative would seek to use zebrafish – a species with genetic similarities to humans – to understand the genetic and biological roots of mental health disorders. As genetic factors are thought to play a large role in many psychiatric disorders, using cell and animal studies may enable researchers to understand how gene variants and drugs work in the human body.^[10]

To conclude, it must be emphasized that while the current diagnostic system is not without serious challenges, it is still a valuable resource for mental health professionals. The stigma surrounding mental health and lack of mental healthcare resources affect millions of people worldwide – for up to 70% of the world’s population, there is access to less than one psychiatrist per 100,000 people.^[11] For many of these people, the current diagnostic system could be the key to finding answers and accessing treatment until a more effective system is established.