Stability of the Diagnosis of Deficit Syndrome in Schizophrenia: A 5-year Follow-up Study

Park, Dong Yeon; Choi, Kyeong Sook; Lee, Dongsoo; Hong, Kyung Sue

Abstract

OBJECTIVES
Primary, enduring negative symptoms have been used to define the deficit syndrome of schizophrenia, and the diagnostic validity of the deficit syndrome has been demonstrated by clinical, biological and neuropsychological studies. This study aims at evaluating the long-term stability of the diagnostic category of deficit syndrome using direct patient assessments.
METHODS
The subjects were thirty-two patients with schizophrenia who were categorized into deficit or non-deficit subgroup using the Schedule for the Deficit Syndrome (SDS) in their remission or partial remission state maintained by long-term treatments with antipsychotics (mostly atypical drugs). These patients were re-assessed based on the same deficit syndrome criteria an average of 5.6 years after having been initially categorized. Lifetime presence of clinical symptoms were evaluated using the Krawiecka Scale.
RESULTS
The majority (87.5%) of the patients who were classified as non-deficit at the initial assessment continued to remain non-deficit during the follow-through period. However, only 37.5% of the patients classified as deficit at the initial assessment remain classified as showing deficit syndrome. Compared to the non-deficit group, patients of the deficit group at the final assessment showed significantly higher scores of positive symptoms at their previous psychotic states. Among the individual items of SDS, 'poverty of speech' was the most predictable of the long-lasting deficit syndrome.
CONCLUSION
This study showed insufficient long-term stability of the deficit syndrome categorized by SDS criteria. This could be explained by low validity of SDS criteria for the identification of the trait-dependent deficit syndrome. It might also suggest that deficit symptoms could be improved by optimal long-term treatment with atypical antipsychotics.