Divided Attention in Schizophrenia: A Dual Task Paradigm

Abstract

Schizophrenia is known to be associated with attentional deficits. Few studies have examined whether the disorder is also associated with a deficit in the ability to divide attention, and they have given contradictory results. Some have reported that patients show greater loss of performance than healthy controls when moving from single tasks to dual tasks, and others have reported that performance loss is similar in both groups or even that patients perform the dual task better than either task on its own. To help resolve this controversy, we performed a first study in which we designed a dual task paradigm with a group of 36 healthy participants. This dual task involves 2 tasks of equivalent difficulty that make use of different sensory modalities. In the second study, we gave this dual task to 23 patients with schizophrenia and 25 healthy participants. Both groups decreased similarly their performance in dual tasks, but the patients showed lower baseline performance in the single task. Our findings suggest that patients with schizophrenia and healthy participants use similar strategies to divide their attention, but in a high-degrading stimuli condition patients perform below the controls in a single task.