CLINICAL HANDBOOK OF SCHIZOPHRENIA

250 IV. PSYCHOSOCIAL TREATMENTThe detailed investigation of cognitive difficulties in the past decade has concludedthat there are general deficits in multiple functions of attention, learning, and memory. Inparticular, executive functions, which include planning and strategy use, have beenshown to be deficient. Although measuring differences between cognitive functions dependson the sensitivity of the tests, the general consensus is that memory difficulties arepervasive and specific. In other words, they are present even when there are no obviousabnormalities in overall cognitive function.Severe cognitive impairments are not only important to service users but also havebeen shown to have a crucial association with functional outcomes, such as getting orkeeping a job. They are also linked to the cost of mental health care. This relationship isoften stronger than that with positive symptoms. But perhaps the clincher in the need tofocus rehabilitation efforts on cognition is that there is now clear evidence that cognitivedifficulties interfere with rehabilitation efforts in multiple domains of functioning. Cognitionnot only interferes with everyday life but it also limits functional outcomes over longperiods of time and hinders the rehabilitation of specific functioning (Green, Kern, Braff,& Mintz, 2000; McGurk & Mueser, 2004; Wexler & Bell, 2005).DEVELOPING THERAPIES FOR COGNITIVE DIFFICULTIESThis slowness of therapy development was due largely to the assumption that cognitiveimpairments were immutable, based on observations of largely unvarying cognitive difficultiesover the course of the disorder. It was also proposed that these difficulties wereneurological problems similar to frontal lobe lesions. Because there was little positive evidencefor the effects of therapy on cognition in patients with frontal lobe lesions, this pessimismwas transferred to schizophrenia and, when care moved from institutions to thecommunity, had the effect of concentrating rehabilitation efforts on teaching specific lifeskills.The initial boost to the development of therapy for cognitive problems came from anunexpected source: research on the immutability of cognitive difficulties (Goldberg,Weinberger, Berman, Pliskin, & Podd, 1987). One major U.S. study purported to showthat it was impossible to teach inpatients with chronic schizophrenia how to carry out aparticular neuropsychological test, the Wisconsin Card Sorting Test (WCST), which measuresflexibility of thought. In the results of this study, shown in Figure 25.1, it is clearthat training was not successful in improving performance until the participants wereprovided with specific, card-by-card instructions. However, as soon as this learning supportwas removed, performance returned to baseline and was no different in the groupthat had just repeated the test five times. This study produced a boost in research, leadingto a line of inquiry that attempted to find out whether any type of instruction would havelonger lasting effects; in other words, the experiments were designed to test the null hypothesisthat cognition was immutable. Although many studies supported immutability, afew showed that it was possible under some conditions not only to improve performancebut also to produce durable improvements. These results produced the vital bit of therapeuticoptimism, and a new psychosocial rehabilitation technology was born.WHAT SHOULD BE A TARGET FOR COGNITIVE REHABILITATION?Cognitive difficulties cover a broad range and show interindividual variation. Clearly, anintervention designed to have the most impact on a person’s life needs to be targeted, but