Planning impairment in schizophrenia: The possible role of abstract thinking and short-term memory

Abstract

Introduction

The planning impairment is one of the basic aspect of cognitive dysfunction, but its mechanisms in schizophrenia remain unclear.

Objectives

To assess the links between planning and cognitive functioning in schizophrenic patients and in norm.

Methods

50 patients with schizophrenia (age 34.92±8.54; illness duration 8.34±5.87) and 50 healthy volunteers (age 32.42±7.26) were examined. Brief Assessment of Cognition in Schizophrenia, Benton’s test for short-term memory assessment; sub-test Similarity (from WAIS) to assess abstract thinking were used.

Results

Patients showed significantly worse results in all parameters (Tab.1). Table 1: Differences of planning between groups.

	Schizophrenia	Norm	p-level
TOL-DX	92,64±14,48	102,52±11,97	0,00033
Similarity	16,92±3,97	19,76±2,85	0,00009
BVTR Score	6,73±1,78	7,60±1,32	0,00709

In healthy subjects, significant relationship was found between planning and abstract thinking, and there was no relationship between planning and short-term memory (Tab.2). Table 2: Correlations in the Norm group

	Spearman R	p-level
TOL-DX & Similarity	0,392530	0,004809
TOL-DX & BVTR	0,186494	0,194710

In patients with schizophrenia, the opposite picture was observed (Tab.3). Table 3: Correlations in the Schizophrenia group.

	Spearman R	p-level
TOL-DX & Similarity	0,262389	0,071596
TOL-DX & BVTR	0,344566	0,015331

The effectiveness of planning in patients was significantly associated with short-term memory, but not with abstract thinking.

Conclusions

Study results indicate a possible role of basic aspects of mental activity such as short-term memory in planning impairment in patients with schizophrenia. Problem solving and reasoning disorders represent two relatively independent forms of thought disorders in schizophrenia.