Objective: Primary, enduring negative symptoms have been distinguished from
negative symptoms more generally and are used to define the deficit syndro
me of schizophrenia. Although the validity of the deficit syndrome has been
demonstrated by using brain imaging, neuropsychological, illness outcome,
and developmental history data, the stability of this diagnostic category h
as not been tested prospectively by using direct patient assessments. Metho
d: Forty-three outpatients with schizophrenia and schizoaffective disorder
were categorized into deficit and nondeficit groups an average of 3.8 years
after having been previously categorized. Results: There was 83% agreement
between initial and blind follow-up designations of deficit status and 88%
agreement on the nondeficit categorization. Conclusions: These results pro
vide evidence for the long-term stability of the deficit syndrome in patien
ts with schizophrenia and the reliability of the deficit/nondeficit categor
ization when diagnosed by those with appropriate training. Furthermore, the
y validate the method of categorizing deficit patients by using cross-secti
onal and retrospective data.