Neuropsychological impairments in people with schizophrenia or bipolar disorder and their unaffected relatives

Abstract

This study finds evidence that intellectual abnormalities are related to a genetic liability to schizophrenia. Abnormalities of memory appear to be related to an increased liability to psychosis in general. No impairment was specific to bipolar disorder.

IQ tests as aids to diagnosis and management in early schizophrenia

“…The marked discrepancy between current verbal and performance IQ was also striking and is commonly found in established schizophrenia. However, lower IQ scores on performance tests relative to verbal tests are also found in people with severe psychiatric conditions other than schizophrenia (Heinrichs & Zakzanis, 1998;McIntosh et al, 2005), so this finding is not likely to be helpful diagnostically in this case. Notwithstanding the continuing diagnostic uncertainty, the patient was advised to take an atypical antipsychotic drug (risperidone) along with an antiobsessional drug (fluoxetine).…”

“…It is now well established that people with schizophrenia have on average a lower IQ than mentally healthy people or people with other forms of functional mental illness such as bipolar disorder (Heinrichs & Zakzanis, 1998;McIntosh et al, 2005). However, taken in isolation, this fact has little or no value for diagnosing schizophrenia in individual cases because low IQ may be an incidental finding unrelated to mental illness, and there is marked overlap of IQ scores of people with schizophrenia with those of healthy people.…”

“…An average reduction of 10 or more IQ points between estimated premorbid and current IQ is usually found in samples with long-standing established diagnoses of schizophrenia (e.g. Frith et al, 1991;McIntosh et al, 2005). Weickert et al (2000) reported reduced IQ in about 50% of such individuals.…”

Decreased cerebrospinal fluid secretogranin II concentrations in severe forms of bipolar disorder

“…[43][44][45] The diseases also share deficits in cognitive functions, 46,47 alterations in brain morphology 48,49 and response to antipsychotic medications, 50 suggesting that these disorders share many pathophysiological aspects. The diagnosis of bipolar disorder is mainly based on clinical assessments, and there is a lack of biological markers that, in addition to supplementing the diagnostic assessment, also could predict treatment response, side effects and/or disease progression.…”

The effects of HIV on P300 are moderated by familial risk for substance dependence: Implications for a theory of brain reserve

“…In addition, IQ and educational level overlap with other, more distal factors with greater relevance to genetic endowment. In recognition of these limitations, BR was defined in this study by one of the traditional metrics-verbal IQ--in the first set of analyses and by a metric--the presence/ absence of paternal alcohol or drug dependence--more relevant to genetic risk for diminished cognitive function, but not independent of the traditional metrics (Finn and Hall, 2004;McIntosh et al, 2005), in the second analysis set.…”