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Online Discussions

Updated 14 April 2006
Printable version

Live Discussion: New Findings in Psychosis: Breaking Down Diagnostic Barriers

Nick Craddock

Mike Owen

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Like many other researchers and clinicians, Nick Craddock and Mike Owen of Cardiff University in Wales feel that the traditional boundaries of psychotic and mood disorders may be getting in the way of progress in basic research, particularly genetics. In the past year, they have published a series of papers, both theoretical and experimental, that argue for moving beyond the Kraepelinian dichotomy of schizophrenia and bipolar disorder as distinct disease entities.

On May 15, 2006, Craddock and Owen led us through a live online discussion of these issues, with an eye toward finding alternative approaches to diagnosis and classification. Mayada Akil of the National Institute of Mental Health served as moderator. Please read the edited transcript, two recent review papers (full text can be accessed by clicking on the journal images above), and the text below and continue this discussion by offering comments.

View Transcript of Live Discussion — Posted 27 June 2006

View Comments By:
Gunvant Thaker — Posted 24 April 2006
William Carpenter — Posted 28 April 2006
Avi Peled — Posted 7 May 2006
Mario Maj — Posted 8 May 2006
Patricia Estani — Posted 10 May 2006
Ian Brockington — Posted 12 May 2006
Avi Peled — Posted 13 May 2006
Assen Jablensky — Posted 13 May 2006
Robin Murray — Posted 14 May 2006
Avi Peled — Posted 15 May 2006
Wayne Fenton — Posted 15 May 2006
Carol Tamminga — Posted 15 May 2006
Herbert Meltzer — Posted 15 May 2006
Francis A O'Neill — Posted 24 May 2006
Karl-Ludvig Reichelt — Posted 29 May 2006
Kiumars Lalezarzadeh — Posted 18 June 2006


by Nick Craddock and Mike Owen

It has been conventional for psychiatric research, including the search for predisposing genes, to proceed under the assumption that schizophrenia and bipolar disorder are separate disease entities with different underlying etiologies. These represent Emil Kraepelin's traditional dichotomous classification of the so-called "functional" psychoses and form the basis of modern diagnostic practice. However, findings emerging from many fields of psychiatric research do not fit well with this model. In particular, the pattern of findings emerging from genetic studies shows increasing evidence for an overlap in genetic susceptibility across the traditional classification categories, including association findings at DAOA(G72), DTNBP1 (dysbindin), COMT, BDNF, DISC1, and NRG1. The emerging evidence suggests the possibility of relatively specific relationships between genotype and psychopathology. For example, DISC1 and NRG1 may confer susceptibility to a form of illness with mixed features of schizophrenia and mania. The elucidation of genotype-phenotype relationships is at an early stage, but current findings highlight the need to consider alternative approaches to classification and conceptualization for psychiatric research rather than continue to rely heavily on the traditional Kraepelinian dichotomy.

The aim of this Schizophrenia Research Forum discussion is to discuss the current utility, or otherwise, of the Kraepelinian dichotomy for research and clinical practice and consider this against alternative approaches to diagnosis and classification. To focus discussion, two specific issues will be addressed, in the form of questions:

1) Do the disadvantages of the Kraepelinian dichotomy now outweigh the advantages?

2) What are the best alternative approaches to diagnosis and classification? (e.g., dimensions, alternative categories, prototypes.…)

Craddock N, O'Donovan MC, Owen MJ. Genes for schizophrenia and bipolar disorder? Implications for psychiatric nosology. Schizophr Bull. 2006 Jan;32(1):9-16. Abstract

Craddock N, Owen MJ. The beginning of the end for the Kraepelinian dichotomy. Br J Psychiatry. 2005 May;186:364-6. Abstract

Comments on Online Discussion
Comment by:  Gunvant Thaker
Submitted 23 April 2006 Posted 24 April 2006

Nick Craddock and Michael Owen in their editorial in the...  Read more

View all comments by Gunvant Thaker

Comment by:  William Carpenter, SRF Advisor (Disclosure)
Submitted 27 April 2006 Posted 28 April 2006

Very important topic coming at a good time. Over the next...  Read more

View all comments by William Carpenter

Comment by:  Avi Peled
Submitted 5 May 2006 Posted 7 May 2006

Allen Frances, the chairperson of the task force that...  Read more

View all comments by Avi Peled

Comment by:  Mario Maj
Submitted 8 May 2006 Posted 8 May 2006

I think that what we call "schizophrenia" and "bipolar...  Read more

View all comments by Mario Maj

Comment by:  Patricia Estani
Submitted 10 May 2006 Posted 10 May 2006

I would like to express my general agreement with the...  Read more

View all comments by Patricia Estani

Comment by:  Ian Brockington
Submitted 12 May 2006 Posted 12 May 2006

In my editorial in the journal European Psychiatry (1992,...  Read more

View all comments by Ian Brockington

Comment by:  Avi Peled
Submitted 13 May 2006 Posted 13 May 2006

I agree with Ian Brockington that schizophrenia is...  Read more

View all comments by Avi Peled

Comment by:  Assen Jablensky
Submitted 13 May 2006 Posted 13 May 2006

Despite an ever increasing volume of research data, the...  Read more

View all comments by Assen Jablensky

Comment by:  Robin Murray, SRF Advisor
Submitted 14 May 2006 Posted 14 May 2006

I largely agree with the argument put forward by Craddock...  Read more

View all comments by Robin Murray

Comment by:  Avi Peled
Submitted 15 May 2006 Posted 15 May 2006

As Assen knows, I agree and support the idea that the...  Read more

View all comments by Avi Peled

Comment by:  Wayne Fenton
Submitted 14 May 2006 Posted 15 May 2006

I believe findings of shared genetic determinants across...  Read more

View all comments by Wayne Fenton

Comment by:  Carol Tamminga, SRF Advisor
Submitted 15 May 2006 Posted 15 May 2006

The interesting position by Craddock and Owen is one that...  Read more

View all comments by Carol Tamminga

Comment by:  Herbert Meltzer (Disclosure)
Submitted 15 May 2006 Posted 15 May 2006

A Concept Foretold—Kraepelin vs. Greisinger

As a...  Read more

View all comments by Herbert Meltzer

Comment by:  Francis A O'Neill
Submitted 24 May 2006 Posted 24 May 2006

There is no doubt that the current classification system...  Read more

View all comments by Francis A O'Neill

Comment by:  Karl-Ludvig Reichelt (Disclosure)
Submitted 29 May 2006 Posted 29 May 2006

There will never be an end to this discussion as long as...  Read more

View all comments by Karl-Ludvig Reichelt

Comment by:  Kiumars Lalezarzadeh
Submitted 9 June 2006 Posted 18 June 2006

High prevalence of schizophrenia in cities with high...  Read more

View all comments by Kiumars Lalezarzadeh
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