A pilot neuropsychological study of Kraepelinian and non-Kraepelinian schizophrenia

Objective: This is the first study to report a direct comparison of neuropsychological performance in Kraepelinian vs. non-Kraepelinian schizophrenia (SZ). Methods: 17 Kraepelinian and 19 non-Kraepelinian subjects were assessed on a neuropsychological battery including the Purdue Pegboard, Schwartz' Reaction Time task, the Modified Card Sorting Test, the Wechsler's Associate Learning Test and the Digit Span. Results: Kraepelinian schizophrenia was characterized by more impaired performance on the Purdue Pegboard and the Card Sorting test. These differences remained significant when introducing, as covariates, the type of neuroleptic used, the use of anticholinergic medication, age and gender. Differences on the Reaction Time, the Associate Learning and the Digit Span tasks did not reach statistical significance. Conclusions: These results suggest that Kraepelinian schizophrenia is characterized by impaired performance on fine motor dexterity and executive functioning. These results further add to the evidence for the validity of the distinction between Kraepelinian and non-Kraepelinian schizophrenia as a strategy to better understand the factors influencing severity and/or outcome in schizophrenia.