Skip to main content Accessibility help

What kinds of things are psychiatric disorders?

  • K. S. Kendler (a1), P. Zachar (a2) and C. Craver (a3)

This essay explores four answers to the question ‘What kinds of things are psychiatric disorders?’ Essentialist kinds are classes whose members share an essence from which their defining features arise. Although elegant and appropriate for some physical (e.g. atomic elements) and medical (e.g. Mendelian disorders) phenomena, this model is inappropriate for psychiatric disorders, which are multi-factorial and ‘fuzzy’. Socially constructed kinds are classes whose members are defined by the cultural context in which they arise. This model excludes the importance of shared physiological mechanisms by which the same disorder could be identified across different cultures. Advocates of practical kinds put off metaphysical questions about ‘reality’ and focus on defining classes that are useful. Practical kinds models for psychiatric disorders, implicit in the DSM nosologies, do not require that diagnoses be grounded in shared causal processes. If psychiatry seeks to tie disorders to etiology and underlying mechanisms, a model first proposed for biological species, mechanistic property cluster (MPC) kinds, can provide a useful framework. MPC kinds are defined not in terms of essences but in terms of complex, mutually reinforcing networks of causal mechanisms. We argue that psychiatric disorders are objectively grounded features of the causal structure of the mind/brain. MPC kinds are fuzzy sets defined by mechanisms at multiple levels that act and interact to produce the key features of the kind. Like species, psychiatric disorders are populations with central paradigmatic and more marginal members. The MPC view is the best current answer to ‘What kinds of things are psychiatric disorders?’

Corresponding author
*Address for correspondence: K. S. Kendler, M.D., Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University Medical School, PO Box 980126, Richmond, VA 23298-0126, USA. (Email:
Hide All
Beck, AT, Alford, BA (2008). Depression: Causes and Treatment, 2nd edn. University of Pennsylvania Press: Philadelphia, PA.
Borsboom, D (2008). Psychometric perspectives on diagnostic systems. Journal of Clinical Psychology 64, 10891108.
Boyd, R (1991). Realism, antifoundationalism and the enthusiasm for natural kinds. Philosophical Studies 61, 127148.
Boyd, R (1999). Homeostasis, species, and higher taxa. In Species: New Interdisciplinary Essays (ed. Wilson, R. A.), pp. 141185. A Bradford Book/MIT Press: Cambridge, MA.
Carter, KC (2003). The Rise of Causal Concepts of Disease: Case Histories. Ashgate Publishing Company: Burlington, VT.
Cooper, R (2005). Classifying Madness. Springer: Dordrecht, The Netherlands.
Craver, CF (2007). Explaining the Brain. Clarendon Press: Oxford.
Dewey, J (1925). Experience and Nature (1925/1958). Dover: New York, NY.
Evans, AS (1993). Causation and Disease: A Chronological Journey. Plenum Publishing Corporation/Plenum Medical Book Company: New York, NY.
Fine, A (1984). The natural ontological attitude. In Scientific Realism (ed. Leplin, J.), pp. 83107. University of California Press: Berkeley, CA.
Haack, S (2003). Defending Science – Within Reason: Between Scientism and Cynicism. Prometheus Books: Amherst, NY.
International Schizophrenia Consortium (2009). Common polygenic variation contributes to risk of schizophrenia and bipolar disorder. Nature 460, 748752.
Jablensky, A, Sartorius, N, Ernberg, G, Anker, M, Korten, A, Cooper, JE, Day, R, Bertelsen, A (1992). Schizophrenia: manifestations, incidence and course in different cultures. A World Health Organization ten-country study. Psychological Medicine Monograph Supplement 20, 197.
James, W (1907). Pragmatism and the Meaning of Truth (1907, 1909/1975). Harvard University Press: Cambridge, MA.
Kendler, KS (1983). Overview: a current perspective on twin studies of schizophrenia. American Journal of Psychiatry 140, 14131425.
Kendler, KS (2005). ‘A gene for …’: the nature of gene action in psychiatric disorders. American Journal of Psychiatry 162, 12431252.
Kendler, KS (2008). Explanatory models for psychiatric illness. American Journal of Psychiatry 165, 695702.
Kendler, KS (2009). An historical framework for psychiatric nosology. Psychological Medicine 39, 19351941.
Kendler, KS, Baker, JH (2007). Genetic influences on measures of the environment: a systematic review. Psychological Medicine 37, 615626.
Kendler, KS, Gatz, M, Gardner, C, Pedersen, N (2006). A Swedish national twin study of lifetime major depression. American Journal of Psychiatry 163, 109114.
Koob, G, Kreek, MJ (2007). Stress, dysregulation of drug reward pathways, and the transition to drug dependence. American Journal of Psychiatry 164, 11491159.
Koob, GF (2009). Neurobiological substrates for the dark side of compulsivity in addiction. Neuropharmacology 56 (Suppl. 1), 1831.
Meehl, PE (1986). Diagnostic taxa as open concepts: metatheoretical and statistical questions about reliability and construct validity in the grand strategy of nosological revision. In Contemporary Directions in Psychopathology (ed. Millon, T. and Klerman, G.), pp. 215231. Guilford Press: New York, NY.
Murphy, D (2006). Psychiatry in the Scientific Image (Philosophical Psychopathology). MIT Press: Cambridge, MA.
Russo, SJ, Mazei-Robison, MS, Ables, JL, Nestler, EJ (2009). Neurotrophic factors and structural plasticity in addiction. Neuropharmacology 56 (Suppl. 1), 7382.
Sass, H (2007). The German Anthology of Psychiatric Texts. World Psychiatric Association: Chene-Bourg, Switzerland.
Schaffner, KF (1993). Discovery and Explanation in Biology and Medicine. The University of Chicago Press: Chicago, IL.
Shi, J, Levinson, DF, Duan, J, Sanders, AR, Zheng, Y, Pe'er, I, Dudbridge, F, Holmans, PA, Whittemore, AS, Mowry, BJ, Olincy, A, Amin, F, Cloninger, CR, Silverman, JM, Buccola, NG, Byerley, WF, Black, DW, Crowe, RR, Oksenberg, JR, Mirel, DB, Kendler, KS, Freedman, R, Gejman, PV (2009). Common variants on chromosome 6p22.1 are associated with schizophrenia. Nature 460, 753757.
Sullivan, PF, Neale, MC, Kendler, KS (2000). Genetic epidemiology of major depression: review and meta-analysis. American Journal of Psychiatry 157, 15521562.
Van Fraassen, BC (1976). To save the phenomena. Journal of Philosophy 73, 623632.
Wilson, RA, Barker, MJ, Brigandt, I (2007). When traditional essentialism fails: biological natural kinds. Philosophical Topics 35, 189215.
Woodward, J (2003). Making Things Happen. Oxford University Press: New York.
Zachar, P (2000). Folk taxonomies should not have essences either. Philosophy, Psychology and Psychiatry 7, 191194.
Zachar, P (2003). The practical kinds model as a pragmatist theory of classification. Philosophy, Psychology and Psychiatry 9, 219227.
Zachar, P (2008). Real kinds, but no true taxonomy: an essay in psychiatric systematics. In Philosophical Issues in Psychiatry: Explanation, Phenomenology and Nosology (ed. Kendler, K. S. and Parnas, J.), pp. 327355. Johns Hopkins University Press: Baltimore, MD.
Zachar, P, Kendler, KS (2007). Psychiatric disorders: a conceptual taxonomy. American Journal of Psychiatry 164, 557565.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Psychological Medicine
  • ISSN: 0033-2917
  • EISSN: 1469-8978
  • URL: /core/journals/psychological-medicine
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed