ear Colleagues,Phenotypes
can be considered as the clinical expression of a given situation, which,in the cases discussed here, may have a pathological
or nonpathological character.Thesephenotypic
expressions have, above all, a qualitative dimension, like that
found in thevarious systems for nosological
classification.Endophenotypes, on
the other hand, can be traced to the genome, but may also beunrelated to a heritable transmission and result from
events during prenatal or perina-tal life. Moreover, these
cannot be linked to specific psychiatric disorders and are moreoften the expression of biological perturbations. Endophenotypes
can be expressed indifferent manners, for
example, abnormalities in cognition, electrophysiology and corti-cal evoked potentials, cerebral imaging, neurochemistry, neuropsychopharmacology, andassociated clinical disorders. Endophenotypes do, however, have
one feature in common:the advantage of
being quantifiable. No doubt we could speak of the endophenotypicspectrum of a disorder, which
clearly demonstrates the value of a wide
variety ofapproaches in the
field of the diagnosis and follow-up of psychiatric disorders.Thanks
to its Coordinating Editor, Prof David Rubinow, this issue of Dialogues
inClinical Neuroscience has
provided us with an excellent opportunity to gather articles onthis subject from undisputed leaders in the field, thereby
creating a solid overview.Yours sincerely,Jean-Paul Macher, MDMarc-Antoine
Crocq, MDE
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