Ivan J. Torres

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OBJECTIVE Although cognitive deficits are prominent in symptomatic patients with bipolar disorder, the extent and pattern of cognitive impairment in euthymic patients remain uncertain. METHOD Neuropsychological studies comparing euthymic bipolar patients and healthy controls were evaluated. Across studies, effect sizes reflecting patient-control(More)
Functional neuroimaging studies in schizophrenia have demonstrated abnormal activation of dorsolateral prefrontal cortex (DLPFC) during working memory (WM) performance. However, findings of increased and decreased activity have been reported. The authors used meta-analysis to investigate whether diverging results arise as a function of differential WM task(More)
Polydipsic hyponatremic schizophrenic patients (PHS) exhibit enhanced plasma arginine vasopressin (pAVP) and hypothalamic pituitary adrenal (HPA) axis responses to stress that appear attributable to anterior hippocampal dysfunction. Neuroanatomic and electrophysiologic studies indicate oxytocin activity in PHS patients should also be affected. Furthermore,(More)
OBJECTIVE Neuroimaging studies have provided robust evidence that schizophrenia is associated with structural brain abnormalities. However, the underlying pathophysiology of these changes is still unknown. By evaluating brain morphology early in the course of illness, confounding effects of treatment and duration of illness are minimized. The goal of this(More)
We examined the pattern of neuroanatomic abnormalities in adults with Down's syndrome (DS) and the cognitive correlates of these abnormalities. Specifically, we compared this pattern with what would be predicted by the hypotheses attributing DS pathology to either premature aging or Alzheimer's disease. We measured a number of brain regions on MRIs of 25(More)
OBJECTIVES Although cognitive impairment is recognized as an important clinical feature of bipolar disorder, there is no standard cognitive battery that has been developed for use in bipolar disorder research. The aims of this paper were to identify the cognitive measures from the literature that show the greatest magnitude of impairment in bipolar(More)
BACKGROUND Although cognitive deficits in bipolar disorder have been associated with diminished functional outcome, this relationship has been studied primarily through cross-sectional designs, and has not been studied in patients early in the course of illness. The purpose of this study was to evaluate the impact of cognitive functioning on longitudinal(More)
Brain mechanisms involved in the maintenance of attention to auditory and visual stimuli at different spatial locations were assessed using positron emission tomography with [15O]water to measure regional cerebral blood flow (rCBF) changes in 13 normal volunteers. Simultaneous auditory [dichotically presented consonant-vowel-consonants (CVCs)] and visual(More)
OBJECTIVE Although cognitive impairment is an important clinical feature of bipolar disorder, it is unknown whether deficits are present at illness onset. The purpose of this study was to determine whether neuropsychological impairments are present in clinically stable patients with bipolar disorder shortly after resolution of their first manic episode. (More)
Patients with schizophrenia and water imbalance may represent a subset of patients with distinct pathophysiological abnormalities and susceptibility to cognitive impairment. Specifically, patients with polydipsia and hyponatremia have been shown to have smaller anterior hippocampal volumes, which are also associated with various impairments in(More)