59 Epidemiological studies of premorbid cognitive functioning (eg, in childhood or adolescence) may point to a possible qualitative difference between different psychotic disorders. There is a well documented premorbid cognitive deficit in schizophrenia. A recent meta-analysis estimated that, on average,

future schizophrenia Inhibitors,research,lifescience,medical cases exhibit an 8-point deficit (.5 standard deviations) in their childhood IQ. 65 Recent studies suggest that abnormal premorbid IQ is also a characteristic of depression.66,67 In contrast, epidemiological research suggests that future bipolar disorder patients may have superior intellectual ability. This has been reported in some,66,68,69 although not all studies,70,71 and requires further investigation. If supported, the differences in premorbid functioning may point to potential Inhibitors,research,lifescience,medical developmental discrimination between schizophrenia, depression, and bipolar disorder. “Cognitive impairment” in schizophrenia: who is impaired and who is not? From the previous sections it is well accepted that schizophrenia patients, as a group, have cognitive deficits. Several previous studies, however, demonstrate that in some persons with schizophrenia,

cognitive abilities are unimpaired or normal.3,72,74 The central issue Inhibitors,research,lifescience,medical is which patients can be identified as having a cognitive deficit.75 Some conceptualizations Inhibitors,research,lifescience,medical of this issue have relied on approaches from clinical neuropsychology to define cognitive impairment. These definitions are based on a performance deficit selleck chem compared with a healthy

control population (or normative data), such as one standard deviation below the mean on one or more areas of cognitive function. Using such definitions the estimated percentage of schizophrenia patients who have a cognitive small molecule impairment has varied from between 70% to 80%54,73 to no more than 55 %.74 A recent study54 compared various classification methods of cognitive impairment using neuropsychological Inhibitors,research,lifescience,medical Drug_discovery assessment data from the Suffolk County Mental Health Project cohort.76,77 Of the 94 persons with schizophrenia in the study, 82% to 84% were classified as neuropsychologically impaired (Figure 3) . The rate of impairment was lower for other psychotic disorders.54 Figure 3. Rates and severity of cognitive impairment in schizophrenia patients. Data came from the Suffolk County Mental Health Project cohort54,76,77 (N=94 cases). Definition of impairment Mild: Performance between 1 and 2 standard deviations below norms on at … Schizophrenia-specific and abbreviated neuropsychological assessment batteries Traditionally, many of the neuropsychological assessment batteries used are long and complex and may require several hours to administer.