One of the main reasons mental health professionals diagnose their patients is to enable good decisions about how to help them. For decades, mental health diagnoses have been based on the assumption that people fit neatly into diagnostic categories such as schizophrenia, depression, or alcohol dependence. However, research has shown that psychiatric patients do not fit neatly into diagnostic categories. The use of a diagnostic system that is not based on evidence has made it more difficult for mental health professionals to help their patients.
Instead of diagnostic categories, research supports an alternative system of mental disorder in which a network of psycho-social-biological dimensions are used to characterize patients. For example, one dimension is internalizing, or the general tendency to have experiences of anxiety, depression, and related problems. One premise of a dimensional system is that it is clinically important to know the level of internalizing problems in all patients, regardless of their specific diagnosis.
The Hierarchical Taxonomy of Psychopathology (HiTOP) consortium is a group of clinical researchers promoting the idea that diagnoses should be based on the best available evidence about how people are different from one another. HiTOP also refers to a specific evidence-based model for psychopathology diagnosis.
More research is needed on how to use the HiTOP system to guide treatment selection. So far, most psychotherapy research has been based on the traditional categorical system. Although this research has convincingly shown that psychotherapy is effective, psychotherapy research (with few exceptions) has not identified specific kinds of psychotherapy that are effective for specific diagnoses. This may be because of problems with those diagnoses. Research based on an evidence-based model such as HiTOP may be more effective for guiding clinical practice.
In an article in the Journal of Psychotherapy Integrationopens in new window, Christopher Hopwood and other members of the Hierarchical Taxonomy of Psychopathology attempt to address this gap in the research. The goal of the article was to generate a conceptual framework for guiding clinical practice and research designed to select psychotherapy interventions based on evidence-based diagnosis. The authors present practice and research principles for three kinds of psychological intervention. Common factors are practices that have been linked to better outcomes across different kinds of therapies, such as empathy and common goals. Cognitive-behavioral factors are strategies specific to that kind of psychotherapy, such as homework or exposure-based treatments. Finally, relational factors are strategies involving the therapeutic use of the relationship between therapist and client, commonly emphasized in psychodynamic therapies.
The authors demonstrate the use of these principles in the example of a young man with a range of symptoms, including panic attacks, anxiety, and gastrointestinal issues. This client met criteria for several different and unrelated diagnoses in the traditional categorical system, which provided little guidance about treatment. In contrast, his HiTOP diagnosis was more holistic and straightforward, and it led to a clearer strategy for intervention from either the cognitive–behavioral or relational perspectives.
Evidence-based models of psychopathology such as HiTOP could potentially revolutionize the field’s understanding of mental disorder. At a general level, HiTOP helps explain otherwise vexing issues like comorbidity and heterogeneity and connects diagnosis to models of individual differences that are more commonly used in basic science. It also provides a theoretically neutral language that can help to integrate ideas about treatment from different psychological traditions.
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