The presence of neurocognitive deficits in the affective and psychotic psychiatric disorders (i.e., bipolar disorder with psychotic features, bipolar disorder without psychotic features, and schizophrenia) has been well documented, with such these deficits having been found to overlap across these diagnostic categories to a degree. Along with other types of evidence reported, these findings suggest that bipolar disorder and schizophrenia may not be isolated disorders as suggested by the current diagnostic criteria outlined in the DSM-IV (APA, 1994), but rather may be related disorders on a spectrum marked by bipolar disorder without psychosis on one end and by schizophrenia on the other end, with bipolar disorder with psychosis and schizoaffective disorder occupying the middle of the spectrum, an idea known as the spectrum hypothesis.The purpose of this study was primarily to examine the presence of and, if relevant, severity of verbal and visual learning and memory impairments in individuals with bipolar disorder with and without psychotic features. A secondary purpose of this study was to examine, if present, the severity of these same neurocognitive impairments in individuals with schizophrenia, who were included as a validity check for the expected spectrum of performance across the groups. It was anticipated that impairments would be identified that would not only provide support for the spectrum hypothesis, but would also differentiate between psychiatric disorders with and without psychotic features.
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