Our work has focused on characterizing various facets of cognitive failure in schizophrenia. We have attempted in particular: 1. To examine executive functions. Studies have included the development of an auditory sort task that is analogous to the Wisconsin Card Sorting Test and the development of novel delayed response-delayed attenuation type task. Both tests have been designed to be used as cognitive activators during SPECT and PET studies. 2. To examine memory functions. Studies have included examination of procedural vs. declarative distinctions, the utility of Brown Peterson/release from proactive interference paradigms, list learning, implicit vs. explicit learning, and effortful vs. automatic processing. 3. To examine specificity. We are assessing cognitive functions in twins discordant for affective disorder, twins discordant for schizophrenia, temporal lobe epilepsy (at Walter Reed), and traumatic brain injury (at NRH). 4. To examine the relation of cognition to psychopathology. Chapman Scales of anhedonia, perceptual aberration, and magical ideation offer the possibility of ascertaining meaningful relations between brain abnormalities and psychological abnormalities. 5. To examine cognitive enhancing strategies. We have examined the effects of amphetamine on frontal tasks and are beginning a trial of the nootropic piracetam. Studies on anticholinergic effects on memory are also underway. 6. To examine the relation between basal ganglia function, cognitive impairment, and psychopathology. We are intensively assessing MZ twins with Tourettes syndrome on neuropsychology, psychopathology, and MRI.
