For example, research conducted as part of the RDoC initiative might not look at the symptom or surface level differences between different anxiety disorders defined by the DSM. Instead, studies might look at a certain symptom typically associated with anxiety disorders, such as fear, and study the neurobiological mechanisms, and endophenotypes, underlying fear so that we can better understand how or why a person might develop this specific symptom (see Figure 1.2).
The Hierarchical Taxonomy of The Psychopathology (Hitop) System
Building on the Achenbach system of classification, the HiTOP system (Kotov et al., 2017; Krueger et al., 2018) was developed to address limitations of categorical systems. HiTOP derived its psychopathology syndromes or disorders using statistical analyses, and is therefore a quantitative, “bottom up” approach to psychopathology. Behaviors and symptoms that mental health professionals typically assess were analyzed to identify which covaried, co‐occurred, or clustered together to form syndromes. The “H” in HiTOP (hierarchical) indicates that this system of classification is based on a hierarchical statistical model. After syndromes were statistically identified, they were then organized under higher‐order factors that describe the similarities of the disorders in that factor. For example, HiTOP lists the disorders major depressive disorder (MDD), dysthymia, general anxiety disorder (GAD), post‐traumatic stress disorder (PTSD), and borderline personality disorder (BPD) under a higher‐order “distress” factor based on statistical findings that the symptoms of all of these disorders covary. In all, there are currently seven higher‐order factors in the HiTOP system. These factors were then organized under spectra, or groups of factors that correlate with each other. For example, the substance abuse and antisocial behavior factors correlate, and this correlation is explained by an underlying disinhibited externalizing spectra (dimension), suggesting that both substance use problems and antisocial behaviors are both characterized by problems with self‐control of behaviors. Importantly, the HiTOP system is a dimensional classification system for psychopathology (Krueger et al., 2018).
FIGURE 1.2 Illustration of How the Research Domain Criteria (RDoC) Matrix Guides Research
The Limitations of Traditional Approaches to Diagnosis and Classification
Most of this chapter has been dedicated to reviewing major approaches to classifying and diagnosing psychopathology. At the beginning of this chapter, we noted that these systems are not perfect. The table in Figure 1.3 compares the limitations of each approach.
FIGURE 1.3 Limitations of Approaches to Diagnosis and Classification of Psychopathology
The Value of a Developmental Psychopathology Approach
We hope it is now evident that the major approaches to classification and diagnosis across history serve important purposes but also suffer from substantial weaknesses. In the next chapter, we will describe the developmental psychopathology approach to conceptualizing psychopathology. Developmental psychopathology (DP) means exactly what its name suggests: it is the study of psychological or mental disorders (psychopathology) from a developmental or lifespan perspective. Many features of the DP approach make it a superior alternative to understanding mental illness, particularly in children and adolescents. Briefly, it heavily emphasizes understanding normal development in order to better understand abnormal functioning, making it a dimensional approach to understanding psychopathology. It is also not a classification or diagnostic system per se. Therefore, similar to RDoC, it is not constrained by diagnostic labels or categories but can be used to study these constructs if desired. Also, like the RDoC initiative, and unlike statistical models of psychopathology like HiTOP, a DP approach to studying mental illness examines mechanisms underlying symptomology, rather than the phenotype alone. Finally, unlike all the models and approaches previously described, the DP approach emphasizes and systematically investigates developmental, individual, and environmental risk and protective factors in the etiology of all mental illness. This is particularly critical to understanding childhood and adolescent psychopathology.
Chapter Summary
This introductory chapter was meant to provide you with an understanding of traditional approaches to diagnosing and classifying psychopathology. We reviewed five diagnostic or classification systems and the limitations of these approaches. Finally, we gave you a preview of how a developmental psychopathology approach to conceptualizing psychopathology in children and adolescents can address the limitations of previous diagnostic systems.
Further Reading
1 Clark, L. A., Cuthbert, B., Lewis‐Fernández, R., Narrow, W. E., & Reed, G. M. (2017). Three approaches to understanding and classifying mental disorder: ICD‐11, DSM‐5, and the National Institute of Mental Health’s Research Domain Criteria (RDoC). Psychological Science in the Public Interest, 18(2), 72–145. doi: 10.1177/1529100617727266.
2 Insel, T., Cuthbert, B., Garvey, M., Heinssen, R., Pine, D. S., Quinn, K., Sanislow, C., & Wang, P. (2010). Research domain criteria (RDoC): Toward a new classification framework for research on mental disorders. Available at: https://pubmed.ncbi.nlm.nih.gov/20595427/.
3 Kotov, R., Krueger, R. F., Watson, D., Achenbach, T. M., Althoff, R. R., Bagby, R. M., & Eaton, N. R. (2017). The Hierarchical Taxonomy of Psychopathology (HiTOP): A dimensional alternative to traditional nosologies. Journal of Abnormal Psychology, 126(4), 454.
4 Regier, D. A., Kuhl, E. A., & Kupfer, D. J. (2013). The DSM‐5: Classification and criteria changes. World Psychiatry, 12(2), 92–98.
Discussion/Essay Questions
1 Discuss at least three purposes of classification and diagnostic systems for psychopathology.
2 Compare and contrast the categorical approach to classifying psychopathology of the DSM‐5 with at least one of the dimensional approaches to classifying psychopathology. Make a list of advantages and disadvantages for each approach.
3 Are dimensional approaches to thinking about psychopathology superior to categorical approaches? Provide evidence for your answer.
Glossary
Abnormal, in the context of psychopathology, can be defined as behaviors, emotions, and cognitions that deviate from the norm (culturally or developmentally) and cause distress, impairment in functioning, or endanger an individual or those around them.
Alternative Model for Personality Disorders (AMPD) is a hybrid (categorical and dimensional) model for diagnosing personality disorders found in Section III of the DSM‐5.
Categorical refers to an approach to classification of psychopathology that distinguishes between different forms of psychopathology by grouping symptoms to create distinct categories of diagnoses.
Classification is the act of categorizing things according to a set of criteria.
Continuum