[Schedule for evaluation of the deficit syndrome in schizophrenia: Schedule for Deficit Syndrome (SDS) (Kirkpatrick et al.). Importance pertinence of the SDS. Introduction of the French version].

The negative symptoms of schizophrenia have generated a great interest leading some authors (Crow, Andreasen, Kay) to delineate schizophrenic subtypes based on their presence or absence. Carpenter et al. have recently proposed another subtype, the deficit syndrome, based on Kraepelin's clinical description. This differs from other proposed negative subtypes and refers to the presence or absence of prominent, enduring and primary negative symptoms. Primary negative symptoms have to be due to psychophrenia itself, in other words, independent of factors such as depression, anxiety, akinesia... Kirkpatrick et al. have proposed the Schedule for the Deficit Syndrome (SDS) to reliably identify this deficit syndrome. Some studies using this instrument have supported the validity of the deficit syndrome concept. Particularly, deficit patients have clinical, neuropsychological, neurological, eye-tracking and brain imaging impairments compared to nondeficit patients. We realized a french translation of SDS and used it to study a biological index (plasma homovanillic acid, pHVA) among deficit and nondeficit schizophrenic patients. Our data suggest a specific biochemical basis for the deficit syndrome, ie, significant lower mean pHVA levels with a lack of diurnal variation for deficit patients. The french version of SDS was validated by Kirkpatrick after english back translation. We present here our psychometric data regarding reliability (assessed by weighted and unweighted kappa coefficients) and cohesiveness of the construct (assessed by rank-order correlations of each negative symptoms with the other five, using Spearman's rho). These data are quite significant and in agreement with the SDS authors.