A Paradigm Shift With New Windows to Mental Health

Diagnosis is a critical step in clinical practice for mental health care providers. There are two main types of diagnostic systems: categorical and dimensional. Categorical approaches assume each condition is a separate and distinct category. Dimensional approaches, in contrast, view conditions along a dimension, continuum, or spectrum.

The Problem

For over a century, research on psychopathology has focused on categorical diagnoses – a legacy of the medical model of mental illness (psychiatry). As a result, the prevailing systems are categorical: namely, the Diagnostic and Statistical Manual of Mental Disorders (DSM) – developed by the American Psychiatric Association (APA); and the International Classification of Diseases (ICD) – developed by the World Health Organization (WHO). Such models have dominated academia, the mental health industry, and society at large. However, despite their benefits and popularity, categorical systems have very significant shortcomings.

Lack of Diagnostic Precision

Mental health problems are difficult to put into categories, as they lie on the continuum between pathology and normality – just like your body weight and blood pressure. This issue is particularly relevant when diagnosing personality disorders. Here are three examples:

1. There are 227 possible ways to meet the DSM criteria for major depressive disorder (MDD).
2. To diagnose borderline personality disorder (BPD), the DSM-5 system comprises nine diagnostic criteria, of which a minimum of five need to be present. Performing this algorithmic combination yields 256 distinct presentations of BPD.
3. Attempting to capture the range of symptoms for the diagnosis of post-traumatic stress disorder (PTSD), following the DSM-5, yields the phenomenal amount of 636,120 combinations.

Subjective, Reductionist, and Atheoretical

The DSM system is a codified system that uses a phenomenological approach based on the consensus of experts. This subjective, reductionist, and non-theoretical approach (lacking psychological theory) takes a biological perspective on the mind, thus, dismissing recent advances from neurobiological and sociocultural perspectives and their contributions to the science of the mind.

As a result, the DSM system poses problems to understanding the true nature and sources of psychopathology, including low symptom specificity, prevalent comorbidity (overlapping of categories), pronounced diagnostic variations, and poor reliability. Not surprisingly, “the biomedical model era has been characterized by a broad lack of clinical innovation and poor mental health outcomes” and a lack of clinical utility.

Pathologization of Normality and Lack of Cultural Sensitivity

Over-diagnosing and pathologizing normality are common in psychiatry and the DSM system. A controversial change incorporated in the DSM-5 revision relates to eliminating its “bereavement exclusion clause” by dismissing the fact that depressive symptoms can be normal during recent bereavement. This also exemplifies the social and cultural construction of depression and the DSM-5 system’s lack of cultural sensitivity. This illustrates more inherent flaws and clinical limitations of the DSM-5 classification method, which make its diagnostic validity highly questionable.

Self-stigma, Labelling, and Favoring the ‘Big Pharma’

Another set of criticisms of categorical systems is the “paradox of self-stigma,” noting the negative implications of public stigma and self-stigma, which results in decreased self-efficacy and self-esteem through believing the many stereotypes associated with mental illness. Allen Frances, former chair of the task force that produced the DSM-5, has been openly critical of the current DSM-5 by referring to it as “the bible of psychiatry; the go-to place to find out who is sick and who is not” and playing “into the hands of ‘Big Pharma,’ who are reaping multi-billion-dollar profits.”

According to Frances, the changes implemented on the DSM-5 did not affect psychiatric diagnoses, which still rely exclusively on fallible subjective judgments rather than objective testing, and psychiatric diagnosis is facing a renewed crisis of confidence caused by diagnostic inflation.

Similarly, other authors claim that psychiatric labels serve the interests of certain clinicians and their professional associations and the pharmaceutical industry. Some researchers talk about epistemic corruption and use the analogy of the DSM system attempting to standardize normality and mental disorders as evocative of the “McDonaldization” of economic and social life.

Not surprisingly, growing attention has been focused on the transparency and potential conflicts of interest of biomedical sciences and clinical medicine, along with recommendations of full disclosure by DSM panel members of their financial interests in the manufacture of drugs aimed at treating mental illness.

The Solution – The Hierarchical Taxonomy of Psychopathology (HiTOP)

The Hierarchical Taxonomy of Psychopathology (HiTOP) is a new dimensional classification system developed to address the limitations of traditional taxonomies (e.g., DSM-5) and reflects state-of-the-art scientific evidence. Research evidence (as opposed to ‘expert opinions’) indicates that multiple disorders are, in fact, “sequentially comorbid, recurrent/chronic, and exist on a continuum.”

Summary of HiTOP System Benefits

The HiTOP:

1. Proposes to view mental health within a spectrum. This allows for capturing the degrees of severity of mental health problems.
2. Simplifies the classification of mental illness, thus, allowing researchers and clinicians to focus on finer symptoms in detail or assess broader problems as necessary. For example, while the DSM-5 puts social anxiety disorder in one category, the HiTOP model describes it as a graded dimension, ranging from people who experience mild discomfort in a few social situations (e.g., public speaking) to those who are extremely anxious in most situations.
3. Effectively summarizes information on shared genetic vulnerabilities, environmental risk factors, and neurobiological abnormalities.
4. Allows the narrow level of hierarchy to provide good targets for symptom-specific treatments. In contrast, the higher level of the hierarchy is helpful when designing comprehensive treatment packages and developing public health policy.
5. Adheres to the most up-to-date scientific evidence rather than relying on expert opinion (like the DSM-5 system).

Conclusion

For over a century, mental health has been dominated by categorical diagnoses. The DSM system has been considered the most important document for diagnosing and classifying mental disorders. Growing research evidence strongly indicates that symptoms of psychological distress are most accurately represented by using dimensional measures rather than discrete units.

This indicates the superiority of dimensional approaches to the science of mental illness. The new HiTOP is a dimensional system that has the potential to accelerate and improve research on mental health problems, as well as efforts to more effectively assess, prevent, and treat mental illness.