The Factorial Structure of the Schedule for the Deficit Syndrome in Schizophrenia

Abstract

Deficit schizophrenia (DS) is considered a distinct subtype within the diagnosis of schizophrenia. While the common assumption is that DS represents a single, cohesive domain of psychopathology, the factorial structure of DS has not been investigated. We assessed 52 individuals with DSM-IV diagnoses of schizophrenia with DS. A principal component analysis (PCA) was conducted on the symptoms of the Schedule for the Deficit Syndrome. The PCA resulted in 2 distinct factors explaining 73.8% of the variance. Factor 1 (avolition) is made up of symptoms of curbing of interests, diminished sense of purpose, and diminished social drive. Factor 2 (emotional expression) is made up of symptoms of restricted affect, diminished emotional range, and poverty of speech. The results indicate that DS is best characterized by these 2 factors. The great majority of participants (86%) displayed DS symptoms from both factors. On average, participants had 4.19 (S.D. = 1.39) symptoms that were primary, enduring, and at least moderate in severity. The mean severity of symptoms was 2.25 (S.D. = 1.06). We discuss possible links between the obtained factors and putative neurobiological mechanisms, as well as directions for future research.

Characterization of the Deficit Syndrome in Drug-Naive Schizophrenia Patients: The Role of Spontaneous Movement Disorders and Neurological Soft Signs

“…2,3,5 Furthermore, our study replicates the high temporal stability of the deficit syndrome, 41 such as the 2-factor structure of deficit features comprising volitional and emotional expressivity dimensions. 42,43 These findings confirm that the deficit/nondeficit categorization is replicable and reliable in first-admission, drug-naive patients and allows the identification of patients with consistent clinical characteristics across independent studies and differing samples. Moreover, the unique characteristics of our study sample-drugnaive patients-and design-two assessment points over 1-year follow-up-allowed us to eliminate the confounding factors of medication on the assessment of deficit and neurological symptoms, and the retrospective assessment bias of deficit symptoms.…”

Goal Representations and Motivational Drive in Schizophrenia: The Role of Prefrontal-Striatal Interactions

“…This distinction is supported by a range of exploratory and confirmatory analyses of symptom assessment scales that have consistently provided evidence for separate negative symptom factors for flat affect and anhedonia/avolition. As nicely articulated by Malaspina and colleagues, 4 separable factors for flat affect and anhedonia/ avolition have been identified in: (1) mixed groups of patients with a range of psychotic disorders [5][6][7] , (2) schizophrenia spectrum patients [8][9][10][11][12] , (3) deficit syndrome patients 4,13 , (4) patients on medications 4,9 , (5) patients off medications 12 , (6) first-episode patients 8 , (7) chronic patients 11 , and (8) patients across many different cultures. 5,6,8,10,13 The constructs of anhedonia/avolition play a major role in many theories of schizophrenia, including those that focus on liability to the disorder.…”

Social Anhedonia and Schizotypy in a Community Sample: The Maryland Longitudinal Study of Schizotypy

“…82 Given our use of this measure in a nonclinical sample of young adults, we utilized ratings to obtain a dimensional index of negative symptom characteristics (rather than a dichotomized ratings of presence vs absence of the deficit syndrome) based on the sum of the 6 SDS items. Dimensional ratings of SDS symptom severity have been employed in prior studies, 83 and dimensional ratings from the SDS have been shown to have high correlations with dimensional ratings obtained with other negative symptom instruments. 84 Internal consistency of this scale within the full sample was adequate (a = .70).…”