By Elizabeth Ryznar, MD, MSc
Assistant Professor
Department of Psychiatry and Behavioral Sciences
Johns Hopkins School of Medicine
Our current culture exhorts us to “put the past behind us and face the future.” This is problematic though, because we do not know what the future holds, but we do very clearly know what came before. And as psychiatrists, we all know that ignoring the past can cause problems for individuals in the present and the future. In my talk, I drew on two historical examples to illuminate current challenges for our field, and offered strategies to better navigate the future in light of our history.
The first part of the talk outlined the history of the Diagnostic and Statistical Manual (DSM). References for the historical account are provided below. The takeaway points from this historical account of the DSM were as follows:
- First, classification schemes are created according to specific needs of the field or society.
- Second, each diagnostic system is constrained by its assumptions: the DSM adopts a very categorical approach to diagnosis—you either meet the criteria or you don’t; however, is mental illness so binary?
- Third, diagnostic labels unfortunately often do not accurately capture human pathology or suffering, as exemplified by the high rates of co-morbidity among DSM diagnoses. We need to ensure that we start thinking about our diagnoses as dogmatic, and that we think rigorously about need labels, like “treatment resistant depression”, which is not a meaningful construct.
One strategy that can help us is to maintain “conceptual humility.” Coined by Awais Aftab and Scott Waterman, conceptual humility is the “realization that [conceptual issues in psychiatry] are highly complex and despite our best efforts, often remain unsettled, that we are always operating within a philosophical framework, and that all philosophical frameworks have their limitations.”
The second part of the talk discussed the history of neurochemistry and the dopamine hypothesis in schizophrenia. References for the historical account are provided below. The takeaways from this history are that sometimes prevailing scientific opinion can be wrong and can take several decades to self-correct.
Part of the reason why prevailing scientific opinion can be wrong is that sometimes it is not within the realm of possibility to know something until we develop new technology. Furthermore, we should not get carried away with a single theory or a single cure for major psychiatric diagnoses. The dopamine hypothesis was based on a line of research using the amphetamine model of psychosis, which mimicked only the positive symptoms of schizophrenia, and the original hypothesis (claiming dopamine excess as cause of schizophrenia) was never supported by further research and had to be continuously amended. Nonetheless, the dopamine hypothesis dominated psychiatric research and practice, often to the detriment of other lines of research.
As we navigate the future, we must remember that there may be new technologies that may help us understand the brain in a different light. Moreover, one method of avoiding the pitfalls of the dopamine hypothesis is to adopt “explanatory pluralism”. Coined by Kenneth Kendler, explanatory pluralism is a philosophical approach to psychiatry that recognizes that, when it comes to pathophysiology, “what we can best hope for is lots of small explanations, from a variety of explanatory perspectives, each addressing part of the complex etiological processes leading to disorders. It will be particularly challenging to understand how these many different small explanations all fit together.”
Recommended Readings/References
- Aftab & Ryznar (2021). Conceptual and historical evolution of psychiatric nosology. Int Rev Psychiatry 33(5):486-499.
- Ryznar et al editors (2020). Landmark Papers in Psychiatry. Oxford University Press: Oxford, UK.
- Aftab & Waterman (2020). Conceptual competence in psychiatry: recommendations for education & training. Acad Psychiatry 45(2): 203-209.
- Baumeister & Francis. Historical development of the dopamine hypothesis of schizophrenia. J Hist Neurosciences 2002; 11(3): 265.
- Kendler (2005). Toward a Philosophical Structure for Psychiatry. Am J Psychiatry 2005; 162: 433–440
