What Do We Know About Neuropsychological Aspects Of Schizophrenia?

Abstract

Application of a neuropsychological perspective to the study of schizophrenia has established a number of important facts about this disorder. Some of the key findings from the existing literature are that, while neurocognitive impairment is present in most, if not all, persons with schizophrenia, there is both substantial interpatient heterogeneity and remarkable within-patient stability of cognitive function over the long-term course of the illness. Such findings have contributed to the firm establishment of neurobiologic models of schizophrenia, and thereby help to reduce the social stigma that was sometimes associated with purely psychogenic models popular during parts of the 20th century. Neuropsychological studies in recent decades have established the primacy of cognitive functions over psychopathologic symptoms as determinants of functional capacity and independence in everyday functioning. Although the cognitive benefits of both conventional and even second generation antipsychotic medications appear marginal at best, recognition of the primacy of cognitive deficits as determinants of functional disability in schizophrenia has catalyzed recent efforts to develop targeted treatments for the cognitive deficits of this disorder. Despite these accomplishments, however, some issues remain to be resolved. Efforts to firmly establish the specific neurocognitive/neuropathologic systems responsible for schizophrenia remain elusive, as do efforts to definitively demonstrate the specific cognitive deficits underlying specific forms of functional impairment. Further progress may be fostered by recent initiatives to integrate neuropsychological studies with experimental neuroscience, perhaps leading to measures of deficits in cognitive processes more clearly associated with specific, identifiable brain systems.

From “What” to “How”: The Effort to Fill the Gaps in Understanding Cognitive Processes Underpinning Remission in Schizophrenia

“…These results are consistent with those of previous literature that have noted decline of cognitive functions at the time of onset of clinical symptoms with partial recovery of cognitive functions during the stabilization phase after first onset [23].…”

“…Cognitive functioning has been found to be improved in recovery [21], and a better cognitive performance was associated with the adequate social/vocational functioning and symptom remission components of recovery [12], strengthening the considerable amount of the evidences that supports the substantial influence of cognition on functional capacity yielding autonomous everyday functioning in schizophrenia patients [22,23].…”

Preserved, deteriorated, and premorbidly impaired patterns of intellectual ability in schizophrenia.

“…Hence, a substantial minority, 20-25%, must overlap with healthy people on many standard cognitive tasks. Indeed, a number of studies have corroborated the implications of meta-analytic findings and identified groups of patients with schizophrenia displaying statistically average levels of neuropsychological functioning (Ammari, Heinrichs, & Miles, 2010;Heinrichs et al, 2008;Kremen et al, 2000;Palmer, Dawes, & Heaton, 2009;Palmer et al, 1997;Rund et al, 2006;Weickert et al, 2000;Wexler et al, 2009). In a seminal study, using a combination of expert ratings and normative criteria, Palmer and colleagues (1997) identified 27.5% of their sample of schizophrenia patients as neuropsychologically normal on a variety of cognitive measures, including general intellectual ability or IQ.…”

Cannabis and cognitive performance in psychosis: a cross-sectional study in patients with non-affective psychotic illness and their unaffected siblings

“…Cognitive impairment is recognized as a core feature of schizophrenia (Green, 1996 ;Palmer et al 2009). Mild cognitive alterations are also observed in unaffected relatives of patients who are at increased risk to develop a psychotic disorder (Snitz et al 2006).…”